Worksheets% Composition
Total questions: 11
Worksheet time: 37mins
Name
Class
Date
1.
What is the percent by mass of sodium in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
2.
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)
3.
How many moles are in 19.82 g Mg?
a)
1.23 mol Mg
b)
481.70 mol Mg
c)
1.00 mol Mg
d)
0.82 mol Mg
4.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6O3 and C2H6O2
d)
CH4 and C2H6
5.
What is the molar mass of PbSO4
a)
303.3 g/mol
b)
294.7g/mol
c)
163.8g/mol
d)
372g/mol
6.
What is the percentage of chromium in K2Cr2O7?
a)
38.1%
b)
27.2%
c)
34.7%
d)
100%
7.
What is the percent composition of S in the formula (NH4)2S ?
a)
12.05%
b)
19.30%
c)
47.11%
d)
56.18%
8.
What is the empirical formula for the following:
Pb5Cr5O20
Pb5Cr5O20
a)
Pb2Cr2O10
b)
PbCr2O7
c)
Pb9Cr4O2
d)
PbCrO4
9.
What is the percent composition of water?
a)
H = 11.1%
O = 89.9%
O = 89.9%
b)
H = 66.7%
O = 33.3%
O = 33.3%
c)
H = 5.6%
O = 89.9%
O = 89.9%
d)
H = 20%
O = 80%
O = 80%
10.
What is the percent composition of aluminum phosphate?
a)
Al = 25%
P = 25%
O = 75%
P = 25%
O = 75%
b)
Al = 22.1%
P = 35.8%
O = 42.1%
P = 35.8%
O = 42.1%
c)
Al = 14.3%
P = 25.4%
O = 60.3%
P = 25.4%
O = 60.3%
d)
Al = 22.1%
P = 25.4%
O = 52.5%
P = 25.4%
O = 52.5%
11.
What is the % Iron from an iron ore sample based on the following data:
Crucible Mass = 126.45 g
Crucible & Ore Mass = 254.82 g
Mass of Metal & Filter = 34.75 g
Mass of Filter = 23.61 g
Crucible Mass = 126.45 g
Crucible & Ore Mass = 254.82 g
Mass of Metal & Filter = 34.75 g
Mass of Filter = 23.61 g
a)
22.41%
b)
8.68%
c)
18.29%
d)
0.377%
100 %
