Mole Review Problems (Be sure to SHOW ALL WORK and circle your final
answer for each problem)
The mass of 1 mol of lead atoms is 207.2 g. Find the mass of 1 atom of Pb
3.44 x 10-22 g/atom
You have 1.6 x 1021 molecules of nitrogen gas, N2. How many moles?
2.66 x 10-3 mol
What is the mass of 2.5 moles of silicon?
70.21 g
How many moles of aluminum are present in 180.0 g Al?
6.67 mol
How many moles of chlorine atoms are present in 2.0 grams of chlorine gas, Cl2?
0.0564 mol Cl atoms
A compound with a mass of 48.72 g is found to contain 32.69 g of zinc and 16.03 g of
sulfur. What is the percentage composition of the compound?
67% Zn, 33% S
Calculate the percent composition of H2O
11.2% H, 88.8% O
Calculate the percent composition of K3PO4
K = 55.258%, P = 14.592%, O = 30.150%
Calculate the percent composition of TeCl2
Te = 64.280%, Cl = 35.720%
A sample of a compound is analyzed and found to contain 0.90 g of calcium and 1.60 g
of chlorine. The sample has a mass of 2.50 g. Determine the percentage composition
of the compound
Ca = 36%, Cl = 64%
Mole Review Problems (Be sure to SHOW ALL WORK and circle your final
answer for each problem)
The mass of 1 mol of iron atoms is 55.85 g. Find the mass of 1 atom of Fe
9.277 x 1023 g/atom
You have 1.6 x 1021 molecules of fluorine gas, F2. How many moles?
2.66 x 10-3 mol
What is the mass of 2.5 moles of gallium?
174g
How many moles of potassium are present in 180.0 g K?
4.60 mol
How many moles of silver atoms are present in 25.0 grams of Ag?
0.232 mol
A compound is composed of 36.475% sulfur and 63.525% iron. What is the empirical
formula?
FeS
Calculate the percent composition of Fe(NO3)2
Fe = 31.05%, N = 15.576%, O = 53.374%
Calculate the percent composition of Na3PO4
Na = 42.070%, P = 18.893%, O = 39.037%
Calculate the percent composition of OsCl2
Os = 72.847%, Cl = 27.153%
A sample of a compound is composed of 20.090% sulfur, 39.814% copper, and
40.097% oxygen. What is the empirical formula?
CuSO4