R = 0.08206 L.atm/mol.K      R = 8.314 J/mol.K      1 atm = 760 Torr
PV = nRT      Pi = ciP      ci = ni/n         q = CDT
M = m/n      d = m/V      d = MP/RT         q = mCsDT
vrms = (3RT/M)1/2             teff(A)/teff(B) = (MA/MB)1/2   
DH° = S nDHf°(products) - S nDHf°(reactants)




1. A 2.50 L sample of neon has a pressure of 1.59 atm at 45.0°C. What volume would the sample have if the pressure is 725 Torr and the temperature 22.0°C?
A.3.07 L
B.1.62 L
C.3.87 L
D.2.04 L
E.0.733 L


2. Ammonia burns in air as follows:
   4NH3(g) + 3O2(g) ® 2N2(g) + 6H2O(g)
How many liters of N2(g) are formed by burning 2.50 L of ammonia in excess oxygen with all species at the same temperature and pressure?
A.2.00 L
B.2.50 L
C.1.25 L
D.5.00 L
E.0.625 L


3. A 5.00 L sample of xenon gas has a pressure of 155 Torr at –90°C. What mass of Xe is present?
A.0.0880 g
B.8.92 g
C.4.53 g
D.6.78 × 103 g
E.18.1 g


4. What is the molar volume of nitrogen at 300°C and 0.500 atm?
A.94.0 L
B.47.0 L
C.188 L
D.49.2 L
E.22.4 L


5. What volume of CO2(g) at 25°C and 760 Torr is produced when 1.00 kg of calcium carbonate is used to neutralize a sulfuric acid spill? The equation for the reaction is
   CaCO3(s) + H2SO4(aq) ® CaSO4(s) + CO2(g) + H2O(l)
A.321 L
B.122 L
C.488 L
D.22.4 L
E.244 L


6. The volume of 2.81 g of an unknown gas is 2.25 L at STP. What is the molar mass of the gas?
A.100 g/mol
B.17.9 g/mol
C.142 g/mol
D.50.4 g/mol
E.28.0 g/mol


7. Which of the following gases has the lowest density at STP?
A.acetylene, C2H2
B.NO2
C.SO3
D.chlorine
E.argon


8. Calculate the density of nitrogen at 695 Torr and –15°C.
A.1.08 g/L
B.9.07 g/L
C.2.42 g/L
D.1.21 g/L
E.0.605 g/L


9. A gas mixture contains 0.0500 moles of hydrogen, 0.0400 moles of carbon dioxide, and 0.0325 moles of nitrogen in a 2.00 L flask. If the total pressure in the flask is 1000 Torr, what is the partial pressure of carbon dioxide?
A.1.32 atm
B.0.327 atm
C.0.430 atm
D.0.161 atm
E.0.215 atm


10. Which gaseous molecules (choose one species) effuse slowest?
A.SO2(g)
B.Ar(g)
C.NO(g)
D.Ne(g)
E.CO2(g)


11. Calculate DU for a system that loses 325 kJ of heat while doing 200 kJ of work on the surroundings.
A.–125 kJ
B.+125 kJ
C.0 kJ
D.+525 kJ
E.–525 kJ


12. A piece of graphite of mass 75.0 g at 92.0°C was placed in a calorimeter that contained 200.0 g of water at 12.0°C. If the temperature of the water rose to 16.8°C, what is the specific heat capacity of graphite? The specific heat capacity of water is 4.184 J·(°C)–1·g–1.
A.0.71 J·(°C)–1·g–1
B.3.2 J·(°C)–1·g–1
C.2.5 J·(°C)–1·g–1
D.0.58 J·(°C)–1·g–1
E.4.5 J·(°C)–1·g–1


13. A calorimeter containing 200 mL of water was calibrated by carrying out a reaction which released 15.6 kJ of heat. If the temperature of the calorimeter rose 3.25°C, what is the heat capacity of this calorimeter?
A.24.0 kJ (°C)–1
B.4.80 kJ (°C)–1
C.2.58 kJ (°C)–1
D.0.960 kJ L (°C)–1
E.8.37 kJ (°C)–1


14. At 0°C the enthalpy of melting of water is 6.0 kJ·mol–1. The enthalpy change when 36 g of water freezes is
A.–6.0 kJ
B.+6.0 kJ
C.–12 kJ
D.–216 kJ
E.+12 kJ


15. When 9.00 g of methane, CH4(g), is burned in a constant pressure calorimeter with a heat capacity of
66.0 kJ·K–1 , the temperature of the calorimeter assembly rises by 7.59 K. What is the standard enthalpy of combustion of methane?
A.–281 kJ·mol–1
B.–1252 kJ·mol–1
C.–891 kJ·mol–1
D.–31.3 kJ·mol–1
E.–501 kJ·mol–1


16.

Calculate the reaction enthalpy for


2PbO(s) + O2(g) ® 2PbO2(s)

from the data


2Pb(s) + O2(g) ® 2PbO(s)

DH° = -435.8 kJ


Pb(s) + O2(g) ® PbO2(s)

DH° = -276.6 kJ


A.-117.4 kJ
B.+159.2 kJ
C.-159.2 kJ
D.+117.4 kJ
E.-595.0 kJ


17. If the standard enthalpy of combustion of C(s) is –394 kJ·mol–1, calculate the mass of C(s) needed to supply 550 kJ of heat.
A.8.60 g
B.32.8 g
C.0.716 g
D.18.2 g
E.16.8 g


18. Which thermochemical equation gives the value of the standard enthalpy of formation for NaN3(s)?
A.2Na(s) + 3N2(g) ® 2NaN3(s)
B.Na(l) + 3/2N2(g) ® NaN3(s)
C.Na(s) + 3/2N2(g) ® NaN3(s)
D.Na(g) + 3N(g) ® NaN3(s)
E.Na(s) + 3N(g) ® NaN3(s)


19. Which of the following has a standard enthalpy of formation equal to zero?
A.Hg(l)
B.Na(l)
C.I2(g)
D.C(g)
E.S(g)


20. The standard enthalpy of formation of NO(g) is +90.3 kJ·mol-1 and that of NO2(g) is +33.2 kJ·mol-1.
Calculate the reaction enthalpy for
   2NO(g) + O2(g) ® 2NO2(g)
A.-47.8 kJ
B.-57.1 kJ
C.+123.5 kJ
D.-23.9 kJ
E.-114.2 kJ



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