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X211SPG17 I 0406 -Stoichiometry, Gas Laws & Thermochemistry.dy

1. A 5.95-g sample of AgN03 is reacted with Bac12 according to the equation

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2AgN03(czg) + Bac12(czg) + 2Agcl(s') + Bao{03)2(czg)

to give 3.36 g of Agc1. What is the percent yield of Agcl?A) 44.6%8) 33.5%C) 66.9%D) 56.5%E) 100%

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2. What is the change in enthalpy at 25°C and 1 atm for the production of 9.00 mol Sno(s)?

Sn(s) + Sn02(f) i 2Sno(S); AIZ° = 16.2 kJ

A) -72.9kJ8) -16.2kJC) 16.2kJD) 1.80kJE) 72.9kJ

3. What is the change in enthalpy at 25°C and 1 atm for the reaction of 5.00 mol of elemental ironwith excess oxygen gas?

4Fe(5) + 302(g) i 2Fe203(s'); Aft = -1651 kJ

A) -1651kJa) 2752kJC) 2064kJD) -2064kJE) -412.8kJ

4. A 1.067 g sample of an element contains 5.062 x 1021 atoms. What is the element symbol?

X211SPG17-0406 ID:8

5. The amount of calcium in a 15.0-g sample was determined by converting the calcium to calciumoxalate, Cac204. The Cac204 weighed 12.6 g. What is the percent of calciuni in the originalsample?A)a) 26.3%C) 14.8%D) 33.7%E) 84.0%

Eii:==i 6. What volume of ammonia gas, measured at 660.3 mmHg and 58.2°C, is required to produce 6.46 g

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of ammonium sulfate according to the following balanced chemical equation?

2NH3(g) + H2S04(CZ9) + OJH4)2S04(J)

0.000781 L0.00312 L0.765 L11.9 L

3.06 L

2KHC03(S) + K2C03(S) + C02(g) + H200

How many moles of potassium carbonate will be produced if 454 g of potassiuni hydrogencarbonate are heated?A) 2.27mol8) 3.29molC) 11.4molD) 227molE) 4.54mol

8. Ammonia, NH3, and oxygen can be reacted together in the presence of a catalyst to form onlynitrogen monoxide and water. The number of moles of oxygen consumed for every 5.00 moles ofNO produced isA) 6.258) 25.0C) 18.8

D) 3.13

E) 12.5

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9. What is Afro of the following reaction?

C02(8) + 2CH4(8) + C3H8(g) + 02(8)

Substance Afro/(kJ/mol)C02(g) -393.5CH4(g) -74. 9C3H8(g) -104.7

A) -348.4kJ8) -573.1kJC) 438.6kJD) 348.4kJE) nd48.okT

10. A 9.020-g sample of an unknown metal M is burned in the presence of excess oxygen, producingthe oxide M203(s) and liberating 191.5 kJ of heat at constant pressure. What is the identity of themetal?

4M(s) + 302(g) i 2M203(S)

SubstanceYb203(S)Tb203(S)Sm2o3(S)SC203(S)Y203(S)

11.

AIJO/(kJ/mol)-1814.6-1865.2-1823.0-1908.8-1905.3

What is the percent by mass oxygen in (N114)2S03?

A)8) 20.7%C) 54.0%D) 42.0%E) 1.000/o

X211SPG17-0406

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12. An excess of sodium hydroxide is treated with 2.4 L of dry hydrogen iodide gas measured at STP.What is the mass of sodium iodide is formed?

19g

13. Analysis of a compound showed that it contained 76.0 % fluorine atoms and 24.0 % carbon atomsby mass. What is its empirical formula?

a)C)D)E)

14. What is the mass in grams of one propene, C3H6, molecule?

A) 6.99x |o-23g8) 2.53x|o25gC) 44.0gD) 42.0gE) 1.99x|o-23g

i; 15. A given mass of gas occupies a volume of 4.00 L at 60°C and 550 mmHg. Which of the following4j ri , ` mathematical expressions will yield its temperature at 3.00 L and 775 mmHg?

^` ,^^~ 4.00L 775nmHgA) 60°C x ;.:: T-X3.00 L ' 550 nmHg

8) 333Kx#x

C) 333Kx#x

D) 333Kx#x

E) 333Kx#x

550 nrmg775 ImHg775 nrdg550 nmHg775 nrmg550 nrmHg

550 rmnHg

775 rmnHg

1.00-L sample of a gas at STP has a mass of 1.16 g. The molar mass of the gas is5 .18 g/mol.26.0 g/mol.22.4 g/mol.44.8 g/mol.193 g/mol.

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17. A sample of methane, CH4, occupies a volume of 170.0 mL at 25°C and exerts a pressure of965.0 mmHg. If the volume of the gas is allowed to expand to 720.0 mL at 298 K, what will be thepressure of the gas?A) 4090mmHg8) 2720mmHgC) 227.8mmHgD) 0.008823 mmHgE) 550.OmmHg

18. What is the quantity of heat evolved at constant pressure when 60.3 g H20(D is formed from thecombustion of H2(g) and 02(g)?

H2(g) + +02(g) i H200; Afz° = -285.8 kJ

A) 1.17xl0-2kT

8) 285.8kJ

C) 1.72xl04klD) 85.4kJ

E) 9.57xl02kT

How many moles of pentane, C5Hi2, are contained in a 11-g sample?0.18 mol0.15 mol0.26 mol1.4 mol1.1 mol

20. What quantity, in moles, of hydrogen is consumed when 676.8 kJ of energy is evolved from thecombustion of a mixture of H2(g) and 02(g)?

H2(g) + +02(g) + H20(O; Afro = -285.8 kJ

A) 2.368mol8) 1.184molC) 0.4223molD) 3.368molE) 1.368mol

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X211SPG17-0406

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21. The following equation represents the partial combustion of methane, CH4.

2CH4(g) + 302(g) + 2CO(g) + 4H20®

At constant temperature and pressure, what is the maximum volume of carbon monoxide that can

be obtained from 3.39 x 102 L of methane and 1.70 x 102 L of oxygen?

A) 5.09x|02L

8) 3.39xl02L

C) 1.19xl03L

D) 1.13xl02L

E) 6.78xl02L

22. A gas occupies a volurne of 2.00 L at 860 mmHg and 30.0°C. Which of the followingmathematical expressions will yield its volume at STP?

A) 2.00Lx

8) 2.00Lx

C) 2.00Lx

D) 2.00Lx

E) 2.00Lx

860ImHg 273KX

760nrmg-303K760nmHg 298K

X860nrmg' 303K860rmnHg 303K

X760mmHg 273K760ImHg 303K

X860rmHg' 273K760nndg 273K

X860mmHg 303K

23. A sample of an oxide of antimony (Sb) contained 39.5 g of antimony combined with 13.0 g ofoxygen. What is the simplest formula for the oxide?A) Sb02

How many moles of gas are in a gas sample occupying 0.738 L at 135 mmHg and 30°C?A) 190mol8) 4.01molC) 40.5molD) 0.00527molE) 0.000433 mol

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X211SPG17-0406 ID:8

25. An ore sample with a mass of 68.0 g is found to contain 15.5% by mass nickel. What mass ofnickel is contained in the ore?

r7= 26.

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How much heat is liberated at constant pressure when 58.5 g of calcium oxide reacts with 83.9 L ofcarbon dioxide gas, measured at 1.00 atm pressure and 25.0°C? (A = 0.0821 L . atm/(K . mol))

Cao(a) + C02(g) + Cac03(s); AffJ = -178.3 kJ

nd.1 1 x 102 k|

-1.04 x 104 kT

-7.97 x 102 kT

-1.86 x 102 kT

-1.50 x 104 kT

What is the change in enthalpy when 4.00 mol of sulfur trioxide decomposes to sulfur dioxide andoxygen gas?

2S02(g) + 02(g) + 2S03(g); AH° = 198 kJ

A) 396kJ8) -198kJC) -396kJD) 198kJE) 792kJ

£[.- 28. What is AI7° forthe following reaction?-..--,-.--.,..I, 2C2H2® + 502(g) + 4C02(g) + 2H200

S ub stanc e AI7°/ (kJ/mo I)C2H2(g) +226. 7C02(g)H20®

A) +1692.2kJa) 452.6kJC) -1692.2kJD) +2599.OkJE) -2599.OkJ

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X211SPG17-0406

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29. When 20.0 g C2H6 and 60.0 g 02 react to form C02 and H20, how many grams of water areformed?A) 14.5g8) 58.0gC) 18.0g

D) 20.0gE) none of these

30. The commercial production of phosphoric acid, H3P04, can be represented by the equation

15009 3009 3079 11809 300gCa3(P04)2 + 3Si02+ 5C + 502+ 3H20 + 3Casi03 + 5C02 + 2H3P04310g/mol 60.1 12.0 32.0 18.0

g/mo I g/mo I g/mo I g/mo I

The molar mass for each reactant is shown b£±Q!Lw the reactant, and the mass of each reactant forthis problem is given a!Q]£§. Which substance is the limiting reactant?A) H20B)CC)02D) Ca3(P04)2E) Si02

3 1 . Which of the following gases will have the slowest rate of effusion at constant temperature?

32. At 25°C, the standard enthalpy of combustion of gaseous propane (C3H8) is -2219.0 kJ per mole of•--_J=?: propane, and the standard enthalpy of combustion of gaseous propylene (C3H6) is -2058.3 kJ per

mole of propylene. What is the standard enthalpy change for the following reaction at 25°C?

C3H6(8) + H2(8) + C3H8(8)

Substance AZZ°/ (kJ/mol)C02(g)H20®

A) +104.7kJa) -20.4kJC) -125.1kJD) +160.7kJE) -160.7kJ

-393.5-285.8

X211SPG17-0406 ID:8

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±==:= 33. What is the total volume of gases produced at 819 K and 1.00 atm pressure when 320 g ofammonium nitrite undergoes the following decomposition reaction?

NH4N02(I) + N2® + 2H20(g)

A) 3x22.4L8) 22.4LC) 15x22.4LD) 5x22.4LE) 45x22.4L

Of the following, the only empirical formula isA) C4H,o.

C4H6.

C5H14.

H202.02.

35. If 250 mL of methane, CH4, effuses through a small hole in 28 s, the time required for the samevolume of helium to pass through the hole under the same conditions will be

36. The density of ethane, C2H6 (30.1 g/mol), at 32°C and 1.31 atm pressure isA) 1.57g/L.8) 19.2g/L.C) 1.34gth.D) 0.635gIT.E) 0.162g/L.

37. What is the pressure of a 59.6-L gas sample containing 3.01 mol of gas at 44.9°C?(j2 = 0.0821 L . atm/(K . mol),1 atm = 760 torr)A) 1.41xl02mmHg

8) 1.73x 10-3mmHgC) 1.32mmHg

D) 1.00x l03mmHg

E) 5.77x l02mmHg

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X211SPG17-0406

ic:rf~38.ca|cu|atethenumberofmolesofbrominepresentin14.5mLofBr2(D,Whosedensityis

`...-.-''+-.--i3 .12 g/mL.A) 3.53mol8) 0.181molC) 0.566molD) 0.091molE) 0.283mol

f' 39. From the following information, determine AI7°/ofmalonic acid, CH2(COOH)2(s).

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CH2(COOH)2(J) + 202(g) i 3C02(g) + 2H200; Afro = -861.0 kJ

Substance AIZ°/(kJ/mol)C02(g)H20®

-393.5-285.8

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A) 2613kJ8) 891.1kJ

C) -1540.3kJD) -2613.1kJE) -891.1kJ

40. According to the following thermochemical equation, if 951.1 g of N02 is produced, how muchheat is released at constant pressure?

2NO(g) + 02® i 2N02G); AZ7° = -114.4 kJ

A) 114.4kJ

8) 1.183xl03kT

C) 2.365xl03kTD) 5.534kJ

E) 1.088xl05kT

A particular compound contains, by mass, 41.4 % carbon, 3.47 % hydrogen, and 55.1 % oxygen.A 0.050-mol sample of this compound weighs 5.80 g. The molecular formula of this compound isA) C3H303.

a) C3H30.C) CHO.D) C4H404.E) C5H505.

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