Answer:
C. The same mass of NaCl precipitate will form in Sample #2.
B. The bubbles will grow, and more may appear.
Explanation:
Solubility refers to the amount of solute that dissolves in a solvent at a particular temperature. Solubility is temperature dependent. The solubility of various substances vary with temperature as depicted in solubility curves.
If we consider the solubility curve for sodium chloride, we easily notice that the solubility of NaCl is fairly independent of temperature. The solubility variation with temperature is flat meaning that an increase in temperature has relatively little effect on the solubility of NaCl, hence, the same mass of NaCl precipitate will form in Sample #2.
For the second question, we know that in a carbonated drink, carbon dioxide is present inside the bottle under pressure. Opening the bottle means that the pressure on the liquid suddenly decreases. Less carbon dioxide is now trapped at this lower pressure, hence the extra gas in the bottle is no longer dissolved in the liquid, consequently, more bubbles form in the system .
Which of the possible compounds has a mass of 163 grams when
6.13 x 1024 molecules of the compound is put on a scale?
Answer:
CH4
Explanation:
In solving this problem, we must remember that one mole of a compound contains Avogadro's number of elementary entities. These elementary entities include atoms, molecules, ions etc. Recall that one mole of a substance is the amount of substance that contains the same number of elementary entities as 12g of carbon-12. The Avogadro's number is 6.02 × 10^23.
Hence we can now say;
If 163 g of the compound contains 6.13 ×10^24 molecules
x g will contain 6.02 × 10^23 molecules
x= 163 × 6.02 × 10^23 / 6.13 × 10^24
x= 981.26 × 10^23/ 6.13 ×10^24
x= 160.1 × 10^-1 g
x= 16.01 g
x= 16 g(approximately)
16 g is the molecular mass of methane hence x must be methane (CH4)
(4Ga + 3S2 → 2Ga2S3)
1. How many moles of Sulfur are needed to react with 12.5 moles of Gallium
Answer:
9.375
Explanation:
According to the chemical equation, for every 4 moles of gallium, 3 moles of sodium are needed to react. Set up a ratio using this relationship to solve.
4/3 = 12.5/x
4x = 37.5
x = 9.375
You need 9.375 moles of sulfur.
g A microwave oven heats by radiating food with microwave radiation, which is absorbed by the food and converted to heat. If the radiation wavelength is 12.5 cm, how many photons of this radiation would be required to heat a container with 0.250 L of water from a temperature of 20.0oC to a temperature of 99oC
Answer:
The total photons required = 5.19 × 10²⁸ photons
Explanation:
Given that:
the radiation wavelength λ= 12.5 cm = 0.125 m
Volume of the container = 0.250 L = 250 mL
The density of water = 1 g/mL
Density = mass /volume
Mass = Volume × Density
Thus; the mass of the water = 250 mL × 1 g/mL
the mass of the water = 250 g
the specific heat of water s = 4.18 J/g° C
the initial temperature [tex]T_1[/tex] = 20.0° C
the final temperature [tex]T_2[/tex] = 99° C
Change in temperature [tex]\Delta T[/tex] = (99-20)° C = 79 ° C
The heat q absorbed during the process = ms [tex]\Delta T[/tex]
The heat q absorbed during the process = 250 g × 4.18 J/g° C × 79° C
The heat q absorbed during the process = 82555 J
The energy of a photon can be represented by the equation :
= hc/λ
where;
h = planck's constant = [tex]6.626 \times 10^{-34} \ J.s[/tex]
c = velocity of light = [tex]3.0 \times 10^8 \ m/s[/tex]
= [tex]\dfrac{6.626 \times 10^{-34} \times 3.0 \times 10^8}{0.125}[/tex]
= [tex]1.59024 \times 10^{-24}[/tex] J
The total photons required = Total heat energy/ Energy of a photon
The total photons required = [tex]\dfrac{82555 J}{1.59024 \times 10^{-24}J}[/tex]
The total photons required = 5.19 × 10²⁸ photons
The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 178C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.
A) The specific humidity of the air with the given parameters is;
w1 = 0.00967
B) The relative humidity of the air with the given parameters is;
Φ1 = 0.459
C) The enthalpy of the air in KJ/kg dry air with the given parameters is;
h1 = 49.75 KJ/Kg
Correct question is;
The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 17 °C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.
We are given;
Atmospheric Pressure;P = 95 KPa
Dry temperature;T1 = 25 °C
Wet temperature;T2 = 17°C
A) From table A-4 attached and at temperature of 17°C and by interpolation, we have a saturation pressure of P_g2 = 1.938 kpa
First of all, we will calculate the specific humidity from the given pressure and saturation pressure with the formula;
w2 = (0.622 × P_g2)/(P - P_g2)
w2 = (0.622 × 1.938)/(95 - 1.938)
w2 = 0.013
Now, let's calculate specific humidity with the enthalpies at 17 °C and by interpolation. We have specific enthalpies from table A-4 as;
h_fg2 = 2460 KJ/Kg
h_g1 = 2546.5 KJ/Kg
h_f2 = 71.36 KJ/Kg
The formula for the specific humidity under these conditions is;
w1 = (c_p(T2 - T1) + w2•h_fg2)/(h_g1 - h_f2)
c_p of air has a value of 1.005 KJ/Kg.°C
Thus;
w1 = (1.005(17 - 25) + 0.013*2460)/(2546.5 - 71.36)
w1 = 0.00967
B) The relative humidity is determined from the equation;
Φ1 = (w1*p)/(0.622 + w1)p_g1
From table A-4 attached and at temperature of 25 °C, we have a saturation pressure of P_g1 = 3.1698 KPa
Φ1 = (0.00967*95)/(0.622 + 0.00967)3.1698
Φ1 = 0.459
C) For the enthalpy of air, h1 we will use the formula;
h1 = (c_p × T1) + (w1 × h_g1)
h1 = (1.005 × 25) + (0.00967 × 2546.5)
h1 = 49.75 KJ/Kg
Read more at; https://brainly.com/question/13826648
A sample containing 1.20 moles of Ne gas has an initial volume of 7.50 L. What is the final volume of the gas, in liters, when each of the following changes occur in the quantity of the gas at constant pressure and temperature?
1) a leak allows one half of the Ne atoms to escape
2) a sample of 3.10 moles of Ne is added to the 1.20 moles of Ne gas in the container
3) a sample of 35.0 g of Ne is added to the 1.20 moles of Ne gas in the container.
Answer:
1 = 3.75L
2 = 26.91L
3 = 18.37L
Explanation:
Hello,
The question above can be solved when we know Avogadro's law which states that the volume of a fixed mass of gas is directly proportional the number of moles present provided temperature and pressure are kept constant.
Mathematically,
N = kV k = n/v
N1/V1 = N2/V2 = N3/V3 =......=Nn/Vn
N1 = 1.20 moles
V1 = 7.50L
1) if half of the Ne atoms escaped what would be the final volume.
1 mole of Ne = 6.022×10²³ atoms
½(1.20) moles of Ne = ?
0.6 moles of Ne = ?
1 mole = 6.022×10²³ atom
1.2 moles = ?
x = 1.2 × 6.022×10²³ atoms
x = 7.23×10²³atoms
If ½ of 7.23×10²³ atoms escaped, how many would be left
½ × 7.23×10²³ atoms = 3.61×10²³atoms
Now we have to find the number of moles and then use our equation.
1 mole = 6.022×10²³ atoms
y mole = 3.61×10²³ atom
y = 0.6 mole
N2 = 0.6 mole
N1 / V1 = N2 / V2
Make V2 the subject of formula,
V2 = (N2 × V1) / N1
V2 = (0.6 × 7.50) / 1.20
V2 = 3.75L
The volume after half of the Ne atoms escaped is 3.75L
2)
When a sample of 3.10 mole is added to 1.20 moles present
N1 = 1.20
V1 = 7.51
N2 = (1.20 + 3.10) = 4.30L
V2 = ?
N1 / V1 = N2 / V2
V2 = (N2 × V1) / N1
V2 = (4.30 × 7.51) / 1.20
V2 = 26.91L
The volume of Ne gas if 3.10 moles is added to it is 26.91L
3)
A sample of 35g is added to the 1.20 mole Ne in the container.
We need to convert the mass (35g) to moles. This can be done using mass-molarmass relationships
Number of moles = mass / molar mass
Molar mass of Ne = 20.17g/mol
Number of moles = 35 / 20.17
Number of moles = 1.735 moles
N2 = 1.20 moles + 1.735 moles
N2 = 2.935 moles
N1 / V1 = N2 / V2
V2 = (N2 × V1) / N1
V2 = (2.935 × 7.51) / 1.20
V2 = 18.37L
On addition of 35g of Ne gas to the container, the volume is increased to 18.37L
Which of the following functional groups is not present in the HIV protease inhibitor drug below called Saquinavir?
A) alcohol
B) amide
C) aromatic ring
D) amine
E) ketone N. ○ ト Saquinavir Structure
Answer:
alcohol
Explanation:
Since in its chemical structure it presents an amide, amine and aromatic ring group.
What this drug does is inhibit the protease of the HIV retrovirus, the protease is an enzyme that catalyzes proteins.
pls answer these questions for brainliest
katya is investigating displacement reactions . She heats the pairs of substances in this list
iron and aluminium oxide
iron and copper oxide
copper and magnesium oxide
iron and lead oxide
a)write down the letters os 2 pairs of substances that react . Explain your choices
b) choose one pair of substances that react . write a word equation for the reaction
Calculate the work (kJ) done during a reaction in which the internal volume expands from 28 L to 51 L against an outside pressure of 4.9 atm.
Answer:
W= -11KJ
Explanation:
Given:
volume expands from 28 L to 51 L
pressure =4.9 atm.
We will need to Convert the pressure to Pascal SI
But 1 atm = 101,325 Pa.
Then,
Pressure= (4.9*101323)/1atm = 5*10^5 pa
Then we need to Convert the volumes to cubic meters
But we know that1 m³ = 1,000 L.
V1= 28L * 1m^3/1000L = 0.028m^3
V2=51L × 1m^3 /1000L =0.051m^3
The work done during the expansion of a gas can be calculated as
W= -P(V2-V1)
W= - 5*10^5(0.051m^3 - 0.028m^3)
W= -1.1× 10^4J
Then we can Convert the work to kiloJoule
But1 kJ = 1,000 J.
W= -1.1× 10^4J× 1kj/1000J
= -11KJ
For a given sample of C3H8(g), the enthalpy change during the reaction is -784kJ. How many grams of CO2 are produced? Group of answer choices g
Answer:
[tex]m_{CO_2}=46.6gCO_2[/tex]
Explanation:
Hello,
In this case, considering the combustion of propane:
[tex]C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)\ \ \ \Delta _CH=-2220.0 kJ/mol[/tex]
We can compute the burnt moles of propane as shown below:
[tex]n=\frac{-784kJ}{-2220.0 kJ/mol} =0.353molC_3H_8[/tex]
Then, by noticing propane and carbon dioxide are in a 1:3 molar ratio, we can compute the grams carbon dioxide by using the shown below stoichiometric procedure:
[tex]m_{CO_2}=0.353molC_3H_8*\frac{3molCO_2}{1molC_3H_8} *\frac{44gCO_2}{1molCO_2} \\\\m_{CO_2}=46.6gCO_2[/tex]
Best regards.
Which of the following pairings usually forms molecular compounds?
Select the correct answer below:
metal, nonmetal
nonmetal, nonmetal
metal, metal
none of the above
A nonmetal and a nonmetal will make molecular compounds like H2O and CO2
Grams of cl in 38g of cf3cl
Answer:
114 grams
Explanation:
3chlorines per compound*38grams=114
How many moles of CO are produced when 1.2 moles C reacts? Equation: 5C(s)+2SO2(g)→CS2(l)+4CO(g)
Answer:
0.96 mol CO
Explanation:
We simply just use the reaction to help us find this:
[tex]1.2 mol C(\frac{4 mol CO}{5 mol C} )[/tex]
Multiply it out and we get 0.96 as our answer.
which vitamin is more soluble in water ? explain
Answer:
Vitamin C and B complex is the water soluble.but in question option is A abd C so, among them vitamin C is the water soluble vitamin.
Explanation:
Because it is easily soluble in water and when there is more amount of asorbic acid it has to be mixed in urine and are released out from body.
hope it helps..
Strontium crystallizes in a face-centered cubic unit cell having an edge length of 77.43 pm. What is the atomic radius of strontium (in picometers) based on this structure
Answer:
Atomic radius of Strontium is 27.38pm
Explanation:
In a face-centered cubic structure, the edge, a, could be obtained using pythagoras theorem knowing the hypotenuse of the unit cell, b, is equal to 4r:
a² + a² = b² = (4r)²
2a² = 16r²
a = √8 r
As edge length of Strontium is 77.43pm:
77.43pm / √8 = r
27.38pm = r
Atomic radius of Strontium is 27.38pm2. A student has a centrifuge tube containing 14.0 g of t-butanol and is asked to make a 1.2 m solution of ethanol/t-butanol. How much ethanol would the student need to add in mL and in g? Show your calculations. Show your calculations. (6 pts)
Answer:
0.774g of ethanol
0.970mL of ethanol
Explanation:
Molality is an unit of concentration defined as the ratio between moles of solute and kg of solvent.
In the problem, you need to prepare a 1.2m solution of ethanol (Solute) in t-butanol (solvent).
14.0g of butanol are 0.014kg and as you want to prepare the 1.2m solution, you need to add:
0.014kg × (1.2moles / kg) = 0.0168 moles of solute = Moles of ethanol
To convert moles of ethanol to mass you require molar mass (Molar mass ethanol, C₂H₅OH = 46.07g/mol). Thus, mass of 0.0168 moles are:
0.0168moles Ethanol ₓ (46.07g / mol) =
0.774g of ethanolAnd to convert mass in g to mL you require density of the substance (Density of ethanol = 0.798g/mL):
0.774g ₓ (1mL / 0.798g) =
0.970mL of ehtanolWhen aqueous solutions of NH4OH(aq) and CuCl2(aq) are mixed, the products are NH4Cl(aq) and Cu(OH)2(s). What is the net ionic equation for this reaction
Answer:
2OH^-(aq) + Cu^2+(aq) -----> Cu(OH)2(s)
Explanation:
The net ionic equation usually shows the main ionic reaction that goes in the system. The other ions that do not participate in this net ionic equation are called spectator ions. Spectator ions do not participate in the main reaction occurring in the system.
The net ionic equation quite often result in the formation of a solid precipitate in the system such as Cu(OH)2.
The net ionic equation for this reaction is;
2OH^-(aq) + Cu^2+(aq) -----> Cu(OH)2(s)
an extra strength antacid tablet contains 750 mg of active ingredient, caco3. if it takes 22.25 ml of hcl to neutralize the tablet, how strong is the acid
Answer:
The HCl is very strong since its pH is equal to 0.17.
Explanation:
The reaction between CaCO₃ and HCl is:
CaCO₃(s) + 2HCl(aq) ⇄ CaCl₂(aq) + CO₂(g) + H₂O(l) (1)
The number of moles of CaCO₃ is:
[tex] n_{CaCO_{3}} = \frac{m}{M} [/tex]
Where:
m: is the mass = 0.750 g
M: is the molar mass = 100.0869 g/mol
[tex] n_{CaCO_{3}} = \frac{0.750 g}{100.0869 g/mol} = 7.49 \cdot 10^{-3} moles [/tex]
From the reaction (1) we have that 1 mol of CaCO₃ reacts with 2 moles of HCl, so the number of moles of HCl is:
[tex] n_{HCl} = 2*7.49 \cdot 10^{-3} moles = 0.015 moles [/tex]
Now, with the number of moles of HCl we can find its concentration:
[tex] C = \frac{n}{V} = \frac{0.015 moles}{22.25 \cdot 10^{-3} L} = 0.67 M [/tex]
Finally, the pH of the acid is:
[tex] pH = -log([H^{+}]) = -log(0.67) = 0.17 [/tex]
The pH obtained is very low, so the HCl is very strong.
Therefore, the HCl is very strong since its pH is equal to 0.17.
I hope it helps you!
Which one of the following would have the largest dispersion forces?
A) CH3CH2SH
B) CH3NH2
C) CH4
D) CH3CH3
Answer:
A) CH3CH2SH
Explanation:
Dispersion forces are weak attractions found between non-polar and polar molecules. The attractions here can be attributed to the fact that a non-polar molecule sometimes become polar because the constant motion of its electrons may lead to an uneven charge distribution at an instant. If this happens, the molecule has a temporary dipole. This dipole can induce the neighbouring molecules to be distorted and form dipoles as well. The attractions between these dipoles constitute the Dispersion Forces.
Therefore; the greater the molar mass of a compound or molecule, the higher the Dispersion Force. This implies that the compound or molecule with the highest molar mass have the largest dispersion forces.
Now; for option (A)
CH3CH2SH
The molar mass is :
= (12 + (1 × 3 ) +12 + (1 ×2) + 32+1)
= (12 + 3+ 12 + 2 + 32 + 1)
= 62 g/mol
For option (B)
CH3NH2
The molar mass is:
= (12 + (1 × 3 ) +14 + (1 × 2)
= (12 + 3 + 14 + 2)
= 31 g/mol
For option (C)
CH4
The molar mass is :
= 12 + (1 × 4)
= 12 + 4
= 16 g/mol
For option (D)
CH3CH3
The molar mass is :
= 12 + ( 1 × 3 ) + 12 + ( 1 × 3)
= 12 + 3 + 12 + 3
= 30 g/mol
Thus ; option (A) has the highest molar mass, as such the largest dispersion force is A) CH3CH2SH
Suppose that you add 28.8 g of an unknown molecular compound to 0.250 kg of benzene, which has a K f Kf of 5.12 oC/m. With the added solute, you find that there is a freezing point depression of 3.06 oC compared to pure benzene. What is the molar mass of the unknown compound
Answer:
THE MOLAR MASS OF THE UNKNOWN COMPOUND IS 242.02 g/mol.
Explanation:
First:
Calculate the change in freezing point:
Freezing point of pure benzene = 5.5°C
Change in temperature = 5.5 - 3.06 = 2.44 °C
Second:
Using the formula:
Δt = i Kf m
Let's assume i = 1
Kf = 5.12 °C/m
M = x / 0.250 kg of benzene
Then we can calculate x which is the molarity
Re-arranging the formula, we have:
m = Δt / i Kf
x / 0.250 = 2.44 / 1 * 5.12
x = 2.44 * 0.250 / 5.12
x = 0.61 / 5.12
x = 0.119 M
Since it is well known that molarity is the mass of a substance divided by its molar mass. We can then calculate the molar mass.
Molar mass = Mass / molarity
Molar mass = 28.8 g / 0.119 M
Molar mass =242.02 g/mol
Hence, the molar mass of the unknown molecular compound is 242.02 g/mol.
The Ka1 value for oxalic acid is 5.9 x10-2 , and the Ka2 value is 4.6 x 10-5 . What are the values of Kb1 and Kb2 of the oxalate ion
Answer:
2.17x10⁻¹⁰ = Kb1
1.69x10⁻¹³ = Kb2
Explanation:
Oxalic acid, C₂O₄H₂, has two intercambiable protons, its equilibriums are:
C₂O₄H₂ ⇄ C₂O₄H⁻ + H⁺ Ka1 = 5.9x10⁻²
C₂O₄H⁻ ⇄ C₂O₄²⁻ + H⁺ Ka2 = 4.6x10⁻⁵
Oxalate ion, C₂O₄²⁻, has as equilibriums:
C₂O₄²⁻ + H₂O ⇄ C₂O₄H⁻ + OH⁻ Kb1
C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2
Also, you can know: KaₓKb = Kw
Where Kw is 1x10⁻¹⁴
Thus:
Kw = Kb2ₓKa1
1x10⁻¹⁴ =Kb2ₓ4.6x10⁻⁵
2.17x10⁻¹⁰ = Kb1And:
Kw = Kb1ₓKa2
1x10⁻¹⁴ =Kb1ₓ5.9x10⁻²
1.69x10⁻¹³ = Kb1
That is because the inverse reaction of, for example, Ka1:
C₂O₄H⁻ + H⁺ ⇄ C₂O₄H₂ K = 1 / Ka1
+ H₂O ⇄ H⁺ + OH⁻ K = Kw = 1x10⁻¹⁴
=
C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2 = Kw × 1/Ka1
on the basis of Le chatelier's Principle explain why the addition of Solid NH4Cl to a saturated solution of Mg(OH)2 in water causes more of the Mg(OH)2 to dissolv
Explanation:
Le Chetelier's principle states that in an equilibrium system, if a constraint (such as a change in pressure, temperature, or concentration of a reactant) is applied to the system, the equilibrium will shift so as to tend to annul the effect of the constraint. For the dissolution of Solid Magnesium oxide Mg(OH)2 in water, normally, only a small amount of the solid is dissolved to form magnesium ions Mg^2+ and hydroxide ions 2OH-. In a saturated solution of magnesium oxide in water, any action that removes the hydroxide ions formed will cause the reaction to shift to the product side on the right to favor the production of more hydroxide ion, which means more of the magnesium oxide will be dissolved.
Addition of Ammonium chloride NH4Cl neutralizes the hydroxide ions by acting as an acid, to form ammonia NH3 and water H20. This is because the Ammonium chloride dissolves to form ammonium NH4 and chlorine Cl^- ions in the solution, allowing the ammonium to react with the hydroxide ions. The reactions are shown below.
Mg(OH)2 ⇄ Mg^2+ 2OH^- ....... initial magnesium oxide dissolution
NH4Cl ⇒ NH4 + Cl ......... dissolution of ammonium chloride
NH4 + OH^- ⇒ NH3 + H2O ....... the consumption of the hydroxide ion by the ammonium to form ammonia and water, leading to more of the magnesium oxide dissolving to form more hydroxide ions.
What mass of benzene is cooled from 83.8 °C to 77.1 °C when 167 J of energy is transferred out of the system? (The specific heat of benzene is 1.740 J/g °C).
Answer:
14.32g
Explanation:
Initial temperature = 83.8°C
Final temperature = 77.1°C
Temperature change, ΔT = 83.8°C - 77.1°C = 6.7
Heat, H = 167J
Specific heat, c = 1.740J/g °C
m = ?
All these parameters are related with the equation below;
H = mcΔT
m = H / cΔT
m = 167 / (1.740 * 6.7)
m = 167 / 11.658 = 14.32g
How many water molecules are in a block of ice containing 0.500 mol of water (H2O)?
Answer:
3.01 × 10²³ molecules
Explanation:
Step 1: Given data
Moles of water (n): 0.500 mol
Step 2: Calculate the molecules of water present in 0.500 moles of water
In order to perform this calculation, we will use the Avogadro's number: in 1 mole of water there are 6.02 × 10²³ molecules of water.
0.500 mol × (6.02 × 10²³ molecules/1 mol) = 3.01 × 10²³ molecules
the reation between sulfur dioxide and oxygen is a dynamic equilibrium. what happens when the pressure of the system is
increased ?
Answer:
In the above reaction, sulfur dioxide and oxygen react together to form sulfur trioxide. This means that an increase in pressure would move the equilibrium to the right and result in more sulfur trioxide being formed. Pressure can only affect the position of equilibrium if there is a change in the total gas volume.
Phosphorus pentachloride decomposes to phosphorus trichloride at high temperatures according to the equation:
PCl5(g) = PCl3(g) + Cl2(gu)
at 250 Co , 0.125M PCl5 is added to the flask , if Kc=1.80, what are the equilibrium concentrations of each gas?
A) [PCl5]=0.0625M,[PCl3]=0.0335M,and [Cl2]=0.335M
B) [PCl5]=1.80M,[PCl3]=1.80M,and [Cl2]=1.80M
C) [PCl5]=0 M,[PCl3]=1.34M,and [Cl2]=1.34M
D) [PCl5]=0.00765M,[PCl3]=0.117M,and [Cl2]=0.0.117M
E) [PCl5]=3.96M,[PCl3]=3.83M,and [Cl2]=3.83M
Answer:
D) [PCl5]=0.00765M,[PCl3]=0.117M,and [Cl2]=0.0.117M
Explanation:
Based on the reaction:
PCl₅(g) ⇄ PCl₃(g) + Cl₂(g)
And knowing:
Kc = [PCl₃] [Cl₂] / [PCl₅] = 1.80
When you add PCl₅ into a flask, this gas will react producing PCl₃ and Cl₂ until [PCl₃] [Cl₂] / [PCl₅] = 1.80
This could be written as:
[PCl₃] = X
[Cl₂] = X
[PCl₅] = 0.125M - X
Where X represents the moles of PCl₅ that react, reaction coordinate.
Replacing in Kc expression:
[PCl₃] [Cl₂] / [PCl₅] = 1.80
[X [X] / [0.125 - X] = 1.80
X² = 0.225 - 1.80X
0 = -X² -1.80X + 0.225
Solving for X:
X = -1.9M → False solution, there is no negative concentrations
X = 0.11735M → Right solution.
Replacing, concentrations in equilibrium are:
[PCl₃] = X
[Cl₂] = X
[PCl₅] = 0.125M - X
[PCl₃] = 0.117M
[Cl₂] = 0.117M
[PCl₅] = 0.00765M
And right option is:
D) [PCl5]=0.00765M,[PCl3]=0.117M,and [Cl2]=0.0.117MWhich one of the following substances, when dissolved in water at equal molar concentrations, will give the solution with the lowest electrical conductivity
a. CaC12
b. HNO3
c. NH3
d. C6H12O6 (glucose)
e. CO2
The substance which gives more ions in ionization will be more conductive and those giving less ions will be less conducting. Here, glucose only give no ion in water thus, it has the lower conductivity.
What is ionization?Ionization is the process of dissociation of compounds into its constituent ions. For example, HCl when dissolved in water will give H+ and Cl- ions. Similarly HNO₃ gives H+ and NO₃- ions in ionization.
Water can easily dissolves the ionic compounds by forming hydrogen bonds with them and thus easily ionises them The ions formed are mobile and conduct electricity. The more the number of ions the higher the electrical conductivity.
CaCl₂ gives Ca²⁺ and two Cl- ions and NH₃ gives NH₄⁺ ions and CO₂ gives H+ ions by the formation of carbonic acid. Wheres, glucose does not give its ions and thus has lower conductivity for the solution.
To find more on conductivity, refer here:
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A client with a long history of cigarette smoking and poorly controlled hypertension is
experiencing psychomotor deficits due to hemorrhagic brain damage. Which diagnosis is likely
for the onset of progressive dementia?
Answer:
It may be a hemorrhagic stroke because of the patient's history.
Explanation:
Uncontrolled hypertension could generate a hemorrhagic stroke within the brain generating the sign of progressive dementia, this is due to the vessel breaking due to the excess pressure of the internal light, it breaks and releases or extravases all the bloody contents to the brain
The difficulty of this is that the brain is the one that yields to a force in relation to the skull, that is why it is compressible against hemorrhage generating these signs as progressive dementia and could even be death or vegetative state
How many hours does it take to form 15.0 L of O₂ measured at 750 torr and 30°C from water by passing 3.55 A of current through an electrolytic cell?
Answer:
The correct answer is 17.845 hours.
Explanation:
To solve the question, that is, to determine the hours required there is a need to combine the Faraday's law of electrolysis with the Ideal gas law.
Based on Faraday's law, m = Mit/nF
Here m is the mass in grams, M is the molecular mass, i is the current in amperes, t is time, n is the number of moles of electron per mole of oxygen formed and F is the Faraday's constant (the value of F is 96487 coulombs/mole).
From the above mentioned equation,
t = mnF/Mi ------(i)
Now based on ideal gas law's, PV = nRT or PV = m/M RT, here n = mass/molecular mass.
So, from the above gas law's equation, m = PVM/RT
Now putting the values of m in the equation (i) we get,
t = PVMnF/MiRT = PVnF/iRT
Based on the given information, the value of P is 750 torr or 750/760 atm = 0.98 atm, the value of v is 15.0 L, T is 30 degree C or 273 + 30 K = 303 K, i is 3.55 Amperes, and the value of R is 0.0821 atm L/mol K.
1 mole of oxygen gives 2 moles of electrons, therefore, 2 moles of oxygen will give 4 moles of electrons.
Now putting the values we get,
t = PVnF/iRT
= 0.98 atm × 15.0 L × 4 moles of electron × 96487 coulombs per mole / 3.55 coulomb per sec × 0.0821 atm L per mole-K × 303 K
= 64243.81 secs or 64243.81/3600 hr
= 17.845 hours
Calculate the energy of a photon of electromagnetic radiation at each of the following wavelengths.
a. 632.8 nm (wavelength of red lightfrom helium-neon laser)
b. 503 nm (wavelength of maximumsolar radiation)
c. 0.0520 nm (a wavelength contained inmedical X-rays)
Answer:
A)566×10^-16J
B)711.99×10^-16J
C)688.69×10^-12J
Explanation:
A)
But we know that
1 nm = 10^-9 m
Then we can Convert from nanometer to metre which is SI unit
632.8 nm = 632.8×10^-9 m = 6.328×10^-7 m
The speed of light is c = 2.998×10^8 m/s
λ = 6.328×10^-7 m
But the frequency can be calculated as;
ƒ = c / λ
ƒ = (2.998×10^8 m/s) / (6.328×10^-7 m)
Then
ƒ = 4.738×10^14 s-1
To calculate Energy we use
Energy= hf
Where h is plank constant= 6.626× 10^-34
Energy= 6.626× 10^-34 × 4.738×10^14=566×10^-16J
B)
But we know that
1 nm = 10^-9 m
Then we can Convert from nanometer to metre which is SI unit
Then 503 nm = 503×10^-9 m = 5.03×10^-7 m
c = 2.998×10^8 m/s
λ = 5.03×10^-7 m
But the frequency can be calculated as;
ƒ = c / λ
ƒ = (2.998×10^8 m/s) / (5.03×10^-7 m)
ƒ = 5.960×10^14 s-1
Energy= 6.626× 10^-34 × 5.960×10^14 s-1= 711.99×10^-16J
C)
1 nm = 10^-9 m
0.0520 nm = 0.0520×10^-9 m = 5.20×10^-11 m
Where the speed of light is
c = 2.998×10^8 m/s
λ = 5.20×10^-11 m
But the frequency can be calculated as;
ƒ = c / λ
ƒ = (2.998×10^8 m/s) / (5.20×10^-11 m)
ƒ = 5.765×10^18 s-1
Energy= 6.626× 10^-34 × 5.765×10^18 s-1= 688.69×10^-12J
In Sir Isaac Newton's time in the early 1700s, what was the general consensus among scientists on the properties of light?
Answer:
Light is composed of particles and travels in a straight line.
Explanation:
The general consensus among scientists in Sir Isaac Newton's time in the early 1700s was that light was composed of a steady stream of particles, since it was observed that light traveled in a straight line and was able to pass through a vacuum. They argued along the lines of Sir Isaac Newton that since sound travels in waves and cannot travel though a vacuum, light must consist of something other than waves, such as particles.
Also, on reflection of light from rough surfaces, the particle theory suggests that if the surface is very rough, the particles bounce away at different angles from the surface, scattering the light as is confirmed by experimental observation.
In his 1704 book Opticks, Sir Isaac Newton stated that "Light is never known to follow crooked passages nor to bend into the shadow". This idea lent support to the particle theory, which proposes that light particles must always travel in straight lines. If the particles encounter the edge of a barrier, then they will cast a shadow because the particles not blocked by the barrier continue on in a straight line and cannot spread out behind the edge. This was observed in eclipses as well as formation of shadow of objects.
Answer:
Light is composed of particles and travels in a straight line.
Explanation:
PF The majority of scientists in the early 1700s agreed that light must be particle-like, since it was apparent that light traveled in a straight line and was able to pass through a vacuum. Their logic was that since sound travels in waves and can't travel though a vacuum, light must consist of something other than waves, such as particles.