Mid-Quarter Review: Molar Relationships

Calculate the molar mass of Al₂O₃

• 27 g/mol

• 81 g/mol

• 102 g/mol

• 164 g/mol

Calculate the molar mass of Mg(OH)₂

• 38 g/mol

• 58 g/mol

• 64 g/mol

• 74 g/mol

1. How many moles of magnesium are 3.01 x 10²² particles of magnesium? 

• 0.050 moles

• 0.100 moles

• 0.500 moles

• 1.000 moles

1. How many particles are there in 4.00 moles of glucose, C₆H₁₂O₆?

• 2.41 x 10²⁴ particles

• 4.82 x 10²⁴ particles

• 1.45 x 10²⁵ particles

• 2.88 x 10²⁵ particles

1. How many moles are in 28 grams of carbon dioxide, CO₂?

• 0.636 mol

• 0.681 mol

•  0.783 mol

• 0.664 mol

1. What is the mass of 5 moles of sodium chloride, NaCl?

• 292.2 grams

• 58.5 grams

• 0.09 grams

• 264.7 grams

What is the percent composition by mass of each element in CaCO₃? (Molar mass = 100.1 grams)

• 20% Ca, 26.7% C, 53.3% O

• 25% Ca, 30% C, 45% O

• 40% Ca, 12% C, 48% O

• 40% Ca, 10% C, 50% O

What is the percent composition by mass of each element in Fe(NO₃)₂ (molar mass = 179.87 g/mol)

• 21.1% Fe, 15.8% N, 63.2% O

• 25.0% Fe, 22.2% N, 52.8% O

• 31.1% Fe, 15.6% N, 53.4% O

• 33.3% Fe, 11.1% N, 55.6% O

 A compound is found to contain 112.8 g Sb and 164.2 g Cl. What is the empirical formula of this compound?

• SbCl₅

• SbCl₄

• Sb₂Cl₃

• SbCl₂

A compound is found to contain 52.44 g C and 209.56 g O. What is the empirical formula of this compound?

• CO₃

• CO₂

• C₂O₄

• CO₄