Moles Review

Molar Mass

100

What is the molar mass of Chlorine gas?

70.9 g/mol

200

What is the molar mass of CO₂?

44.01 g/mol

300

What is the molar mass of Ammonium Sulfate? 

132.144 g/mol (NH₄)₂SO₄

400

What is the molar mass of Glucose? (C₆H₁₂O₆)

180.156 g/mol

Conversion

100

What is the mass in grams of 4 moles of helium?

32.064 g He

200

How many moles of carbon dioxide, are in a 22 gram sample of the compound?

0.50 moles CO₂

300

How many moles of hydrogen molecules are present in 9 x 10²³ molecules of hydrogen?

1.49 moles H₂

400

How many molecules of ethane gas are in 15 grams of the compound?

3.0 x 10²³ molecules of C₂H₆

Percent Composition

100

Determine the percentage composition of KMnO₄

K: 24.74% Mn: 34.77%  O: 40.50%

200

Determine the percentage composition of HCl

H: 2.77% Cl: 97.23%

300

Calculate the percent composition of H, P and O in Phosphoric acid

H: 3.09%, P: 31.61%, O: 65.31%

400

What is the percent composition by mass of aspartame (C₁₄H₁₈N₂O₅), the artificial sweetener NutraSweet?

C: 57.14%, H: 6.12%, N: 9.52%, O: 27.21%

Empirical Formulas

100

Determine the empirical formulas for a compound with the following percent compositions:

15.8% carbon and 84.2% sulfur

CS₂

200

Determine the empirical formulas for compounds with the following percent compositions:

40.0% carbon, 6.7% hydrogen, and 53.3% oxygen

CH₂O

300

A compound was found to contain 32.65% Sulfur, 65.3% Oxygen and 2.04% Hydrogen. 

What is the empirical formula of the compound?

SO₄H₂

400

Polymers are large molecules composed of simple units repeated many times. Thus, they often have relatively simple empirical formulas. 

Calculate the empirical formulas of the following polymers:

Orlon; 67.9% C, 5.70% H, 26.4% N

C₃H₃N

Molecular Formulas

100

What is the molecular formula for the compound whose molar mass is 97.0 g/mol and the empirical formula is CH₄?

C₆H₂₄

200

A compound is found to have the empirical formula of CH₂O. If the molar mass is 150.15 g/mol what is the molecular formula?

C₅H₁₀O₅

300

A compound contains 87.4% nitrogen and 12.6% hydrogen. If the molecular mass of the compound is 32.05 g/mol, what is the molecular formula?

Bonus Points for giving the common name!

N₂H₄

400

A major textile dye manufacturer developed a new yellow dye. The dye has a percent composition of 75.95% C, 17.72% N, and 6.33% H by mass with a molar mass of about 240 g/mol. 

Determine the molecular formula of the dye.

C₁₅H₁₅N₃