Unit 5

Vocab

100

A mole

What represents 6.02x10²³ units of a substance?

200

Molar Mass

What is the mass, in grams, of 1 mole of a substance?

300

Avogadro's number

What is 6.02x10²³

400

Empirical Formula

What is the smallest whole-number ratio of elements in a compound? 

500

Molecular Formula

What is the exact formula of a compound, giving the types of atoms and the total number of each?

Conversion Problems

100

The number of moles in 98.5 g of gold.

What is 0.5 moles of Au?

200

The mass of 6.39 moles of table salt, NaCl.

What is 0.11 g of NaCl?

300

How many particles there are in 150 g of CaCO₃

What is 9.02 x 10²³ particles of CaCO₃?

400

How many molecules are in 25 g of ammonia, NH₃.

What is 8.84 x 10²³ molecules NH₃?

500

How many grams there are in 4.3 moles of Na(NO₃)₂

What is 632.09 g of Na(NO₃)₂?

Mass Percent

100

The percent composition of each element when 1.26 g of iron react with 0.54 g of oxygen to form rust.

What is 70% Fe by mass and 30% O by mass?

200

3.4 moles of carbon react with 6.8 moles of oxygen

What is 27% carbon and 73% oxygen?

300

The percent composition by mass for each element in hydrogen peroxide, H₂O₂

What is 94% oxygen and 6% hydrogen?

400

The percent composition by mass for each element in asprin, C₉H₈O₄

What is 60% carbon, 4.5% hydrogen, and 35.5% oxygen?

500

The percent composition of hydrogen in ammonium sulfate, (NH₄)₂SO₄

What is 6.1% hydrogen?

Empirical Formulas

100

The empirical formula of unknown compound is found to have a percent composition of 47% potassium, 14.5% carbon, and 38.5% oxygen

What is KCO₂

200

The empirical formula a compound that contains 15.8% carbon and 84.2% sulfur.

CS₂

300

The empirical formula for a substance containing 209.56 g C, 16.9 g H, and 617.695 g Cl

CHCl

400

The empirical formula for caffeine found from a sample that contains 451.26g carbon, 47.33g hydrogen, 150.30 g oxygen and 263.112 g nitrogen

What is C₄H₅ON₂?

500

The empirical formula of benzoic acid, a compound that contains 68.8% carbon, 4.95% hydrogen, and 26.25% oxygen. 

C₇H₆O₂

Molecular Formulas

100

The molecular formula of a compound with an empirical formula of C₄H₄O, and a molar mass of 136 g/mol.

What is C₈H₈O₂?

200

The molecular formula of a compound that is 9.4 % carbon, 14.9 % fluorine, 62.7% bromine, and 6.3% oxygen that has a formula mass of 237.8 g/mol.

What is C₂F₂Br₂O

300

The molecular formula for NutraSweet, a synthetic sweetener that contains 57.14% carbon, 6.16% hydrogen, 9.52% nitrogen, and 27.18% oxygen. NutraSweet has a molecular formula mass of 294.30 g/mol.

C₁₄H₁₈N₂O₅

400

The molecular formula of Caffeine. A sample contains 49.47% carbon, 5.201% hydrogen, 28.84% nitrogen, and 16.48% Oxygen, and has a molecular formula mass 194.2 g/mol

What is C₈H₁₀N₄O₂?

500

The molecular formula of Nicotine. Nicotine is the main addictive ingredient in cigarettes. A typical cigarette contains 12.33 mg carbon, 1.45 mg H, and 2.87 mg N. The molar mass of nicotine is 162 g/mol

C₁₀H₁₄N₂