Chemistry Questions and Answers Essay

1009 Words Mar 5th, 2014 5 Pages
Name: __________________________ Date: _____________

1.
Suppose the reaction Ca3(PO4)2 + 3H2SO4 3CaSO4 + 2H3PO4 is carried out starting with 103 g of Ca3(PO4)2 and 48.8 g of H2SO4. How much phosphoric acid will be produced?
A)
48.8 g
B)
32.5 g
C)
131.2 g
D)
73.2 g
E)
65.1 g

2.
Naturally occurring element X exists in three isotopic forms: X-28 (27.979 amu, 92.21% abundance), X-29 (28.976 amu, 4.70% abundance), and X-30 (29.974 amu, 3.09% abundance). Calculate the atomic weight of X.
A)
28.09 amu
B)
35.29 amu
C)
28 amu
D)
86.93 amu
E)
25.80 amu

3.
The Claus reactions, shown below, are used to generate elemental sulfur from hydrogen sulfide.

2H2S + 3O2 2SO2 + 2H2O

SO2 + 2H2S 3S + 2H2O

How much
…show more content…
B)
10.6 g of sulfur are formed.
C)
0.0216 moles of H2S remain.
D)
1.13 g of H2S remain.
E)
SO2 is the limiting reagent.

17.
How many grams are in a 4.206-mol sample of sodium hydroxide?
A)
40.00 g
B)
168.2 g
C)
100.9 g
D)
9.510 g
E)
0.1052 g

18.
A given sample of xenon fluoride contains molecules of a single type XeFn, where n is some whole number. Given that 9.03 × 1020 molecules of XeFn weigh 0.311 g, calculate n.
A)
1
B)
2
C)
4
D)
none of these

19.
Which compound contains the highest percent by mass of hydrogen?
A)
HCl
B)
H2O
C)
H2SO4
D)
H2S
E)
HF

20.
Consider the following reaction: 2A + B ® 3C + D
3.0 mol A and 2.0 mol B react to form 4.0 mol C. What is the percent yield of this reaction?
A)
50%
B)
67%
C)
75%
D)
89%
E)
100%

21.
Equal masses (in grams) of hydrogen gas and oxygen gas are reacted to form water. Which substance is limiting?
A)
Oxygen gas is limiting.
B)
Hydrogen gas is limiting.
C)
Water is limiting.
D)
Nothing is limiting.
E)
More information is needed to answer this question.

22.
Adipic acid contains 49.32% C, 43.84% O, and 6.85% H by mass. What is the empirical formula?
A)
C3H5O2
B)
C3H3O4
C)
C2HO3
D)
C2H5O4
E)
C3HO3

23.
One molecule of a compound weighs 2.13e–22 g. Its molar mass is:
A)
2.83 g / mol
B)
7.80e–3 g / mol
C)
120 g / mol
D)
128 g / mol
E)
none of these

24.
A substance, A2B, has the composition by

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