Name___________________________________
Stoichiometry
DIRECTIONS: Circle the answer that best completes each statement.
1. One mole of Ca3(PO4)2 contains
(a) one mole of calcium.
(b) three moles of calcium.
(c) four moles of oxygen.
(d) two moles of phosphorus.
a only b&c b&d b only
2. One mole of ammonia (NH3) contains
(a) 6.02 X 1023 atoms of nitrogen.
(b) 14.01 g of nitrogen.
(c) 7.0 g of nitrogen.
(d) 6.02 X 1023 molecules.
a,b&d a,c&d a&b d only
3. Which of the following has the greatest mass?
(a) 200 molecules of water.
(b) 100 atoms of Fe.
(c) 200 molecules of O2.
(d) 200 molecules of CH4.
a b c d
4. Which of the choices in Question 3 has the least mass?
a b c d
5. Vitamin C, C6H8O6,
(a) has an empirical formula of C3H4O3.
(b) contains 40.92% carbon by mass.
(c) contains 6 moles of carbon atoms per mole of molecules of Vitamin C.
(d) has a molecular mass of 176.12.
a&c a,c&d a,b&c all of
the above
6. Which of the following compounds contains the highest mass
percent of nitrogen?
(a) NO
(b) NO2
(c) N2O3
(d) N2O
a b c d
7. Which compound in Question 6 contains the lowest mass percent of nitrogen?
a b c d
8. A compound whose empirical formula is NPCl2 has a molecular
weight of 347.66. What can be concluded about its molecular formula?
(a) It is NPCl2.
(b) It is N2P2Cl2.
(c) It is N3P3Cl6.
(d) No conclusion can be made.
a b c d
9. When the equation
__UO2(s) + __HF(l)------------->__UF4(s) + __H2O(l)
is balanced, each mole of UO2(s) yields how many moles of water?
(a) 1
(b) 2
(c) 3
(d) 4
a b c d
10. When the equation
__PH3(g) + __O2(g)------------->__P4O10(s) + __H2O(l)
is balanced, the number of moles of water produced for each mole of P4O10(s)
produced is
(a) 1
(b) 4
(c) 6
(d) 10
a b c d
11. When the equation
__Ca(OH)2(aq) + __H3PO4(aq)-------------->__H2O(g) + __Ca3PO4)2(s)
is balanced, the number of moles of water produced for each mole of calcium
phosphate produced is
(a) 1.
(b) 2
(c) 6
(d) 10
a b c d
12. Consider the reaction
Mg(s) + I2(s) ------> MgI2(s)
Under which of the following reaction conditions will Mg be the limiting reagent?
(a) 200 atoms of Mg and 300 molecules of I2
(b) 0.16 mol Mg and 0.25 mol I2
(c) 100 atoms of Mg and 100 molecules of I2
(d) 0.12 mol Mg and 0.08 mol I2
a,b&c c&d a&c a&b
13. Consider the reaction
2 SO2(g) + O2(g) -------> 2 SO3(g)
What is the largest number of SO3 molecules which could be made from
381 SO2 molecules and 185 O2 molecules?
(a) 381
(b) 370
(c) 185
(d) 92
a b c d
14. One atom of an element has a mass of 9.123 X 10-23 g. There is only
one isotope of the element. The element is
(a) manganese.
(b) chlorine.
(c) chromium.
(d) argon.
a b c d
15. If the fertilizers listed below are priced according to their nitrogen
content, which will be the least expensive per 50 lb. bag?
(a) urea (NH2)2CO
(b) ammonia NH3
(c) ammonium nitrate NH4NO3
(d) guanidine HNC(NH2)2
a b c d
16. The equation
CH4(g) + 2 O2(g) ---------> CO2(g) + 2 H2O(g)
(a) is balanced.
(b) is a combustion reaction.
(c) results in 80 g of products for each 80 g of reactants consumed.
(d) describes a chemical change.
a,b&d a&b b&d all of
the above
17. One mole of (NH4)2Cr2O7 contains
(a) one mole of nitrogen.
(b) eight moles of hydrogen.
(c) one mole of chromium.
(d) seven moles of oxygen.
a&c b&d a&d b&c
18. Which of the following statements are true?
(a) 1 mol H atoms = 6.02 X 1023 H atoms.
(b) 1 mol pennies = 6.02 X 10 23 pennies.
(c) 6.02 X 1023 H atoms have a mass of 1.008 g.
(d) The formula mass of O2 = 32.00 amu.
a,b&c a&b b&c all of
the above
19. Which of the following has the largest mass of carbon per gram
of substance?
(a) H2CO3
(b) CH3CO2H
(c) CH3OH
(d) CH3CH2OH
a b c d
20. Which substance in Question 19 has the lowest mass of carbon per gram
of substance?
a b c d
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Answers:
1. b&d 2. a,b&d 3. c 4. d 5. all 6. d 7. b 8. c 9. b 10. c
11. c 12. a&b 13. b 14. a 15. c 16. all 17. b&d 18. all 19. d 20. a
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