Mole Problems
Empirical Formula
Molecular Formulas
Percent Composition
Molar Mass
100

Calculate how many grams are in 0.700 moles of H2O2.

23.8 grams

100

Write the empirical formula for C6H6.

C3H3

100

The molar mass of aniline is 93 g/mol. What is its molecular formula?

C6H7N

100

Find the percent composition for the following compound, N2S2.

N: 30.4%

S: 69.6%

100

Calculate the molar mass of, KOH.

56.1

200

Calculate how many grams are in 1.500 moles of KClO.

135.8 grams

200

Write the empirical formula for C2H6O2.

CH3O

200

If the molar mass of the compound in problem 3 is 73.8 grams/mole, what’s the molecular formula?

Li2CO3

200

Find the percent composition for the following compound, CuBr2.

Cu: 28.45% 

Br: 71.55%

200

Calculate the molar mass of, Cl2.

71

300

Calculate how many grams are in 0.200 moles of H2S.

6.82 grams

300

When 2.5000 g of an oxide of mercury, (HgxOy) is decomposed into the elements by heating, 2.405 g of mercury are produced. Calculate the empirical formula.

Hg2O

300

If the molar mass of the compound in problem 1 is 110 grams/mole, what’s the molecular formula?

C6H6O2

300

Calculate the mass percent of carbon, nitrogen and oxygen in acetamide, C2H5NO.

C %40.6 H %8.5 N %23.7 O %27.1 

300

Calculate the molar mass of, Al2(SO4)3.

310.10 grams

400

Convert 2.50 moles of KClO3 to grams.

306.37 grams

400

A component of protein called serine has an approximate molar mass of 100 g/mole. If the percent composition is as follows, what is the molecular formula of serine? 

C = %34.95 H= %6.844 O = %46.56 N= %13.59  

C3H7NO3

400

A compound with an empirical formula of C2OH4 and a molar mass of 88 grams per mole. What is the molecular formula of this compound?

C4O2H8

400

Find the percent composition for the following compound, NaOH.

Na: 57.48% 

O: 39.99% 

H: 2.53%

400

Calculate the molar mass of, H3PO4.

98

500

Calculate how many grams are in 0.750 moles of NaOH.

29.9 grams

500

Rubbing alcohol was found to contain 60.0 % carbon, 13.4 % hydrogen, and the remaining mass was due to oxygen. What is the empirical formula of rubbing alcohol?

C3H8O

500

A component of protein called serine has an approximate molar mass of 100 g/mole. If the percent composition is as follows, what is the molecular formula of serine? 

C = %34.95 H= %6.844 O = %46.56 N= %13.59  

C3H7NO3

500

Find the percent composition for the following compound, (NH4)2S.

N: 41.1%

H: 11.8%

S: 47.1%

500

Calculate the molar mass of, (NH4)2SO4.

132.1

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