Chemical Quantities Multiple Choice Definitions

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

• 3
• 4
• 6
• 8

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

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

• C₆H₆
• C₅H₁₈
• CH
• 6CH

How many moles of silver atoms are in 1.8 x10^20 atoms of silver?

• 3.0 x10 ^-4 mol
• 3.3 x 10 ^-3 mol
• 3.0 x 10_{^2 mol}
• 1.1 x 10^44 mol

What is the empirical formula of a substance that is 53.5%C, 15.5%H, and 31.1% N by weight?

• C_3HN_2
• C_4H_14N_2
• C_2H_7N
• CH_4N_7

What is the number of moles in 9.63 L of H₂S gas at STP?

• .104 mol

• .430 mol

• 3.54 mol

• 14.7 mol

What is the mass in grams of 5.90 mol C_8H_18?

• .0512 g
• 19.4 g
• 673 g
• 389 g

What is the molar mass of (NH₄)_2CO_3 ?

• 144 g
• 138 g
• 96 g
• 78 g