a balanced equation is not necessary to perform calculations involving δhrxn

Answers

Answer 1

A balanced equation is a crucial component in calculating the enthalpy change of a reaction (δhrxn). This is because the enthalpy change is a function of the stoichiometry of the reaction, and the balanced equation provides the necessary coefficients to determine the relative amounts of reactants and products that are involved. In other words, the coefficients in the balanced equation represent the number of moles of each substance that are involved in the reaction.

It is not possible to perform accurate calculations involving δhrxn without a balanced equation. Without a balanced equation, it is impossible to determine the exact number of moles of each reactant and product involved in the reaction, which would lead to incorrect calculations of the enthalpy change. In addition, a balanced equation ensures that the law of conservation of mass is satisfied, which is essential in any chemical reaction. A balanced equation is necessary to perform accurate calculations involving δhrxn. It provides the necessary information regarding the stoichiometry of the reaction, allowing for the accurate determination of the enthalpy change. Without a balanced equation, the calculations would be inaccurate and unreliable.

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Related Questions

How much CaCl2 will be produced if you start with 140.0g of Ca(OH)2 and 115.6g of HCI?
Ca(OH)2 + 2HCI ---> CaCl2 + 2H2O


please help

Answers

209.8 g CaCl₂ will be produced if you start with 140.0g of Ca(OH)₂ and 115.6g of HCI.

Calculate the moles of each reactant using their respective molar masses:

Moles of Ca(OH)₂ = 140.0 g / 74.09 g/mol

= 1.891 mol

Moles of HCl = 115.6 g / 36.46 g/mol

= 3.172 mol

According to the balanced chemical equation, the stoichiometric ratio between Ca(OH)₂ and HCl is 1:2. This means that for every 1 mole of Ca(OH)₂, 2 moles of HCl react completely.

Moles of HCl (3.172 mol) than required to react with all the Ca(OH)₂ (1.891 mol). This means that HCl is in excess and Ca(OH)₂ is limiting the reaction.

Using the stoichiometric ratio, calculate the theoretical yield of CaCl₂:

Moles of CaCl₂ = 1.891 mol Ca(OH)₂ x (1 mol CaCl₂ / 1 mol Ca(OH)₂)

= 1.891 mol CaCl₂

To convert moles to grams, use the molar mass of CaCl₂:

Mass of CaCl₂ = 1.891 mol x 110.98 g/mol

= 209.8 g

Therefore, the theoretical yield of CaCl₂ is 209.8 g.

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it takes 48.0 j to raise the temperature of an 11.9 g piece of unknown metal from 13.0 ∘c to 24.9 ∘c . what is the specific heat for the metal? express your answer with the appropriate units.

Answers

The specific heat of the unknown metal is approximately 0.338 J/(g·°C).The specific heat (c) of a substance is defined as the amount of heat required to raise the temperature of 1 gram of the substance by 1 degree Celsius.

To find the specific heat of the unknown metal, we can use the formula:

q = mcΔT

where q is the amount of heat transferred, m is the mass of the metal, c is the specific heat of the metal, and ΔT is the change in temperature.

In this problem, we are given the following information:

q = 48.0 J

m = 11.9 g

ΔT = 24.9 °C - 13.0 °C = 11.9 °C

Substituting these values into the formula, we get:

48.0 J = (11.9 g) c (11.9 °C)

Solving for c, we get:

c = 48.0 J / (11.9 g × 11.9 °C) ≈ 0.338 J/(g·°C)

Therefore, the specific heat of the unknown metal is approximately 0.338 J/(g·°C).

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at 3278c, the equilibrium concentrations are [ch3oh] 5 0.15 m, [co] 5 0.24 m, and [h2] 5 1.1 m for the reaction ch3oh1 g2mco1 g2 1 2h2 1 g2 calculate kp at this temperature.

Answers

At chemical equilibrium, the equilibrium constant of a chemical reaction is the value of its reaction quotient, a state proceeds by a dynamic chemical system after enough time has passed at which its composition has no quantifiable tendency towards further change.

To calculate the equilibrium constant (Kp) at [tex]3278^{0} C[/tex], we can use the following equation:

[tex]Kp=(Pco)^{2} * PH^{2} /Pch^{2}oh[/tex]


where P represents the partial pressure of each gas in the reaction. We can convert the concentrations given in the problem to partial pressures using the ideal gas law:

[tex]P = nRT/V[/tex]

where n is the number of moles of gas, R is the gas constant, T is the temperature in Kelvin, and V is the volume. At equilibrium, the number of moles of each gas will be constant, so we can use the given concentrations to calculate the number of moles and then use the ideal gas law to find the partial pressures.
[tex][ch_{3} oh]=0.15M[/tex][tex]
[tex][co]=0.24M[/tex]

[tex][h_{2} ]=1.1M[/tex]

The molar mass of each gas is:

[tex]Mch_{3} oh=32.04g/mol[/tex]
[tex]Mco=28.01g/mol[/tex]
[tex]Mh_{2} =2.02g/mol[/tex]

We can calculate the number of moles of each gas using the given concentrations and the volume of the system:

[tex]nch_{3} oh=0.15mol/L*1L=0.15mol[/tex]

[tex]nco=0.24mol/L*1L=0.24mol[/tex]
[tex]nh_{2} =1.1mol/L*1L=1.1mol[/tex]

Using the ideal gas law, we can convert the number of moles to partial pressures:

[tex]Pch_{3} oh=nch_{3} oh*R*T/V=0.15mol*0.08206L atm/mol K*3551K/1L=4.73atm[/tex]

[tex]Pco=nco*R*T/V=0.24mol*0.08206L atm/mol K*3551K/1L=7057atm[/tex]
[tex]PH_{2} =nh_{2} *R*T/V=1.1 mol*0.08206Latm/molK*3551K/1L=34.98atm[/tex]

Now we can plug these values into the equation for Kp:
[tex]kp=(Pco)^{2} *PH_{2} /Pch_{3} oh[/tex]
[tex]p=(7.57atm)^{2} *2*34.98atm/4.73atm[/tex]
kp=4.95*[tex]10^{4}[/tex]

Therefore, the equilibrium constant (Kp) at [tex]3278^{0} C[/tex] for the reaction [tex]ch_{3} oh_{1}  g_{2} mco_{1} g_{21} 2h_{2} 1g_{2}[/tex] is [tex]4.95*10^{4}[/tex].

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What is the pH of a 0.24 mg/ml solution of CsOH

Answers

To find the pH of a solution of CsOH, we need to first determine the concentration of hydroxide ions (OH-) in the solution.

CsOH is a strong base that completely dissociates in water to produce Cs+ ions and OH- ions. Since the given concentration is in milligrams per milliliter (mg/ml), we need to convert it to molarity (mol/L) first. The molar mass of CsOH is 168.92 g/mol, so:

0.24 mg/ml = 0.24 g/L = 0.24/168.92 mol/L = 0.00142 M

Therefore, the concentration of OH- ions is also 0.00142 M, and the pOH can be calculated as:

pOH = -log[OH-] = -log(0.00142) = 2.847

Finally, we can use the relationship between pH and pOH:

pH + pOH = 14

To solve for pH:

pH = 14 - pOH = 14 - 2.847 = 11.153

Therefore, the pH of a 0.24 mg/ml solution of CsOH is 11.153.

Final answer:

To find the pH, we first need to convert the concentration of CsOH to molarity. Since CsOH is a strong base, we compute the pOH first, and then find the pH using the relationship pH + pOH = 14.

Explanation:

To solve this problem, we first need to find the concentration of the CsOH solution in molarity (M). Given that CsOH has a molar mass of approximately 197.02 g/mol, the molarity can be found by converting milligrams to grams and milliliters to liters, and then using the formula M = n/V. The formula gives us the concentration in moles per liter.

Since pH measures the acidity or basicity of a solution, and CsOH is a strong base that fully dissociates in water, we note that in this case, it would be more appropriate to find the pOH (the measure of hydroxide ion concentration) first. This is done with the formula pOH = -log[OH-].

Finally, we can find the pH using the relation pH + pOH = 14 at 25°C (a typical standard temperature).

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when a substance is in its elemental form (existing alone without bonds to other elements), the oxidation number is .

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The oxidation number of an element in its elemental form (existing alone without bonds to other elements) is zero.


Oxidation number is the charge an atom would have if the compound was composed of ions. When an element exists alone without any bonds to other elements, it is in its elemental form. In this state, the oxidation number of the element is zero since there are no other atoms to share or take electrons from it.

For example, the oxidation number of oxygen in O₂ is zero because each oxygen atom shares electrons equally with the other oxygen atom. Similarly, the oxidation number of hydrogen in H₂ is zero because each hydrogen atom shares electrons equally with the other hydrogen atom. It is important to note that the oxidation number can change when an element forms a compound with other elements.

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What is the percentage of SiO2 in a sample weighing 7.69 g if 3.27 g of SiO2 have been recovered?A)42.5 %B)52.0%C)60 %D)67%

Answers

The percentage of [tex]SiO_{2}[/tex] in a sample weighing 7.69 g if 3.27 g of [tex]SiO_{2}[/tex] have been recovered is option D) 67%.

To arrive at this answer, we can use the formula:
Percentage of [tex]SiO_{2}[/tex] = (Mass of recovered [tex]SiO_{2}[/tex] ÷ Mass of sample) x 100
Plugging in the values given in the question, we get:
Percentage of [tex]SiO_{2}[/tex] = (3.27 g ÷ 7.69 g) x 100 = 42.5%
However, this is the percentage of [tex]SiO_{2}[/tex] recovered, not the percentage of [tex]SiO_{2}[/tex] in the original sample. To find the latter, we can use the fact that the mass of [tex]SiO_{2}[/tex] in the original sample must be equal to the mass of [tex]SiO_{2}[/tex] recovered:
Mass of [tex]SiO_{2}[/tex] in original sample = Mass of [tex]SiO_{2}[/tex] recovered
Let x be the percentage of [tex]SiO_{2}[/tex] in the original sample. Then we can set up the equation:
x% of 7.69 g = 3.27 g
Solving for x, we get:
x = (3.27 g ÷ 7.69 g) x 100 = 42.5%
So the percentage of [tex]SiO_{2}[/tex] in the original sample is 42.5%, which means that option A is incorrect.
To get the main answer, we need to calculate the percentage of the sample that is not [tex]SiO_{2}[/tex]:
Percentage of other substances = 100% - Percentage of [tex]SiO_{2}[/tex]
Percentage of other substances = 100% - 42.5% = 57.5%
This means that the original sample was 57.5% other substances and 42.5% [tex]SiO_{2}[/tex].
Now we can use this information to find the percentage of [tex]SiO_{2}[/tex] in a sample weighing 7.69 g if 3.27 g of SiO2 have been recovered:
Percentage of [tex]SiO_{2}[/tex] = (Mass of [tex]SiO_{2}[/tex] in sample ÷ Sample mass) x 100
Let y be the mass of the sample that is not [tex]SiO_{2}[/tex]. Then we can set up the equation:
3.27 g = 0.425(7.69 g) + y
Solving for y, we get:
y = 7.69 g - 3.27 g/0.425 = 12.56 g
So the mass of the sample that is not [tex]SiO_{2}[/tex] is 12.56 g.
Now we can calculate the mass of [tex]SiO_{2}[/tex] in the original sample:
Mass of SiO2 in sample = 0.425(7.69 g) = 3.27 g
Since 3.27 g of [tex]SiO_{2}[/tex] have been recovered, the mass of [tex]SiO_{2}[/tex] in the remaining sample is:
3.27 g + 3.27 g = 6.54 g
Therefore, the percentage of [tex]SiO_{2}[/tex] in the remaining sample is:
Percentage of [tex]SiO_{2}[/tex] = (6.54 g ÷ 20.25 g) x 100 = 32.3%
This means that the sample weighing 7.69 g originally contained 42.5% [tex]SiO_{2}[/tex] and the remaining sample after 3.27 g of [tex]SiO_{2}[/tex] was recovered contains 32.3% [tex]SiO_{2}[/tex].

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At constant pressure, the following reaction 2NO2(g)------>N2O4(g) is exothermic. the reaction (as written) isa) always spontaneousb) spontaneous at low temperatures, but not high temperaturesc) spontaneous at high temperatures, but not low temperaturesd)never spontaneouse) cannot tell

Answers

The correct answer is (c) spontaneous at high temperatures, but not low temperatures.At constant pressure, the spontaneity of a reaction is determined by the change in Gibbs free energy (∆G).

If ∆G is negative, the reaction is spontaneous and if it is positive, the reaction is non-spontaneous.

In the given reaction, 2NO2(g) ------> N2O4(g), the reaction is exothermic, which means that it releases heat.

This indicates that the products have lower energy than the reactants. However, this alone does not determine the spontaneity of the reaction. The change in entropy (∆S) also plays a role in determining the spontaneity.
In this case, the reaction involves a decrease in the number of moles of gas (2 moles of NO2 gas to 1 mole of N2O4 gas), which leads to a decrease in entropy (∆S<0). Thus, the spontaneity of the reaction depends on the temperature. At low temperatures, the decrease in entropy dominates and makes the reaction non-spontaneous (∆G>0). At high temperatures, the decrease in Gibbs free energy (∆G<0) due to the exothermic nature of the reaction dominates, making the reaction spontaneous. Therefore, the correct answer is (c) spontaneous at high temperatures, but not low temperatures.

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Balance the following redox reaction if it occurs in acidic solution. What are the coefficients in front of Cd and Agt in the balanced reaction? Cd(s) + Ag+(aq) → Ag(s) + Cd2+(aq) Cd = 3, Ag+ = 3 Cd = 2, Ag = 4 Cd = 1, Ag = 2 Cd = 1, Ag* = 1 Cd = 2, Ag = 2

Answers

The coefficients in front of Cd and Ag in the balanced equation are 2 and 1, respectively. Therefore, the correct answer is (d) Cd = 1, Ag* = 1.

To balance the redox reaction, we can follow these steps:

Write the unbalanced half-reactions for the oxidation and reduction processes:

Oxidation: Cd(s) → Cd²⁺(aq) + 2e⁻

Reduction: Ag⁺(aq) + e⁻ → Ag(s)

Balance the number of atoms of each element in each half-reaction, excluding O and H:

Oxidation: Cd(s) → Cd²⁺(aq) + 2e⁻

Reduction: Ag⁺(aq) + e⁻ → Ag(s)

Balance the number of oxygen atoms by adding H₂O molecules to the half-reaction that needs them:

Oxidation: Cd(s) → Cd²⁺(aq) + 2e⁻

Reduction: Ag⁺(aq) + e⁻ + H₂O(l) → Ag(s) + 2OH⁻(aq)

Balance the number of hydrogen atoms by adding H⁺ ions to the half-reaction that needs them:

Oxidation: Cd(s) → Cd²⁺(aq) + 2e⁻

Reduction: Ag⁺(aq) + e⁻ + H₂O(l) → Ag(s) + 2OH⁻(aq) + H⁺(aq)

Multiply one or both half-reactions by an integer to make the number of electrons transferred equal in both half-reactions. In this case, the oxidation half-reaction needs to be multiplied by 2 to balance the electrons:

Oxidation: 2Cd(s) → 2Cd²⁺(aq) + 4e⁻

Reduction: Ag⁺(aq) + e⁻ + H₂O(l) → Ag(s) + 2OH⁻(aq) + H⁺(aq)

Add the half-reactions together and simplify by canceling out any species that appear on both sides of the equation:

2Cd(s) + Ag⁺(aq) + 2H₂O(l) → 2Cd²⁺(aq) + Ag(s) + 2OH⁻(aq) + H⁺(aq)

The coefficients in front of Cd and Ag in the balanced equation are 2 and 1, respectively. Therefore, the correct answer is (d) Cd = 1, Ag* = 1.

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--The complete question is, Balance the following redox reaction if it occurs in acidic solution. What are the coefficients in front of Cd and Agt in the balanced reaction? Cd(s) + Ag+(aq) → Ag(s) + Cd2+(aq)

a. Cd = 3, Ag+ = 3

b. Cd = 2, Ag = 4

c. Cd = 1, Ag = 2

d. Cd = 1, Ag* = 1

e. Cd = 2, Ag = 2--

which of the following choices is the best explanation for why it does not matter how much water you added when dissolving the acid or when carrying out the titration? the titration equivalence point occurs when the moles of acid present in the sample have been exactly neutralized by the moles of base added. additional water added to the reaction vessel has no effect on the moles of base added. water is neither a reactant nor a product of the neutralization reaction and therefore does not affect the measurement. the volume of the sample plus titrant is constant throughout the titration even if external water is added. none of the above.

Answers

The correct option is C, The best explanation for why it does not matter how much water you added when dissolving the acid or when carrying out the titration is: water is neither a reactant nor a product of the neutralization reaction and therefore does not affect the measurement.

Titration is a common laboratory technique used in chemistry to determine the concentration of an unknown solution by reacting it with a solution of known concentration. The process involves slowly adding the known solution, called the titrant, to the unknown solution, called the analyte, until the reaction is complete.

Titration is typically carried out using an indicator, which changes color when the reaction is complete, indicating the endpoint of the titration. The most commonly used indicators include phenolphthalein, bromothymol blue, and methyl orange. Titration is widely used in a variety of applications, including in the pharmaceutical industry to measure the potency of drugs, in environmental testing to measure the concentration of pollutants, and in food science to determine the acidity of foods and beverages.

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The picture below shows a closed system before and after undergoing a change.
System before change
System after change
What was changed in the system?

Answers

Answer:

Based on your description, it seems that the change in the system is that the water in the container was heated. This could have caused a change in temperature and possibly a change in the physical state of the water (from liquid to gas).

Explanation:

for the auto-ionization of water, δrh∘=5.58×104 j/mol. 2h2o(l)↽−−⇀h3o (aq) oh−(aq)kw=1.0×10−14 at 25∘c assuming that δrh∘ is constant over the temperature range 25–100°c, calculate kw at 52 ∘c.

Answers

The value of kw at 52°C is 8.3×10^-12.  The van't Hoff equation relates the change in equilibrium constant to the change in temperature.

ln(K2/K1) = -(ΔH°/R)[(1/T2) - (1/T1)]

where K1 and K2 are the equilibrium constants at temperatures T1 and T2, respectively, ΔH° is the standard enthalpy change, and R is the gas constant.

In this case, we want to find kw at 52°C, so we need to use the van't Hoff equation to calculate the equilibrium constant at 25°C and 52°C, and then use the equation kw = [H3O+][OH-] to find kw at 52°C.

First, let's calculate the equilibrium constant at 25°C (298 K) using the known value of kw:

kw = [H3O+][OH-] = 1.0×10^-14

[H3O+] = [OH-] = sqrt(kw) = 1.0×10^-7 M

The equilibrium constant expression for the auto-ionization of water is:

K = [H3O+][OH-]/[H2O]^2

At 25°C, we can assume that the concentration of water is 55.6 M (the density of water is 1 g/mL, and the molar mass of water is 18 g/mol), so:

K1 = (1.0×10^-7)^2/(55.6)^2 = 1.8×10^-16

Now we can use the van't Hoff equation to find the equilibrium constant at 52°C (325 K):

ln(K2/K1) = -(ΔH°/R)[(1/T2) - (1/T1)]

ln(K2/1.8×10^-16) = -(5.58×10^4 J/mol)/(8.314 J/(mol·K))[1/325 K - 1/298 K]

ln(K2/1.8×10^-16) = 17.49

K2/1.8×10^-16 = e^17.49

K2 = 2.6×10^-1

Finally, we can use the equilibrium constant to calculate kw at 52°C:

kw = [H3O+][OH-] = K[H2O]^2

kw = (2.6×10^-1)(55.6)^2

kw = 8.3×10^-12

Therefore, the value of kw at 52°C is 8.3×10^-12.

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Which one of the following statements about amorphous ceramics and crystalline ceramics is not correct? .Amorphous ceramics has low melting temperature, while crystalline ceramics has high melting temperature .Processing crystalline ceramics is very similar to processing powder metal components .Amorphous Ceramics have higher melting temperature, while crystalline ceramics have lower melting temperature

Answers

The statement that is not correct about amorphous ceramics and crystalline ceramics is: "Amorphous Ceramics have higher melting temperature, while crystalline ceramics have lower melting temperature."

Amorphous ceramics typically have lower melting temperatures compared to crystalline ceramics because of their disordered atomic structure, which requires less energy to break their bonds. Crystalline ceramics, on the other hand, have a well-ordered atomic structure, resulting in higher melting temperatures due to the need for more energy to break the stronger bonds.

The incorrect statement is the one suggesting that amorphous ceramics have a higher melting temperature than crystalline ceramics. In reality, amorphous ceramics generally have a lower melting temperature than their crystalline counterparts.

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at what temperature teq do the forward and reverse corrosion reactions occur in equilibrium? express your answer as an integer and include the appropriate units.

Answers

At 5363. 2 K  temperature, Teq, do the forward and reverse corrosion reactions occur in equilibrium .

1. DG = DH-TDS

= -3352 - 298 × -625.1 = 3165.7202 KJ

both DH,DS is negative so that for spontaneous process T<DH/DS

T = 3352/0.625

               = 5363.2 K

at 5363.2 K in equilibrium corrosion occur in reverse and forward .

What is corrosion's reverse process?

The reverse process of metallurgy is corrosion. To put it another way, when metal is exposed to oxygen and water, the energy that was used to transform ore into metal is reversed. Metal, ceramic, or polymer corrosion is an irreversible interracial reaction between a material and its environment that either consumes the material or dissolves a component of the environment into the material.

What is the balance of an opposite response?

A reaction that can be reversed can move in either the forward or backward directions. The rate of the forward reaction and the rate of the reverse reaction are in equilibrium. All reactant and item fixations are consistent at balance.

Incomplete question :

At what temperature, Teq, do the forward and reverse corrosion reactions occur in equilibrium? The chemical reaction that causes aluminum to corrode in air is given  4Al+3O₂?2Al₂O₃ in which at 298 K

?Hrxn?            = ?3352 kJ

?Srxn               = ?625.1 J/K

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using the equation c6h6 cl2-->c6h5cl hcl, what is the theoretical yield of c6h5cl if 91.2 g of c6h6 react?

Answers

The theoretical yield of C₆H₅Cl if 91.2 g of C₆H₆ react in the reaction given is 131.287 g.

Theoretical yield is the amount of a product that results from the full conversion of the limiting reactant in a chemical reaction. You won't get the same quantity of product from a laboratory reaction as you would from a perfect (theoretical) chemical reaction. Grammes or moles are common units of measurement for theoretical yield.

The amount of product created by a reaction is known as the actual yield, as opposed to theoretical yield. Because of a later reaction producing additional product or because the recovered product contains impurities, an actual yield may be larger than a theoretical yield.

Write the balanced equation-

C₆H₆ + Cl2 ⇒ C₆H₅Cl + HCl

1 mol C₆H₆ reacts with 1 mole Cl₂ to yield 1 mole of C₆H₅Cl

Calculate the moles of each reactant-

91.2 g C₆H₆ / 78.1 g/mol = 1.167 mol C₆H₆

36.9 g Cl2 / 70.9 g/mol = 0.520 mol Cl₂

1.167 mole C₆H₆ requires 0.520 mole Cl₂. You have excess Cl₂ so C₆H₆ is limiting.

1.167 mole C₆H₆ will yiels (at 100%) 1.167 mole C₆H₅Cl

1.167 mol x 112.5 g/mol = 131.287 g C₆H₅Cl

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PLEASE HELP!!!!!!

If 10.0 liters of ethane gas are used, how many liters of oxygen gas will be needed for the above reaction at STP?

2C2H6 (g) + 702(g) - 4C02(g) + 6H20 (g)
A 35.0 liters
B 2.85 liters
C 70.0 liters
D 1.4 liters

Answers

35 liters of oxygen gas will be needed for the reaction at STP and the correct option is option A.

STP stands for standard temperature and pressure. STP refers to a specific pressure and temperature used to report on the properties of matter.

According to IUPAC(International Union of Pure and Applied Chemistry), it is defined as -

Temperature of 0 degree celsius (273K)Pressure of 1 atm

It is generally needed to test and compare physical and chemical processes where temperature and pressure plays an important role as they keep on varying from one place to another.

One mole of a gas under STP conditions occupies a volume of 22.4L.

Given,

Volume of ethane = 10 L

We know that,

1 mole of a gas occupies 22.4 L of volume

so, 10 L is occupied by 10 / 22.4 = 0.446 moles of ethane

From the reaction, 2 moles of ethane use 7  moles of oxygen

so, 1 mole uses 7/2 = 3.5 moles of oxygen

0.446 moles will use 3.5 × 0.446 = 1.561 moles of oxygen

Volume occupied by oxygen = 1.561 × 22.4

= 35 L

Thus, the ideal selection is option A.

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Propose a structure for an amine of formula C4H9N, which liberates a gas when treated with NaNO2 and HCl. The 13C NMR spectrum is as follows, with attached protons in parentheses: ? 14(2), ? 34.3(2), ? 50.0(1).

Answers

Based on the given 13C NMR spectrum and the information about the liberation of gas upon treatment with [tex]NaNO_2[/tex] and HCl, a possible structure for the amine of formula [tex]C_4H_9N[/tex] is tert-butylamine.

The given 13C NMR spectrum indicates the presence of three different types of carbon atoms in the molecule. The chemical shift at δ 14 corresponds to a quaternary carbon, whereas the chemical shifts at δ 34.3 and δ 50.0 correspond to two different types of tertiary carbons. Based on the given information, a possible structure for the amine of formula [tex]C_4H_9N[/tex] could be tert-butylamine [tex](CH_3)_3CNH_2[/tex].

When tert-butylamine is treated with [tex]NaNO_2[/tex] and HCl, it liberates nitrogen gas ([tex]N_2[/tex]) due to the reaction of [tex]NaNO_2[/tex] with the amine group. The chemical shift at δ 14 corresponds to the quaternary carbon in the tert-butyl group, whereas the chemical shifts at δ 34.3 and δ 50.0 correspond to the two different types of tertiary carbons in the molecule.

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The correct question is:

Propose a structure for an amine of formula [tex]C_4H_9N[/tex], which liberates a gas when treated with [tex]NaNO_2[/tex] and HCl. The 13C NMR spectrum is as follows, with attached protons in parentheses: δ 14(2), δ 34.3(2), δ 50.0(1).

what is e at 25°c for the reaction?

Answers

The ΔG in kJ at 25∘C is −422.83kJ. To calculate the change in Gibbs free energy (ΔG) for the given reaction at 25°C, we will use the Nernst equation.

It is given by ΔG = -nFE₀

where:
- ΔG is the change in Gibbs free energy (in J)
- n is the number of electrons transferred (in moles)
- F is the Faraday constant, approximately 96,485 C/mol
- E₀ is the standard cell potential (in V)

First, identify the number of electrons transferred (n) in the balanced reaction:
Cr(s) + 3Ag⁺(aq) → 3Ag(s) + Cr³⁺(aq)

In this reaction, Chromium (Cr) loses 3 electrons (oxidation) and each Silver ion (Ag⁺) gains 1 electron (reduction), for a total of 3 electrons transferred.

Now, plug the values into the Nernst equation:
ΔG = - (3 mol e⁻) (96,485 C/mol e⁻) (1.50 V)
ΔG = -434,182.5 J

Since we want the answer in kJ, divide by 1000:
ΔG = -434.18 kJ (approximately)

Thus, the closest answer to this value among the provided options is (d) -422.83 kJ.

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The full question is:

The E∘ at 25∘C for the following reaction at the indicated concentration is 1.50 V. Calculate the ΔG in kJ at 25∘C : Cr(s) + 3Ag⁺(aq,0.1M) → 3Ag(s) + Cr³⁺(aq,0.1M)

a. -140.94

b. -295

c. -212

d. −422.83kJ

when ice I placed in a beaker that is the heated up very slowly at a constant heat, while it is stripped thoroughly,​

Answers

When ice is placed in a beaker and heated up slowly at a constant heat while being stirred thoroughly, it undergoes a phase change from solid to liquid, and the temperature remains constant during the melting process due to the energy being used to overcome intermolecular forces.

When ice is placed in a beaker and heated up slowly at a constant heat while being stirred thoroughly, it undergoes a phase change from solid to liquid. This process is known as melting and requires the absorption of energy, which is supplied by the heat source. As the ice melts, its temperature remains constant until all the ice has melted, after which the temperature of the water starts to increase.
The reason why the temperature of the melting ice remains constant during the phase change is due to the energy being used to overcome the intermolecular forces that hold the water molecules together in a solid crystal lattice. Once these forces are overcome, the energy supplied by the heat source can be used to increase the kinetic energy of the water molecules and raise their temperature.
It is important to heat the ice slowly and constantly while stirring thoroughly to ensure that the heat is evenly distributed throughout the beaker and that the ice melts uniformly. Rapid heating or uneven heating can cause the ice to melt unevenly, leading to the formation of water pockets and potential safety hazards.
In conclusion, when ice is placed in a beaker and heated up slowly at a constant heat while being stirred thoroughly, it undergoes a phase change from solid to liquid, and the temperature remains constant during the melting process due to the energy being used to overcome intermolecular forces.

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Write balanced molecular and net ionic equation for the following reaction and identify the gas formed: solid cadmium sulfide reacts with an aqueous solution of sulfuric acid. Identify all of the phases

Answers

The balanced molecular equation for the reaction between solid cadmium sulfide (CdS) and sulfuric acid (H2SO4) can be written as:

CdS(s) + H2SO4(aq) -> CdSO4(aq) + H2S(g)

In this equation, the phases are denoted by (s) for solid, (aq) for aqueous, and (g) for gas.

The net ionic equation for the reaction, which shows only the species that participate in the chemical change, can be obtained by omitting the spectator ions. In this case, the spectator ion is Cd2+ from the CdSO4(aq). The net ionic equation is:

H2SO4(aq) + H2S(aq) -> 2H2O(l) + S(g)

The gas formed in this reaction since solid cadmium sulfide (CdS) is a reactant, does not appear in the net ionic equation as it does not dissociate in the aqueous solution. Here's the correct net ionic equation for the reaction between solid cadmium sulfide and sulfuric acid:

H2SO4(aq) + CdS(s) → CdSO4(aq) + H2S(g)

In this equation, the gas formed is hydrogen sulfide (H2S). The phases are denoted by (s) for solid, (aq) for aqueous, and (g) for gas.

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What mass of aluminum metal can be produced by electrolysis of aluminum nitrate by a current of 1.5 amp in 2.5 hours? 1.3 g 3.8 g 0.047 g D. 0.14 g

Answers

The amount of aluminum produced by electrolysis can be calculated using Faraday's law, which relates the amount of substance produced to the amount of electric charge passed through the system. The correct answer is b.

The formula for this calculation is:

mass (g) = (current (A) x time (s) x atomic weight) / (faraday's constant x charge on an electron)

Using the values given in the question, we can calculate the mass of aluminum produced as:

mass = (1.5 A x 2.5 hours x 27 g/mol) / (96500 C/mol x 1.602 x 10^-19 C/electron)

mass ≈ 3.8 g

Therefore, the correct answer is b.

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--The complete Question is, What mass of aluminum metal can be produced by electrolysis of aluminum nitrate by a current of 1.5 amp in 2.5 hours?

a.1.3 g

b.3.8 g

c. 0.047 g

d. 0.14 g--

Calculate the solubility of Pb(IO3)2 solution in which the concentration of IO3- is 0. 015 M. Ksp for Pb(IO3)2 = 3. 2 x 10-13.

Select one:

Answers

The solubility of Pb(IO₃)₂ in a solution with IO₃- concentration of 0.015 M is 1.12 x 10⁻⁴ M.

The solubility of Pb(IO₃)₂ can be calculated using the Ksp expression:

Ksp = [Pb2+][IO₃-]₂

We are given the Ksp value as 3.2 x 10⁻¹³ and the concentration of IO₃- as 0.015 M. Let x be the solubility of Pb(IO₃)₂ in moles per liter.

At equilibrium, the concentration of Pb² and IO₃- in the saturated solution will be equal to x. Therefore, we can write:

Ksp = [Pb2+][IO₃-]₂ = x * (2x)² = 4x³

Substituting the given values, we get:

3.2 x 10⁻¹³ = 4x³

Solving for x, we get:

x = (3.2 x 10⁻¹³ / 4)^(1/3) = 1.12 x 10⁻⁴ M

Therefore, the solubility of Pb(IO₃)₂ in a solution with IO₃- concentration of 0.015 M is 1.12 x 10⁻⁴ M.

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when the change in free eneergy for a reaction is positive the correct statement for the equilbrium constant Keq: a. Keq = 1. b. Keq > 1. c. Keq < 1

Answers

When the change in free energy for a reaction is positive, it means that the reaction is non-spontaneous and requires energy to proceed. In terms of the equilibrium constant (Keq), this indicates that the products of the reaction are less favored than the reactants at equilibrium.

Therefore, the correct statement for Keq would be c. Keq < 1.  Keq is the ratio of the concentrations of products to reactants at equilibrium. If Keq is less than 1, it means that the concentration of reactants is greater than the concentration of products at equilibrium. This is consistent with a non-spontaneous reaction since the system will tend to favor the reactants over the products. On the other hand, if Keq is greater than 1, it means that the concentration of products is greater than the concentration of reactants at equilibrium. This is consistent with a spontaneous reaction since the system will tend to favor the products over the reactants. Finally, if Keq is equal to 1, it means that the concentrations of products and reactants are equal at equilibrium, indicating a balanced system where neither the reactants nor products are favored.

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will the bond length in a cation be higher or lower than a ground state

Answers

The bond length in a cation can vary depending on the specific situation. In general, the bond length in a cation tends to be shorter than the bond length in the ground state due to the loss of an electron.

When an atom loses an electron to become a cation, it becomes positively charged, and the remaining electrons are held more tightly to the nucleus. This stronger attraction between the positively charged nucleus and the remaining electrons leads to a shorter bond length.

However, there are exceptions to this general rule, and the bond length in a cation can sometimes be longer than the bond length in the ground state. This can occur when the cation is in a highly excited state, or when the cation is interacting with other molecules or ions in a complex system.

So, in summary, the bond length in a cation can be higher or lower than the bond length in the ground state, depending on the specific circumstances.

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for all adiabatic processes:the entropy does not changethe entropy increasesthe entropy decreasesthe entropy does not increasethe entropy does not decrease

Answers

For all adiabatic processes, the entropy does not change.

This is because adiabatic processes are defined as processes where no heat is exchanged between the system and its surroundings. Since entropy is a measure of the amount of energy that is unavailable to do work, and heat is a form of energy, if no heat is exchanged, then the entropy of the system remains constant.

It's important to note, however, that this only applies to adiabatic processes. In general, the entropy of a closed system tends to increase over time due to various irreversible processes, as described by the second law of thermodynamics.

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what is the mass of barium hydroxide (171.35 g/mol) dissolved in 0.500 l of 0.100 m ba(oh)2 solution?

Answers

The mass of barium hydroxide (Ba(OH)2) dissolved in 0.500 L of 0.100 M Ba(OH)2 solution is 8.5675 grams.

To calculate the mass of barium hydroxide dissolved in the solution, we need to use the equation:

Mass = Concentration (Molarity) x Volume x Molecular Weight

Molecular weight of Ba(OH)2 = 171.35 g/mol

Volume = 0.500 L

Concentration (Molarity) = 0.100 M

First, let's calculate the number of moles of Ba(OH)2 in the solution:

Number of moles = Concentration x Volume

Number of moles = 0.100 mol/L x 0.500 L

Number of moles = 0.050 mol

Now, we can calculate the mass of Ba(OH)2 using the formula mentioned earlier:

Mass = Number of moles x Molecular weight

Mass = 0.050 mol x 171.35 g/mol

Mass = 8.5675 grams

The mass of barium hydroxide (Ba(OH)2) dissolved in 0.500 L of 0.100 M Ba(OH)2 solution is 8.5675 grams.

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What is the ratio of the probability of finding a molecule moving with the average speed to the probability of finding a molecule moving with 3 times the average speed? How does this ratio depend on temperature?

Answers

The ratio of the probability of finding a molecule moving with the average speed to the probability of finding a molecule moving at 3 times the average speed depends on the Maxwell-Boltzmann distribution.

This distribution describes the probability of a molecule having a specific speed based on temperature and molecular mass. The ratio of these probabilities can be expressed as P(v)/P(3v), where P(v) represents the probability of a molecule moving at average speed and P(3v) represents the probability of a molecule moving at 3 times the average speed. As temperature increases, the Maxwell-Boltzmann distribution becomes wider, and the peak shifts towards higher speeds. This means that at higher temperatures, the probability of finding a molecule moving at 3 times the average speed will increase compared to lower temperatures. Therefore, the ratio P(v)/P(3v) will decrease with increasing temperature.

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what is the stereochemical relationship between the salts formed by tartaric acid

Answers

Tartaric acid has two chiral centers, and therefore can exist as four possible stereoisomers: meso-tartaric acid, D-tartaric acid, L-tartaric acid, and DL-tartaric acid. Meso-tartaric acid is not optically active because it has a plane of symmetry that divides the molecule into two mirror-image halves.

This means that it is achiral and does not rotate plane-polarized light. D- and L-tartaric acid are enantiomers, which means that they are non-superimposable mirror images of each other. They rotate plane-polarized light in opposite directions and have identical physical properties except for their effect on plane-polarized light. DL-tartaric acid is a racemic mixture of the D- and L-tartaric acid enantiomers and is optically inactive.

When tartaric acid is deprotonated, it forms a salt with a cation such as sodium or potassium. The stereochemistry of the salt depends on the stereochemistry of the tartaric acid used to form it. For example, if D-tartaric acid is used, the resulting salt will have the same absolute configuration as the D-tartaric acid molecule. The same is true for L-tartaric acid. The meso-tartaric acid can form a salt with either D or L tartaric acid and the product is called a racemic salt.

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for the reaction given in part a, δs∘rxn is 33.0 j/k . what is the standard gibbs free energy of the reaction, δg∘rxn ? express your answer numerically in kilojoules.

Answers

The standard Gibbs free energy change of the reaction is 0.04 kJ/mol, which can be expressed numerically as 0.04 kJ.

\We can use the relationship between Gibbs free energy change, enthalpy change, and entropy change to solve for the standard Gibbs free energy change of the reaction:

ΔG° = ΔH° - TΔS°

where ΔH° is the standard enthalpy change of the reaction, ΔS° is the standard entropy change of the reaction, T is the temperature in Kelvin, and ΔG° is the standard Gibbs free energy change of the reaction.

We are given that ΔS° = 33.0 J/K. However, we need to convert this to kJ/K, since the units of ΔG° are kJ/mol:

ΔS° = 33.0 J/K * (1 kJ/1000 J) = 0.033 kJ/K

We are not given the value of ΔH°, so we cannot calculate ΔG° directly. However, we can use the fact that at equilibrium, ΔG° = 0. This allows us to set up the equation:

0 = ΔH° - TΔS°

Solving for ΔH°, we get:

ΔH° = TΔS° = (298 K) * (0.033 kJ/K) = 9.87 kJ/mol

Therefore, the standard enthalpy change of the reaction is 9.87 kJ/mol. To calculate the standard Gibbs free energy change of the reaction, we can substitute the values into the equation:

ΔG° = ΔH° - TΔS°

= (9.87 kJ/mol) - (298 K)(0.033 kJ/K)

= 9.87 kJ/mol - 9.83 kJ/mol

= 0.04 kJ/mol

Therefore, the standard Gibbs free energy change of the reaction is 0.04 kJ/mol, which can be expressed numerically as 0.04 kJ.

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How many mL of 2.5 M HCI are required to neutralize 15 mL of 5.0 M NaOH?

Answers

To determine the amount of HCl required to neutralize 15 mL of 5.0 M NaOH, we need to use the equation: M1V1 = M2V2, 30 mL of 2.5 M HCl is required to neutralize 15 mL of 5.0 M NaOH.

To determine the amount of HCl required to neutralize 15 mL of 5.0 M NaOH, we need to use the equation:

M1V1 = M2V2

where M1 is the molarity of the acid, V1 is the volume of the acid, M2 is the molarity of the base, and V2 is the volume of the base.

In this case, we know that the molarity of NaOH is 5.0 M, the volume of NaOH is 15 mL, and we want to find the volume of HCl required to neutralize it, which we'll call V1.

First, we need to calculate the number of moles of NaOH:

5.0 M * 0.015 L = 0.075 moles NaOH

Since HCl and NaOH react in a 1:1 ratio, we know that we'll need 0.075 moles of HCl to neutralize the NaOH.

Next, we need to find the volume of 2.5 M HCl that contains 0.075 moles of HCl:

2.5 M = 2.5 moles/L

0.075 moles / 2.5 moles/L = 0.03 L = 30 mL

Therefore, 30 mL of 2.5 M HCl is required to neutralize 15 mL of 5.0 M NaOH.

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4.68 l of n2(g) is mixed with 3.79 l of h2(g) and reacts with 100% yield. what volume of nh3(g) is produced? assume all gases are at the same temperature and pressure.

Answers

The volume of [tex]NH_3[/tex] produced is 7.55 L, assuming constant temperature and pressure. [tex]H_2[/tex] is the limiting reactant, and all of it will be consumed in the reaction, producing 0.338 moles of [tex]NH_3[/tex].

The balanced equation for the reaction between nitrogen gas and hydrogen gas to form ammonia gas is:

[tex]$N_{2(g)} + 3H_{2(g)} \rightarrow 2NH_{3(g)}}$[/tex]

From the equation, we see that 1 mole of [tex]N_2[/tex] reacts with 3 moles of [tex]H_2[/tex] to produce 2 moles of [tex]NH_3[/tex]. Therefore, we need to determine the limiting reactant to calculate the volume of [tex]NH_3[/tex] produced.

To do this, we can use the ideal gas law, which states that the number of moles of a gas is directly proportional to its volume, assuming constant temperature and pressure. Therefore, we can convert the given volumes of [tex]N_2[/tex] and [tex]H_2[/tex] to moles and compare their ratios to determine the limiting reactant.

Using the ideal gas law, we can calculate the number of moles of [tex]N_2[/tex]:

[tex]$n(N_2) = \dfrac{V(N_2)}{V_m(N_2)}$[/tex]

[tex]$n(H_2) = \dfrac{V(H_2)}{V_m(H_2)}$[/tex]

Substituting the given values into these equations, we get:

[tex]n(N_2)[/tex] = 4.68 L / 22.4 L/mol = 0.209 moles

[tex]n(H_2)[/tex] = 3.79 L / 22.4 L/mol = 0.169 moles

Since the stoichiometric ratio of [tex]N_2[/tex] to [tex]H_2[/tex] is 1:3, we can see that [tex]H_2[/tex] is the limiting reactant, as we only have 0.169 moles of [tex]H_2[/tex], which is less than the amount required to react with all of the [tex]N_2[/tex] (0.209 moles). Therefore, all of the [tex]H_2[/tex] will be consumed in the reaction, and we can calculate the volume of [tex]NH_3[/tex] produced using the number of moles of [tex]NH_3[/tex] formed, which is twice the number of moles of [tex]H_2[/tex] consumed:

[tex]$n(NH_3) = 2 \times n(H_2) = 2 \times 0.169 , \text{moles} = 0.338 , \text{moles}$[/tex]

Using the ideal gas law again, we can calculate the volume of [tex]NH_3[/tex]:

[tex]$V(NH_3) = n(NH_3) \times V_m(NH_3)$[/tex]

where Vm([tex]NH_3[/tex]) is the molar volume of [tex]NH_3[/tex] at the same temperature and pressure.

Substituting the given values, we get:

[tex]V(NH_3)[/tex] = 0.338 moles x 22.4 L/mol = 7.55 L

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