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Unformatted text preview: Honour Chemistry Practice Test: Unit 2: Matter as Solutions and Gases
1 atm = 760 mm Hg = 760 torr = 101.325 kPa
STP = 22.4 L/mol @ 0.00°C & 101.325 kPa (1 atm)
R = 0.0821 L • atm
K • mol or 8.314 L • kPa
K • mol P1V1 P2V2
n1T1 n2T2 PV = nRT % by Mass = C= nsolute
Vsolution m solute
m solution Molality = r1
r2 C = kP i= n ions
n solute m
V n= M2
M C1V1 = C2V2 χ1 = n1
PTotal nTotal = n1 + n2 + n3 + … % (v/v) =
m solvent in kg SATP = 24.8 L/mol @ 25.0°C & 100. kPa
D= PTotal = P1 + P2 + P3 + … TK = TC + 273.15 Vsolute
ppm = % (m/v) = m solute (mg)
V solution (L) ΔTb = iKb × Molalitysolute m solute in g
Vsolution in mL
ppb = ΔTf = iKf × Molalitysolute Part A: Multiple Choice
1. m solute (μg)
V solution (L) (1 point each) Which of these compounds is a strong electrolyte?
C. H2SO4 D. C6H12O6 E. CH3COOH 2. Based on the solubility rules, which of these processes will occur if solutions of CuSO4 (aq) and BaCl2 (aq)
A. CuCl2 will precipitate; Ba2+ and SO42− are spectator ions.
B. CuSO4 will precipitate; Ba2+ and Cl− are spectator ions.
C. BaSO4 will precipitate; Cu2+ and Cl− are spectator ions.
D. BaCl2 will precipitate; Cu2+ and SO42− are spectator ions.
E. No precipitate will form. 3. Which of these choices is the correct net ionic equation for the reaction that occurs when solutions of
Pb(NO3)2 and NH4Cl are mixed?
E. 4. A 4.691 g sample of MgCl2 is dissolved in enough water to give 750. mL of solution. What is the
magnesium ion concentration in this solution?
D. 5. Pb(NO3)2 (aq) + 2 NH4Cl (aq) → NH4NO3 (aq) + PbCl2 (s)
Pb2+(aq) + 2Cl− (aq) → PbCl2 (s)
Pb2+(aq) + 2 NO3−(aq) + 2 NH4+(aq) + 2 Cl−(aq) → 2 NH4+(aq) + 2 NO3−(aq) + PbCl2 (s)
NH4+(aq) + NO3−(aq) → 2 NH4NO3 (s)
No reaction occurs when the solutions are mixed. 3.70 × 10−2 M
4.93 × 10−2 M B. 1.05 × 10−2 M
E. 0.131 M C. 6.57 × 10−2 M Lithium metal dissolves in water to yield hydrogen gas and aqueous lithium hydroxide. What is the
final concentration of hydroxide ions when 5.500 g of lithium metal is dropped into 750. mL of water?
A. 1.06 M
B. 0.528 M
C. 2.11 M
D. 0.792 M
E. 0.943 M
Page 1 of 4. 6. Which of the following gas molecules have the highest average kinetic energy at 25°C?
E. All the gases have the same average kinetic energy. 7. If 30.0 L of oxygen are cooled from 200ºC to 1°C at constant pressure, what is the new volume of
oxygen? A. 0.150 L B. 17.4 L C. 23.0 L D. 51.8 L E. 6.00 × 103 L 8. If the pressure of a gas sample is quadrupled and the absolute temperature is doubled, by what factor
does the volume of the sample change?
E. ⅛ 9. Two moles of chlorine gas at 20.0°C are heated to 350°C while the volume is kept constant. The
density of the gas
C. remains the same.
D. Not enough information is given to correctly answer the question. 10. A mixture of three gases has a total pressure of 1,380 mmHg at 298 K. The mixture is analyzed and is
found to contain 1.27 mol CO2, 3.04 mol CO, and 1.50 mol Ar. What is the partial pressure of Ar?
A. 0.258 atm
B. 301 mmHg
C. 356 mmHg
D. 5,345 mmHg
E. 8,020 mmHg
11. What volume of oxygen gas at 320 K and 680 torr will react completely with 2.50 L of NO gas at the
same temperature and pressure?
2 NO (g) + O2 (g) → 2 NO2 (g)
A. 1.25 L
B. 2.50 L
C. 3.00 L
D. 1.00 L
E. 5.00 L
12. Deviations from the ideal gas law are greater at
A. low temperatures and low pressures.
C. high temperatures and high pressures. B.
D. low temperatures and high pressures.
high temperatures and low pressures. 13. Determine the pressure of the gas trapped in the apparatus
shown below when the atmospheric pressure is 695 mmHg.
A. 45 mmHg
B. 650 mmHg
C. 695 mmHg
D. 740 mmHg
E. 760 mmHg
14. 1.000 atm of oxygen gas, placed in a container having a pinhole opening in its side, leaks from the
container 2.14 times faster than does 1.000 atm of an unknown gas placed in this same apparatus.
Which of the following species could be the unknown gas?
15. Which of the following would be expected to have the lowest vapour pressure at room temperature?
C. ethanol, bp = 78°C
water, bp = 100°C B.
D. methanol, bp = 65°C
acetone, bp = 56°C 16. Which property of water allows a razor blade to float on it without sinking?
B. surface tension
D. specific heat
Page 2 of 4. E. triple point 17. A liquid boils when its
A. vapour pressure is exactly 1 atmosphere.
B. vapour pressure is equal to, or greater than, the external pressure pushing on it.
C. temperature is equal to 273 K (standard temperature).
D. temperature is greater than room temperature.
18. Use the graph of vapour pressure to determine the
normal boiling point of trichloromethane, CHCl3.
70°C 19. What is the molarity of a solution that is 26.0% by mass phosphoric acid (H3PO4) and that has a density
of 1.155 g/mL?
A. 2.30 × 10-3 M B. 0.30 M C. 2.30 M D. 3.06 M E. 300 M 20. Calculate the percent by mass of potassium nitrate in a solution made from 45.0 g KNO3 and 295 mL of
water. The density of water is 0.997 g/mL.
A. 1.51 %
B. 7.57 %
C. 13.3 %
D. 15.2 %
E. none of these
21. Calculate the molality of a solution containing 14.3 g of NaCl in 42.2 g of water.
A. 2.45 × 10−4 m B. 5.80 × 10−4 m C. 2.45 × 10−1 m D. 103 m E. 5.80 m 22. Which of the following aqueous solutions has the highest boiling point? (Kb for water is 0.52°C/m)
A. 0.2 m KCl
B. 0.2 m Na2SO4
C. 0.2 m Ca(NO3)2
D. 0.2 m KCl and 0.2 m Na2SO4
E. 0.2 m Na2SO4 and 0.2 m Ca(NO3)2
23. Calculate the freezing point of a solution made from 21.0 g NaCl and 100. g of H2O. (Kf H2O = 1.86°C/m)
A. 3.59°C B. 6.68°C C. −13.4°C D. −6.68°C Part B: Numerical Response E. −3.59°C
(1 point each) 1. A chemistry student needs 500. mL of 0.350 M of K2CO3 solution. The mass of solute required for this
solution is ______________ g
2. It is found that it takes 32.0 mL of a 0.400 mol/L barium hydroxide solution to completely titrate 10.0 mL
unknown concentration of hydrochloric acid. Given the unbalanced chemical equation below, the
concentration of the acid is __________ mol/L
___ HCl (aq) + ___ Ba(OH)2 (aq) → ___ HOH (l) + ___ BaCl2 (aq) 3. A 0.500 mol of gas at 25.0°C has a volume of 300. mL. It is in a cylinder with an expandable in a piston.
Suppose the pressure of the gas is kept constant while a worker injects another 0.300 mol of the same gas
and raise the temperature to 100.°C. The new volume of the gas in this cylinder is ___________ mL.
4. A 353 mL soda bottle consists of 4.83 mol/L of CO2. At 25°C, the partial pressure of CO2 in air is
29.18 torr at a concentration 0.0681 mol/L. The pressure of CO2 in the soda bottle is ___________ kPa.
5. A hydrogen peroxide solution is made from adding 56.0 mL of pure H2O2 (l) into 422 mL of water.
It’s % (v/v) solution is ______________ %.
Page 3 of 4. 6. 35.0 mL of 0.255 M nitric acid is added to 45.0 mL of 0.328 M Mg(NO3)2. The concentration of nitrate
ion in the final solution is _______________ M.
7. An unknown gas has a density 4.25 g/L at STP, its molar mass is _____________ g/mol.
Part C: Extended Response
1. Water vapour is produced from the chemical reaction between hydrogen gas and oxygen gas. Suppose
5.00 L of H2 (g) at STP is reacted with 8.50 L of O2 (g) at 15.0°C and 793.0 mmHg. Determine the mass of
water vapour produced at SATP.
2. Determine the mass of glucose needed to raise the boiling point of 3.00 L water to 102.0°C assuming
water has a density of 1.00 g/mL. (Kb of water = 0.510°C • kg/mol)
3. A substance that has a triple point at −15°C and 0.30 atm, melts at −10.0°C at 1.0 atm, and has a normal
boiling point of 90°C.
a. Sketch the phase diagram for this substance.
b. Based on the phase diagram in part a., below what pressure and temperature would the substance
undergo sublimation? Explain your reasoning. Part A: Multiple Choice
21. E 2. C
22. E 3. B
23. C 4. C
14. B 5. A
15. C 6. E
16. B 7. B
17. B 8. C
18. D 9. C
19. D 10. C
20. C Part B: Numerical Response
1. ___24.2____ 2. ___2.56____ 3. ____601_____ 5. ___11.7____ 6. ___0.481____ 4. ___276____ 7. ____95.2____ Part C: Extended Response
1. 4.02 g H2O (g)
2. 2.12 kg of glucose
1 atm Solid Liquid Gas
−15°C −10°C 90°C T (°C) 3b. Base on the diagram, the solid-gas line is below the triple point. Hence, sublimation would only happen
below −15°C and below 0.30 atm.
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This note was uploaded on 12/12/2010 for the course ENG CHEM 111 taught by Professor Sternfels during the Spring '97 term at Roane State Community College.
- Spring '97