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WorksheetsCHEM Unit 8 Exam Review
Total questions: 18
Worksheet time: 5hrs 30mins
Name
Class
Date
1.
Which of the following is equivalent to the mole? Select all that apply.
a)
6.022 x 10^23
b)
Avagadro's Number
c)
1,000 grams
d)
Dozen
2.
What is the empirical formula for the compound, C2H6?
a)
CH3
b)
CH2
c)
C2H2
d)
C3H3
3.
Which of the following best describes an empirical formula?
a)
The simplest, whole number ratio of elements in a compound
b)
The formula which represents the actual number of atoms of each element in a compound
4.
Which of the following best describes a molecular formula?
a)
The simplest, whole number ratio of elements in a compound
b)
The formula which represents the actual number of atoms of each element in a compound
5.
Which of the following is a hydrous compound?
a)
Copper (II) Sulfate Penthydrate
b)
Carbon Monoxide
c)
Lithium Bromide
6.
A compound has a molar mass of 430 g/mol and an empirical formula of C3H7. What is its molecular formula?
a)
C3H7
b)
C15H7
c)
C15H35
7.
How many moles are in 3.01 x 10^22 atoms of magnesium?
a)
0.0500 mol Mg
b)
1.81 x 10^24 mol Mg
c)
5 x 10^-22 mol Mg
8.
How many atoms are in 0.750 moles of zinc?
a)
1.25 x 10^-24 atoms
b)
4.52 x 10^23 atoms
c)
8.03 x 10^23 atoms
9.
What is the % composition of oxygen in copper (II) sulfate?
a)
159.61 g/mol
b)
0.075
c)
0.4
d)
0.67
10.
A compound is found to contain 63.52 % iron and 36.48% sulfur. Find its empirical formula.
a)
Fe2S
b)
FeS2
c)
FeS
11.
A 170.00 g sample of an unidentified compound contains 29.84 g sodium, 67.49 g chromium, and 72.67 g oxygen. Find the empirical formula.
a)
NaCrO
b)
NaCr2O7
c)
Na2Cr2O7
12.
What is the mass of 0.600 mol of oxygen gas?
a)
12.01 g
b)
19.2 g
c)
25.3 g
13.
A compound is found to be 49% carbon, 6.7% hydrogen, and 53.5% oxygen. Its molecular mass is 60 g/mol. What is its molecular formula?
a)
C5H5O2
b)
C2H4O2
c)
CH2O
14.
Think of formula units as particles. If there are 4.5 x 10^24 formula units of sulfur dioxide, how many grams of sulfur dioxide are there?
a)
7.47 grams
b)
64 grams
c)
478 grams
d)
4.22x10^45 grams
15.
What is the molar mass of Potassium Oxide?
a)
55.1 g/mol
b)
71.1 g/mol
c)
94.2 g/mol
16.
A hyddrous compound has a mass of 10 g. After heat is applied, the substance has a mass of 8.4 grams. What is the mass of the hydrate attached?
a)
2.5 grams
b)
10 grams
c)
8.4 grams
d)
1.6 grams
17.
A hydrate is a crystal with what attached to it (chemically)?
a)
sulfur
b)
hydrogen
c)
hydroxide
d)
water
18.
Anhydrous lithium perchlorate (LiClO4) with a mass of 4.78 g was dissolved in water and recrystallized. The mass of the hydrated salt obtained was 7.21 g. What is the name of the hydrous compound?
a)
lithium perchlorate dihydrate
b)
lithium perchlorate tetrahydrate
c)
lithium perchlorate trihydrate
d)
lithium perchlorate monohydrate
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