Answer:
Vapor pressure of water = 23.14torr
Explanation:
When you made a solution, vapor pressure decreases following Raoult's law:
[tex]P_{solution} = X_{solvent} P_{solvent}[/tex]
Where P is vapor pressure and X mole fraction
As vapor pressure of water is 23.77torr we must find the mole fraction of water knowing the solution is 1.500m glucose (That is 1.500 moles of glucose per kg of water = 1000g of water).
1000g of H₂O are, in moles (Molar mass: 18.02g/mol):
1000g H₂O ₓ (1mole / 18.02g) = 55.5 moles of H₂O.
As we know now the solution contains 55.5 moles of water and 1.5 moles of glucose. Thus, mole fraction of water (Solvent) is:
[tex]X_{H_2O} = \frac{55.5molesH_2O}{55.5molesH_2O + 1.5 molesGlucose} = 0.9737[/tex]
Replacing in Raoult's law, pressure of water above the solution is:
[tex]P_{solution} = X_{solvent} P_{solvent}[/tex]
[tex]P_{solution} = 0.9737*23.77torr[/tex]
Vapor pressure of water = 23.14torrThe table below shows the electronegativity values of various elements on the periodic table. Electronegativities A partial periodic table. Which pair of atoms would form a covalent bond ? calcium (Ca) and bromine (Br) rubidium (Rb) and sulfur (S) cesium (Cs) and nitrogen (N) oxygen (O) and chlorine (Cl)
Answer:
Oxygen and Chlorine
Explanation:
Covalent bonds involve the sharing of electrons between nonmetals.
Answer:
oxygen (O) and chlorine (Cl)
Explanation:
cuz i said so
True or False
1. Density is considered a chemical (i.e., not a physical) property. TRUE FALSE
2. When naming an ionic compound containing a transition element such as iron (Fe), the name must include a Roman numeral to indicate the charge of the metal ion. TRUE FALSE
3. The neutron was discovered about 20 years after the electron and proton because it has no charge (in order for it to be detected). TRUE FALSE
4. When we balance a chemical equation, we are observing the law of conservation of mass as well as the part of Dalton’s theory that atoms are neither created or destroyed in a chemical reaction TRUE FALSE
5. When a gas is heated up in a closed container, the kinetic energy of the molecules or atoms of the gas increase, which leads to a decrease in the pressure of the gas. TRUE FALSE
6. The amount of enthalpy (heat energy) for a reaction is directly proportional to the amount (number of moles or grams) of the reactants. TRUE FALSE
7. The combined gas law works for any gas (i.e., you do not need to know the chemical formula). TRUE FALSE
8. A balloon with 10.0 g of CO2 gas will have more molecules than a 10.0 g sample of NO gas. TRUE FALSE
9. Unless a sample is at absolute zero (kelvins), the particles in the sample will have kinetic energy and have some kind of motion. TRUE FALSE
Answer:
1. False
2. True
3. True
4. True
5. True
6. True
7. True
8. False
9. True
Explanation:
Density is a physical property since its measurement does not involve any chemical process.
Since transition elements exhibit variable oxidation states, the actual oxidation state of the transition element must be specified in the compound.
Due to the fact that neutron has no charge, it was discovered by Chadwick long after the electron and proton were discovered.
The balancing of chemical reaction equations is a demonstration that atoms are neither created no destroyed. It also shows that mass is neither created nor destroyed in chemical reactions.
When a gas is heated, it expands. Its volume and its kinetic energy increases. Since volume and pressure are inversely proportional (Boyle's law) the pressure decreases.
Enthalpy is said to be an extensive property. This implies that the magnitude of change in enthalpy is known to depend on the amount of reactants that is actually reacted.
The combined gas law is applicable to all ideal gas systems irrespective of their individual chemical formulas.
10g of CO2 contains 0.227 moles of CO2 while 10g of NO contains 0.33 moles of NO hence 10.0 g of NO will contain more molecules than 10.0g of CO2.
If a sample is not at absolute zero, the particles are known to possess kinetic energy which decreases continuously until absolute zero is attained.
When hydrogenation of two alkenes produce the same alkane, the more stable alkene has the___________ smaller heat of hydrogenation.
Explanation:
Heat of hydrogenation of alkenes is a measure of the stability of carbon-carbon double bonds.
In general, the lower the value of the heat of hydrogenation the more stable the double bond of the alkene.
Also, heat of hydrogenation of alkenes always have a negative value.
What is the molar mass of a protein if a solution of 0.020 g of the protein in 25.0 mL of solution has an osmotic pressure of 0.56 torr at 25 ∘ C
Answer:
26.5 kD
Explanation:
Here we can apply the formula ∏ = iMRT, where ∏ = osmotic pressure = 0.56 - ( given ). This is only one part of the information we are given / can conclude in this case ....
i = van’t Hoff factor = 1 for a protein molecule,
R = gas constant = 62.36 L torr / K-mol,
T ( temperature in Kelvin ) = 25 + 273 - conversion factor C° + 273 = 298K
( Known initially ) ∏ = osmotic pressure = 0.56 torr
..... besides the part " M " in the formula, which we have no information on whatsoever, as we have to determine it's value.
_____
Substitute derived / known values to solve for M ( moles / liter ) -
∏ = iMRT
⇒ 0.56 = ( 1 )( M )( 62.36 )( 298 )
⇒ 0.56 = M( 18583.28 )
⇒ M = 0.56 / 18583.28 ≈ 0.00003013461 ....
_____
We know that M = moles / liter, so we can use this to solve for moles, and hence calculate the molar mass by the formula molar mass = g / mol -
M = mol / l
⇒ 0.00003013461 = 0.020 / 25 mL ( 0.025 L ),
0.020 / 0.025 = 0.8 g / L
⇒ 0.8 g = 0.00003013461 moles,
molar mass = 0.8 g / 0.00003013461 moles = 26,548 g / mol = 26.5 kD
What's the difference between velocity time graph and distance time graph
Explanation:
Hi there!
I attached a photo of a unit summary that states the difference between s-t and v-t graph.
Hope this helps ;) ❤❤❤
How many mL of calcium hydroxide are required to neutralize 25.0 mL of 0.50 M
nitric acid?
Answer:
6.5 mL
Explanation:
Step 1: Write the balanced reaction
Ca(OH)₂ + 2 HNO₃ ⇒ Ca(NO₃)₂ + 2 H₂O
Step 2: Calculate the reacting moles of nitric acid
25.0 mL of 0.50 M nitric acid react.
[tex]0.0250L \times \frac{0.50mol}{L} = 0.013 mol[/tex]
Step 3: Calculate the reacting moles of calcium hydroxide
The molar ratio of Ca(OH)₂ to HNO₃ is 1:2. The reacting moles of Ca(OH)₂ are 1/2 × 0.013 mol = 6.5 × 10⁻³ mol
Step 4: Calculate the volume of calcium hydroxide
To answer this, we need the concentration of calcium hydroxide. Since the data is missing, let's suppose it is 1.0 M.
[tex]6.5 \times 10^{-3} mol \times \frac{1,000mL}{1.0mol} = 6.5 mL[/tex]
The following balanced equation describes the reduction of iron(III) oxide to molten iron within a blast furnace: Fe2O3(s) + 3CO(g) ---> 2Fe(l) + 3CO2(g) Steve inserts 450. g of iron(III) oxide and 260. g of carbon monoxide into the blast furnace. After cooling the pure liquid iron, Steve determines that he has produced 288g of iron ingots. What is the theoretical yield of liquid iron, in grams? Just enter a numerical value. Do not enter units.
Answer: 313.6
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} Fe_2O_3=\frac{450g}{160g/mol}=2.8moles[/tex]
[tex]\text{Moles of} CO=\frac{260g}{28g/mol}=9.3moles[/tex]
[tex]Fe_2O_3(s)+3CO(g)\rightarrow 2Fe(l)+3CO_2(g)[/tex]
According to stoichiometry :
1 mole of [tex]Fe_2O_3[/tex] require 3 moles of [tex]CO[/tex]
Thus 2.8 moles of [tex]Fe_2O_3[/tex] will require=[tex]\frac{3}{1}\times 2.8=8.4moles[/tex] of [tex]CO[/tex]
Thus [tex]Fe_2O_3[/tex] is the limiting reagent as it limits the formation of product and [tex]CO[/tex] is the excess reagent.
As 1 mole of [tex]Fe_2O_3[/tex] give = 2 moles of [tex]Fe[/tex]
Thus 2.8 moles of [tex]Fe_2O_3[/tex] give =[tex]\frac{2}{1}\times 2.8=5.6moles[/tex] of [tex]Fe[/tex]
Mass of [tex]Fe=moles\times {\text {Molar mass}}=2.6moles\times 56g/mol=313.6g[/tex]
Theoretical yield of liquid iron is 313.6 g
Please help asap! Giving brainliest.
What is the total number of electrons that can occupy the p sublevel? (3 points)
Select one:
a. 2 electrons
b. 6 electrons
c. 8 electrons
d. 10 electrons
Answer:
The answer is 6 because the p sublevel holds 3 orbitals and since each orbital can hold 2 electrons, the answer is 3 * 2 = 6.
Answer:
6 electrons
Explanation:
Each principal energy level above the first contains one s orbital and three p orbitals. A set of three p orbitals, called the p sublevel, can hold a maximum of six electrons. So the answer is 6 electrons.
What does the state symbol (aq) mean when written after a chemical
compound in a chemical equation?
A. It means the compound is in the liquid phase.
B. It means the compound is dissolved in water.
C. It means the compound is in the gas phase.
D. It means the compound is in the solid phase.
B. it means the compound is dissolved in water
Answer:
b
Explanation:
a p e x :)
Identify each reaction from the citric acid cycle as an oxidation‑reduction reaction, an esterification reaction, an amidation reaction, a hydrolysis reaction, a hydration reaction, or a dehydration reaction.
1. Which type of reaction occurs when succinyl-CoA is converted to succinate in the citric acid cycle?
2. Which type of reaction occurs when malate is converted to oxaloacetate in the citric acid cycle?
3. Which type of reaction occurs when aconitate is converted to isocitrate in the citric acid cycle?
Answer:
1. Oxidation-reduction and hydrolysis
2. Oxidation-reduction
3. Dehydration
Explanation:
Our options for each reaction are:
a) Oxidation‑reduction reaction
b) Esterification reaction
c) Amidation reaction
d) Hydrolysis reaction
c) Hydration reaction
f) Dehydration reaction
In reaction one the have the rupture of the S-CoA bond. This reaction takes place by the addition of a water molecule and the oxidation to a carboxylic acid group. So, for reaction 1 we will have an oxidation-reduction and a hydrolysis reaction.
For reaction 2, the functional group change from alcohol to a carboxylic acid. So, we have an oxidation-reduction reaction.
In the last reaction, we have the production of a double bond by the removal of water. With this in mind, we have a dehydration reaction.
See figure 1
I hope it helps
Osmosis is the process responsible for carrying nutrients and water from groundwater supplies to the upper parts of trees. The osmotic pressures required for this process can be as high as 19.1 atm . What would the molar concentration of the tree sap have to be to achieve this pressure on a day when the temperature is 32 ∘C ? Express your answer to three significant figures and include the appropriate units. View Available Hint(s)
Answer:
[tex]M=0.763\frac{mol}{L}=0.763M[/tex]
Explanation:
Hello,
In this case, as the osmotic pressure (π) is widely known as a colligative property, we can see that the solution in this case is formed by water and tree sap, that is mathematically defined by:
[tex]\pi =iMRT[/tex]
Thus, since tree sap is a covalent substance that is nonionizing, we can infer its van't Hoff factor to be 1, therefore, for the given osmotic pressure and temperature, we can compute the molar concentration (in molar units mol/L) as follows:
[tex]M=\frac{\pi }{RT} =\frac{19.1atm}{0.082\frac{atm*L}{mol*K}*(32+273.15)K} \\\\M=0.763\frac{mol}{L}=0.763M[/tex]
Best regards.
The migration of atoms or molecules through a material is called Choose one: biomineralization. precipitation from a gas. solidification of a melt. diffusion.
Answer:
diffusion
Explanation:
Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration in response to a concentration gradient. A concentration gradient simply means a difference in concentration.
Diffusion occurs in solids,liquids and gases. Diffusion is fastest in gases and slowest in solids. Diffusion of solid particles may take very many years while diffusion of gases takes a few milliseconds depending on the mass of the gas.
In materials, atoms and molecules also move from one part of the material to another. This is also refereed to as diffusion.
16. A metal element and a non-metal element are brought near each other and allowed to react. What's the most likely type of compound
that will form between these two elements?
A. lonic and covalent
B. lonic
C. Covalent
D. Neither, metals and non-metals don't react.
Answer:
B) Ionic
Explanation:
Suppose of nickel(II) iodide is dissolved in of a aqueous solution of potassium carbonate. Calculate the final molarity of nickel(II) cation in the solution. You can assume the volume of the solution doesn't change when the nickel(II) iodide is dissolved in it. Round your answer to significant digits.
Answer:
0.619 M to 3 significant figures.
Explanation:
1 mole of [tex]NiI_{2}[/tex] - 312.5 g
? mole of [tex]NiI_{2}[/tex] - 2.9 g
= 2.9/312.5
= 0.0928 moles.
Concentration = no. of moles/vol in litres = [tex]\frac{0.0928}{0.150L}[/tex]
= 0.619 M
A 1.0 kg object absorbs 1,303 J of heat energy and experiences a temperature increase of 5.2∘C. What is the object’s specific heat, in joules per gram-degree celsius? Report your answer with the correct number of significant figures.
Answer:
c = 250.58 J/kg/[tex]^{0}C[/tex]
Explanation:
The specific heat of a substance is the required quantity of heat to increase or decrease the temperature of its unit mas by 1 kelvin.
Q = mcΔθ
where: Q is the quantity of heat absorbed or released, m is the mass of the substance, c is its specific heat and Δθ is the change in temperature of the substance.
Given that; m = 1.0 kg, Q = 1303 J and Δθ = 5.2 [tex]^{0}C[/tex], then;
c = Q ÷ (mΔθ)
= 1303 ÷ (1.0 × 5.2)
= 1303 ÷ 5.2
= 250.58 J/kg/[tex]^{0}C[/tex]
The specific heat of the object is 250.58 J/kg/[tex]^{0}C[/tex].
Answer:
0.25
Explanation:
Which of the following properties should carbon (C) have based on its position on
the periodic table?
A. Shiny
B. Dense
C. Malleable
D. Poor conductor
Answer:
D- poor conductor
Explanation:
metallic properties decrease as we go on the right of the periodic table. Carbon is a non metal hence it is dull and a poor conductor.
it has a low density and is ductile.
Answer: Poor conductor
Explanation:
Calculate the amount of energy absorbed by 45.0 g sample of water to raise its temperature from 18.0C to 48.0 C. The specific heat of water is 4.18 J/g C. 1000 J= 1kj
Answer:
5.643 kJ
Explanation:
The quantity of heat released or absorbed by a substance (Q) is given by the equation:
Q = mcΔT
Where m is the mass of the substance, c is the specific heat of substance and ΔT is the difference between the final temperature and the initial temperature.
Given that:
m = 45 g, Final temperature = 48°C, Initial temperature = 18°C, c = specific heat of water = 4.18 J/g°C
ΔT = Final temperature - Initial temperature = 48°C - 18°C = 30°C
The quantity of heat is:
Q = mcΔT = 45 g × 4.18 J/g°C × 30°C = 5643 J
Q = 5.643 kJ
The specific heat of a certain type of metal is 0.128 J/(g⋅∘C). What is the final temperature if 305 J of heat is added to 52.4 g of this metal, initially at 20.0 ∘C?
Answer:
65.47∘C
Explanation:
Specific heat capacity, c = 0.128 J/(g⋅∘C)
Initial temperature = 20.0 ∘C
Final temperature = ?
Mass = 52.4 g
Heat = 305 J
All these variables are related by the following equation;
H = m c ΔT
ΔT = H / mc
ΔT = 305 / (52.4 * 0.128)
ΔT = 45.47∘C
ΔT = Final Temperature - Initial Temperature
Final temperature = ΔT + Initial temperature
Final temperature = 45.47∘C + 20.0 ∘C = 65.47∘C
Treatment of 1 mole of dimethyl sulfate with 2 moles of sodium acetylide results in the formation of propyne as the major product.
A) Draw a reasonable mechanism accounting for the formation of the byproduct 2-butyne.
B) 2-Butyne is observed as a minor product of this reaction. Draw a mechanism accounting for the formation of this minor product and explain how your proposed mechanism is consistent with the observation that acetylene is present among the reaction products.
C) Predict the major and minor products that are expected if diethyl sulfate is used in place of dimethyl sulfate.
Answer:
(a) appended underneath is the inorganic ion shaped in the reaction and the mechanism of its formation
(b) 2-butyne framed as a minor product is appeared in the connection. It is shaped when the monosodium subordinate of dimethylsulphoxide gets a hydrogen from the propyne and reacts again with monosodium methylsulphoxide.
(c) The major product framed when diethylsulphoxide is utilized, would be butyne and minor product would be 3-hexyne.
Explanation:
attached below is diagram
A 0.500 g sample of tin (Sn) is reacted with oxygen to give 0.534 g of product. What is the percent mass of the tin and percent by mass of oxygen in the sample
Answer:
Percentage mass of Tin = 96.3%
Percentage mass of oxygen = 6.40%
Explanation:
The product of the reaction is an oxide of tin.
Assuming all of the 0.500 g sample of tin reacted with oxygen to produce the oxide:
Mass of oxide = 0.534 g
Mass of tin present in the oxide = 0.500 g
Mass of oxygen in the oxide = 0.534 g of oxide - 0.500 g Sn = 0.034 g O
Percentage composition = mass of element/mass of compound × 100%
Percentage composition of Sn = 0.500 g/0.534 g × 100 = 93.6% Sn
Percentage composition of oxygen = 0.034 g/0.534 g × 100 = 6.40%
4 Al + 3O2 → 2Al2O3 If 14.6 grams Al are reacted, how many liters of O2 at STP would be required?
Answer: 9.08 L
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}\times{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} Al=\frac{14.6g}{27g/mol}=0.54moles[/tex]
[tex]4Al+3O_2\rightarrow 2Al_2O_3[/tex]
According to stoichiometry :
4 moles of [tex]Al[/tex] require = 3 moles of [tex]O_2[/tex]
Thus 0.54 moles of [tex]Al[/tex] will require=[tex]\frac{3}{4}\times 0.54=0.405moles[/tex] of [tex]O_2[/tex]
Standard condition of temperature (STP) is 273 K and atmospheric pressure is 1 atm respectively.
According to the ideal gas equation:
[tex]PV=nRT[/tex]
P = Pressure of the gas = 1 atm
V= Volume of the gas = ?
T= Temperature of the gas = 273 K
R= Gas constant = 0.0821 atmL/K mol
n= moles of gas= 0.405
[tex]V=\frac{nRT}{P}=\frac{0.405\times 0.0821\times 273}{1}=9.08L[/tex]
Thus 9.08 L of [tex]O_2[/tex] at STP would be required
Considering the reaction stoichiometry and STP conditions, 9.072 L of O₂ at STP would be required.
The balanced reaction is:
4 Al + 3 O₂ → 2 Al₂O₃
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
Al: 4 moles O₂: 3 moles Al₂O₃: 2 moles
Being 27 g/mole the molar mass of Al, this is the amount of mass that a substance contains in one mole, then if 14.6 grams Al are reacted, the number of moles of Al that react is calculated as:
[tex]14.6 gramsx\frac{1 mole}{27 grams}= 0.54 moles[/tex]
Then you can apply the following rule of three: if by stoichiometry 4 moles of Al react with 3 moles of O₂, 0.54 moles of Al react with how many moles of O₂?
[tex]amount of moles of O_{2} =\frac{0.54 moles of Alx3 moles of O_{2} }{4 moles of Al}[/tex]
amount of moles of O₂= 0.405 moles
On the other side, the STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.
Then you can apply the following rule of three: if by definition of STP 1 mole of O₂ occupies 22.4 L, 0.405 moles of O₂, how much volume does it occupy?
[tex]volume=\frac{0.405 moles of O_{2}x22.4 L }{1 mole of O_{2} }[/tex]
volume= 9.072 L
Finally, 9.072 L of O₂ at STP would be required.
Learn more:
brainly.com/question/16487206?referrer=searchResults brainly.com/question/14446695?referrer=searchResults brainly.com/question/11564309?referrer=searchResults brainly.com/question/4025026?referrer=searchResults brainly.com/question/18650135?referrer=searchResultsDraw the curved arrow mechanism for the reaction between (2R,3R)-3,5-dimethylhexan-2-ol and PCl3.
Answer:
Sn2 mechanism
Explanation:
In this case, our nucleophile is the "OH" on (2R,3R)-3,5-dimethylhexan-2-ol. The alcohol group will attack the [tex]PCl_3[/tex] to produce a new bond between O and P with a positive charge in the oxygen. Additionally, when the OH attacks a Br atom leaves the molecule producing a bromide ion.
In the next step, the bromide ion produced will attack the carbon bonded to the OH that now is bonded to [tex]PCl_2[/tex]. An Sn2 reaction takes place and the substitution would be made in only one step. Due to this, we will have an inversion in the stereochemistry and the absolute configuration on carbon 2 will change from "R" to "S" to produce (2S,3R)-2-bromo-3,5-dimethylhexane.
I hope it helps!
All of the following reactions can be described as displacement reactions except:____________.
a.) Zn(s) + FeCl2(aq) → ZnCl2(aq) + Fe(s).
b.) C6H6(l) + Cl2(g) → C6H5Cl(l) + HCl(g).
c.) 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g).
d.) Cu(s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag(s).
e.) CuSO4(aq) + Fe(s) → Cu(s) + FeSO4(aq).
Answer:
b
Explanation:
The reaction that is not a displacement reaction from all the options is [tex]C_6H_6_{(l)} + Cl_{2(g)} --> C_6H_5Cl_{(l)} + HCl_{(g)}[/tex]
In a displacement reaction, a part of one of the reactants is replaced by another reactant. In single displacement reactions, one of the reactants completely displaces and replaces part of another reactant. In double displacement reaction, cations and anions in the reactants switch partners to form products.
Options a, c, d, and e involves the displacement of a part of one of the reactants by another reactant while option b does not.
Correct option = b.
The reaction given in Option A is not a displacement reaction. In Displacement reaction functional group of one reactant is replaced by the functional group of the another reactant.
Displacement reaction:
In this reaction functional group of one reactant is replaced by the functional group of the another reactant.
[tex]\bold { Zn(s) + FeCl_2(aq) \rightarrow ZnCl_2(aq) + Fe(s).}[/tex]
In the above reaction Zinc does not any functional group to exchange with iron chloride.
Therefore, the reaction given in Option A is not a displacement reaction.
To know more about Displacement reaction,
https://brainly.com/question/4339209
Draw the major product(s) obtained when the following compounds are treated with bromine in the presence of iron tribromide.
a. Bromobenzene
b. ortho-Xylene
c. Benzene sulfonic acid
d. Benzaldehyde
e. meta-Nitrotoluene
f, para-Dibromobenzene
g. Nitrobenzene tert-Butylbenzene
h. Benzoic acid
i. Dibromobenzene
Answer:
The halogens are the ortho and para directing groups. Whenever they react with other benzene compounds they will attach to the ortho or para positions of the benzene ring.
Major products which are obtained by reacting these given compounds are given in attached pictures with complete reactions.
HBr will always be the side product of the bromine reactions along with the major compound.
Explanation:
Give the name of the following molecule
Answer:
[tex]\boxed{Heptene}[/tex]
Explanation:
Double Bond => An Alkene molecule
So, the suffix will be "-ene"
7 Carbons => So, we'll use the prefix "Hept-"
Combining the suffix and prefix, we get:
=> Heptene
Answer:
[tex]\boxed{\mathrm{Heptene}}[/tex]
Explanation:
Alkenes have double bonds. The molecule has one double bond.
Suffix ⇒ ene
The molecule has 7 carbon atoms and 14 hydrogen atoms.
Prefix ⇒ Hept (7 carbons)
The molecule is Heptene.
[tex]\mathrm{C_7H_{14}}[/tex]
When 50.0 mL of 1.27 M of HCl(aq) is combined with 50.0 mL of 1.32 M of NaOH(aq) in a coffee-cup calorimeter, the temperature of the solution increases by 8.49°C. What is the change in enthalpy for this balanced reaction? HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) Assume that the solution density is 1.00 g/mL and the specific heat capacity of the solution is 4.18 J/g⋅°C. Hint: You need to determine the limiting reagent.
Answer:
-55.9kJ/mol is the change in enthalpy of the reaction
Explanation:
In the reaction:
HCl(aq) + NaOH(aq) → H₂O(l) + NaCl
Some heat is released per mole of reaction.
To know how many moles reacts we need to find limiting reactant:
Moles HCl = 0.050L ₓ (1.27mol / L) = 0.0635 moles HCl
Moles NaOH = 0.050L ₓ (1.32mol / L) = 0.066 moles NaOH
As there are more moles of NaOH than moles of HCl, HCl is limiting reactant and moles of reaction are moles of limiting reactant, 0.0635 moles
Using the coffee-cup calorimeter equation we can find how many heat was released thus:
Q = C×m×ΔT
Where Q is heat released, C is specific heat of the solution (4.18J/g°C), m is mass of solution (100g because there are 100mL of solution -50.0mL of HCl and 50.0mL of NaOH- and density is 1g/mL) and ΔT is change in temperature (8.49°C)
Replacing:
Q = 4.18J/g°C×100g×8.49°C
Q = 3548.8J of heat are released in the reaction
Now, change in enthalpy, ΔH, is equal to change in heat (As is released heat ΔH < 0) per mole of reaction, that is:
ΔH = Heat / mol of reaction
ΔH = -3548.8J / 0.0635 moles of reaction
Negative because is released heat.
ΔH = -55887J / mol
ΔH =
-55.9kJ/mol is the change in enthalpy of the reaction
The heat of reaction is -54.7 kJ/mol.
The equation of the reaction is;
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
Number of moles of HCl = 50/1000 L × 1.27 M = 0.064 moles
Number of moles of NaOH = 50/1000 L × 1.32 M = 0.066 moles
The limiting reactant is HCl
Total volume of solution = 100mL
Total mass of solution = 100 g
Temperature rise = 8.49°C
Heat capacity of solution = 4.18 J/g⋅°C
Using;
H = mcdT
m = mass of solution
c = heat capacity of solution
dT = temperature rise
H = 100 g × 4.18 J/g⋅°C × 8.49°C = 3548.82 J
The heat of reaction = -ΔH/n = -(3.5kJ/0.064 moles)
= -54.7 kJ/mol
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The specific rotation of (S)-carvone (at 20°C) is +61. A chemist prepared a mixture of (R)-carvone and its enantiomer, and this mixture had an observed rotation of -55°.
A) What is the specific rotation of (R)-carvone at 20°C?
B) Calculate the % ee of this mixture.
C) What percentage of the mixture is (S)-carvone?
Answer:
a) Specific Rotation of (R)-carvone = -61°
b) The enantiomeric excess of (R)-carvone in the mixture = 90.2%
c) The percentage of (S)-carvone in the mixture = 4.9%
Explanation:
a) The specific rotation of the enantiomer of a substance is given simply as the negative of the specific rotation of that substance.
Hence, the specific rotation of (R)-carvone is simply the negative of the specific rotation of (S)-carvone.
Specific Rotation of (R)-carvone = -(61°) = -61°
b) Enantiometic excess is used to measure the optical purity of an enantiomeric mixture.
The enantiomeric excess is given mathematically as
ee% = (Observed rotation × 100)/(Specific rotation)
Hence, to calculate the enantiomeric excess of (R)-carvone,
Observed rotation of the mixture = -55°
Specific Rotation of (R)-carvone = -61°
ee% = (-55×100)/(-61) = 90.16% = 90.2%
c) An enantiomeric excess of 90.2% for (R)-carvone indicates that it's actual percentage is 90.2% more than the percentage of its enantiomeric partner, (S)-carvone, in the mixture.
Let the percentage of (R)-carvone in the mixture be x
Let the percentage of (S)-carvone in the mixture be y
x + y = 100
x - y = 90.2
2x = 190.2
x = (190.2/2) = 95.1%
y = 100 - x = 100 - 95.1 = 4.9%
Hence, the percentage of (R)-carvone in the mixture = 95.1%
The percentage of (S)-carvone in the mixture = 4.9%
Hope this Helps!!!
a) Specific Rotation of (R)-carvone = -61°
b) The enantiomeric excess of (R)-carvone in the mixture = 90.2%
c) The percentage of (S)-carvone in the mixture = 4.9%
a) Calculation of Specific Rotation:The specific rotation of the enantiomer of a substance is given simply as the negative of the specific rotation of that substance.
Hence, the specific rotation of (R)-carvone is simply the negative of the specific rotation of (S)-carvone.
Specific Rotation of (R)-carvone = -(61°) = -61°
b) Calculation for Enantiomeric excess:
The enantiomeric excess is given mathematically as
ee% = (Observed rotation × 100)/(Specific rotation)
Hence, to calculate the enantiomeric excess of (R)-carvone,
Observed rotation of the mixture = -55°
Specific Rotation of (R)-carvone = -61°
ee% = (-55×100)/(-61) = 90.16% = 90.2%
c) Calculation of percentage:
Let the percentage of (R)-carvone in the mixture be x
Let the percentage of (S)-carvone in the mixture be y
x + y = 100
x - y = 90.2
2x = 190.2
x = (190.2/2) = 95.1%
y = 100 - x = 100 - 95.1 = 4.9%
Hence, the percentage of (R)-carvone in the mixture = 95.1%
The percentage of (S)-carvone in the mixture = 4.9%
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The gas in a 250. mL piston experiences a change in pressure from 1.00 atm to 2.55 atm. What is the new volume (in mL) assuming the moles of gas and temperature are held constant?
Answer:
[tex]\large \boxed{\text{0.980 L}}[/tex]
Explanation:
The temperature and amount of gas are constant, so we can use Boyle’s Law.
[tex]p_{1}V_{1} = p_{2}V_{2}[/tex]
Data:
[tex]\begin{array}{rcrrcl}p_{1}& =& \text{1.00 atm}\qquad & V_{1} &= & \text{250. mL} \\p_{2}& =& \text{2.55 atm}\qquad & V_{2} &= & ?\\\end{array}[/tex]
Calculations:
[tex]\begin{array}{rcl}\text{1.00 atm} \times \text{250. mL} & =& \text{2.55 atm} \times V_{2}\\\text{250. mL} & = & 2.55V_{2}\\V_{2} & = &\dfrac{\text{250. mL}}{2.55}\\\\& = &\textbf{98.0 mL}\\\end{array}\\\text{The balloon's new volume is $ \large \boxed{\textbf{0.980 L}}$}[/tex]
Liquid octane reacts with gaseous oxygen gas to produce gaseous carbon dioxide and gaseous water . What is the theoretical yield of carbon dioxide formed from the reaction of of octane and of oxygen gas
Answer:
24.6g of CO₂ is theoretical yield
Explanation:
The reaction of 8.00g of octane with 38.9g of oxygen.
The reaction of octane with oxygen is:
C₈H₁₈(l) + 25/2O₂ → 9H₂O + 8CO₂
1 mole of octane reacts with 25/2 moles of oxygen to produce 8 moles of CO₂
Theoretical yield is the amount of carbon dioxide formed assuming a yield of 100%. To calculate theoretical yield, first, we need to find limiting reactant and, with the chemical reaction, we can obtain the theoretical moles of CO₂ produced and its mass to obtain theoretical yield.
Limiting reactant:
Moles octane (Molar mass: 114.23g/mol) in 8.00g:
8.00g × (1mol / 114.23g) = 0.0700 moles octane.
Moles oxygen (Molar mass: 32g/mol) in 38.9g:
38.9g × (1mol / 32g) = 1.2156 moles oxygen.
For a complete reaction of 1.2156 moles of O₂ there are necessaries:
1.2156 moles O₂ ₓ (1mol C₈H₁₈ / 25/2 moles O₂) = 0.0973 moles octane
As we have just 0.0700 moles,
octane is limiting reactant.Moles and mass of carbon dioxide:
As limiting reactant is octane, 0.0700 moles of C₈H₁₈ will produce:
0.0700mol C₈H₁₈ × (8 moles CO₂ / 1 mol C₈H₁₈) = 0.56 moles of CO₂ are theoretically produced. In mass (Molar mass CO₂ = 44.01g/mol):
0.56moles CO₂ × (44.01g / mol) =
24.6g of CO₂ is theoretical yield-Theoretical yield because we are assuming all octane is reacting. In real life, never happens like that-
g The combustion of ethylene proceeds by the following reaction: C2H4(g) + 3 O2(g) → 2 CO2(g) + 2 H2O(g) If the rate of O2 is -0.23 M/s, then what is the rate (in M/s) of disappearance of C2H4?
Answer:
Explanation:
C₂H₄(g) + 3O₂(g) → 2CO₂(g) + 2H₂O(g)
In this reaction we see that 3 moles of O₂ reacts with one mole of C₂H₄ .
Hence rate of disappearance of O₂ is 3 times faster .
- d [O₂] / dt = - 3 d [ C₂ H₄ ] / dt
Putting the given value
.23 = 3 d [ C₂ H₄ ] / dt
d [ C₂ H₄ ] / dt = .23 / 3
= .077 M / s
Hence the rate of disappearance of C₂ H₄ is .077 moles / s .