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WorksheetsMolar Mass, Percent Composition, and Empirical Formulas
Total questions: 25
Worksheet time: 57mins
Name
Class
Date
1.
What is the molar mass of fluorine gas?
(beware!)
(beware!)
a)
18.998 g/mol
b)
38 g/mol
c)
9 g/mol
d)
18 g/mol
2.
What is the molar mass of table salt (NaCl)?
a)
116.886 g/mol
b)
35.453 g/mol
c)
22.990 g/mol
d)
58.443 g/mol
3.
What is the mass of one mole of aluminum?
a)
27 g
b)
13 g
c)
54 g
d)
14 g
4.
How many particles are in a mole?
a)
602
b)
602 million
c)
602 moles
d)
6.02 x 1023
5.
Calculate the molar mass of Ba(C2H3O2)2
a)
255.3 g/mol
b)
237.3 g/mol
c)
228.3 g/mol
d)
196.3 g/mol
6.
Calculate the molar mass for Al(OH)3
a)
78.0 g/mol
b)
72 g/mol
c)
28 g/mol
d)
25 g/mol
7.
The mass of one mole of substance is called...
a)
molecular mass
b)
mole constant
c)
molar mass
d)
atomic weight
8.
What is the mass of 1 mole of sulfur?
a)
16g
b)
32g
c)
6.02x1023g
d)
1g
9.
What is the mass of 2.4 mol of carbon?
a)
29g
b)
0.20g
c)
5.0g
d)
6.02 x 1023g
10.
How many moles of uranium would 400. grams make?
a)
1.68 mol
b)
0.595 mol
c)
95,200 mol
d)
2.41 x 1026
11.
What is the percent composition by mass of sulfur in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
12.
In which compound is the percent composition by mass of Cl equal to 42%?
a)
HClO (gram formula mass = 52 g/mol)
b)
HClO2 (gram formula mass = 68 g/mol)
c)
HClO3 (gram formula mass = 84 g/mol)
d)
HClO4 (gram formula mass = 100 g/mol)
13.
What is the percent by mass of N in (NH4)2S?
a)
47.1%
b)
68.1%
c)
44.1%
d)
41.1%
14.
Which conversion factor should be used for the following question " How many molecules are there in 4.00 moles of glucose, C6H12O6?
a)
1 mole = 78.12 g
b)
1 mole = 22.4 L
c)
1 mol = 6.02x 1023 particles
d)
more than one
15.
Which conversion factor should be used to solve the following, "How many moles in 28 grams of CO2?"
a)
1 mol = 22.4 L
b)
1 mol = 44.01 g
c)
1 mol = 6.02x1023 atoms
d)
more than one
16.
What is the molar mass of Hydrogen Peroxide (H2O2)?
a)
48 g/mole
b)
34.02 g/mole
c)
36.5 g/mole
d)
35.5 g/mole
17.
How many moles are in 16.94g of water?
a)
16.94 mol H2O
b)
0.9401 mol H2O
c)
305.3 mol H2O
d)
1.063 mol H2O
18.
How many molecules are in 9.44 moles of AlCl3?
a)
5.68 molec AlCl3
b)
5.68x1024 molec AlCl3
c)
0.705 molec AlCl3
d)
1.25x1023 molec AlCl3
19.
What is the mass in grams of 5.90 mol C8H18?
a)
.0512 g
b)
19.4 g
c)
673 g
d)
389 g
20.
Which element has an abundance of 39.03% in the compound sodium phosphate, Na3PO4
a)
Na
b)
P
c)
O
d)
None of the above
21.
A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?
a)
Mg4N3
b)
MgN2
c)
Mg3N2
d)
MgN
22.
How many molecules are in 2.5 mol of NaCl?
a)
1.5 x 1024 molecules
b)
1.5 molecules
c)
4.15 molecules
d)
1.5 x 1023 molecules
23.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6O3 and C2H6O2
d)
CH4 and C2H6
24.
A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?
a)
Mg4N3
b)
MgN2
c)
Mg3N2
d)
MgN
25.
Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?
a)
C2H3O2
b)
CH2O
c)
C2H4O2
d)
C3H8O3
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