UNIT 1 WORKSHEET #3 - Portage School's Moodle

Name: __________________________Class: ________________ Date: __________
UNIT 1 WORKSHEET #3
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
____
1. An atomic mass unit (amu) is defined as
a. 1.602 10 -19 C.
b. the mass of 1 mole of hydrogen-1 atoms.
c. the mass of 1 hydrogen-1 atom.
d. the mass of 1 carbon-12 atom.
e. 1/12 the mass of 1 carbon-12 atom.
____ 2. The mass of a single atom of zirconium is 1.515 10 -22 grams. Which is a correct method for
determining the molar mass of Zr?
a.
b.
c.
d.
e. none of the above
____
3. Which is a correct method for determining the total number of atoms in 123 grams of sulfur trioxide
(SO 3 )?
a.
b.
c.
d.
e.
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____
4. Which one of the following is the most effective method of determining isotopic ratios of elements?
a. distillation d. absorption spectroscopy
b. filtration e. mass spectrometry
c. chromatography
____
5. Which of the following samples contains the largest number of atoms?
a. 2.0 moles of H 3 PO 4 c. 4.0 moles of HNO 3 e. 8.0 moles of HBr
b. 3.0 moles of H 2 SO 3 d. 6.0 moles of HClO
____
6. Which is a correct method for determining the mass of carbon present in 0.132 grams of propane
(C 3 H 8 )?
a.
b.
c.
d.
e.
____
7. When propane undergoes complete combustion, the products are carbon dioxide and water.
aC 3 H 8 (g) + bO 2 (g)
cCO 2 (g) + dH 2 O(g)
What are the respective coefficients when the equation is balanced with the smallest whole numbers?
a. a = 1, b = 1, c = 1, d = 1
b. a = 1, b = 1, c = 3, d = 4
c. a = 1, b = 3, c = 3, d = 8
d. a = 1, b = 3, c = 3, d = 4
e. a = 1, b = 5, c = 3, d = 4
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____
8. The catalytic conversion of ammonia to nitric oxide is the first step in a three-step process which
ultimately results in nitric acid. Balance the equation for the reaction.
aNH 3 (g) + bO 2 (g)
cNO(g) + dH 2 O(g)
a. a = 2, b = 1, c = 2, d = 1
b. a = 3, b = 2, c = 3, d = 3
c. a = 4, b = 3, c = 2, d = 6
d. a = 4, b = 5, c = 4, d = 6
e. a = 6, b = 15, c = 6, d = 9
____
9. Aluminum reacts with oxygen to form aluminum oxide. Which of the reactions below is correct and
properly balanced?
a. Al(s) + O(g) → AlO(s)
b. 2Al(s) + O 2 (g) → 2AlO(s)
c. 3Al(s) + O 2 (g) → Al 3 O 2 (s)
d. 4Al(s) + O 2 (g) → 2Al 2 O(s)
e. 4Al(s) + 3O 2 (g) → 2Al 2 O 3 (s)
____ 10. Which method is correct for determining the mass of carbon dioxide that can be made by the
combustion of 3.219 grams of ethanol with excess oxygen?
C 2 H 5 OH(l) + 3O 2 (g) → 2CO 2 (g) + 3H 2 O(l)
a.
b.
c.
d.
e.
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Problem
11. The average molar mass of lithium is 6.941. A sample of lithium consists of two isotopes with
masses of 6.01512 amu and 7.01600 amu. Determine the percent abundance of each isotope.
.
12. The molar mass of nitrogen (N 2 ) is 28.0 g/mole. What is the mass of a single nitrogen atom?
.
13. A 1.45 g sample of chromium contains how many atoms?
.
14. What mass of oxygen is present in 10.0 grams of carbon dioxide (CO 2 )?
.
15. How many moles are present in 0.098 grams of HCl?
.
16. How many atoms are present in 5.00 grams of iron?
.
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17. What is the percent composition of silicon nitride (Si 3 N 4 )?
.
18. Beryl is a mineral which contains 5.03% Be, 10.04% Al, 31.35% Si, and 53.58% O. What is the
chemical formula for beryl?
.
19. Combustion analysis of 2.400 grams of toluene, an organic solvent, yields 8.023 g CO 2 and 1.877 g
H 2 O. What is the simplest formula for toluene?
.
20. Combustion analysis of 0.800 grams of an unknown hydrocarbon yields 2.613 g CO 2 and 0.778 g
H 2 O. What is the percent composition of the hydrocarbon?
.
21. Sodium metal and water react to form sodium hydroxide and hydrogen gas. What mass of Na will
react with excess water to produce 15 g NaOH?
2Na(s) + 2H 2 O(l) → H 2 (g) + 2NaOH(aq)
.
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22. What mass of carbon dioxide can be made by reacting 1.56 grams of sodium bicarbonate with 0.687
grams of hydrochloric acid?
NaHCO 3 (s) + HCl(aq) → CO 2 (g) + H 2 O(l) + NaCl(aq)
.
23. A mass of 8.15 g C 2 H 4 (g) reacts with excess oxygen. If 16.2 g CO 2 (g) is collected, what is the
percent yield of the reaction?
C 2 H 4 (g) + 3O 2 (g) → 2CO 2 (g) + 2H 2 O(g)
.
24. Chlorophyll has one magnesium atom per molecule and is 2.72% magnesium. What is the molar
mass of chlorophyll?
.
25. A mixture of potassium chloride and potassium bromide weighing 3.595 g is heated with chlorine,
which converts it completely into potassium chloride. The total mass of potassium chloride after the
reaction is 3.129 g. What % of the original sample was potassium bromide?
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