Moles from Chemical Formulas

What is the SI unit for a count of atoms?

• meter
• mass
• molecule
• mole

How many hydrogen atoms are in the compound: (NH₄)₂CO₃

• 3
• 4
• 6
• 8

What is the formula mass of CO₂?

• 44 grams
• 44 amu
• 0.44 grams
• 2.6 x 10²⁵ atoms

What is the percent composition of nitrogen in NH₃?

• 25%
• 14%
• 28%
• 82%

Which of the following is an empirical formula?

• C₃H₃
• Li₂CO₃
• Na₂O₂
• C₆H₁₂O₆

How many moles are contained in 45 grams of aluminum?

• 27 mol
• 1215 mol
• 1.7 mol
• 57 mol

How many moles of chlorine gas are contained in 45 grams of pure sample?

• 35 mol
• 0.64 mol
• 1.3 mol
• 2.6 mol

How many atoms of are contained in a mole of sodium?

• 6.02 x 10²³ atoms
• 11 atoms
• 23 atoms
• 2 atoms

If the empirical formulas is CH and the molar mass is 78g/mol, what is the molecular formula?

• C₆H₆
• C₅H₁₈
• CH
• 6CH

1 mol = 6.02 x 10²³ _______

• particles

• grams

• liters

• Kelvin