10ADV Moles, Percent composition, Empirical Formula

What percentage of the total atomic mass of magnesium bromide (MgBr₂) is composed of magnesium?

• 13%

• 43%

• 63%

• 87%

What percentage of the total atomic mass of lithium phosphide (Li₃P) is composed of phosphorus?

• 13%

• 29%

• 40%

• 60%

What is the percent by mass of magnesium in MgO?

• 20%
• 40%
• 50%
• 60%

What is the molar mass of table salt (NaCl)?

• 116.886 g/mol
• 35.453 g/mol
• 22.990 g/mol
• 58.443 g/mol

Calculate the molar mass for Al(OH)₃

• 78.0 g/mol

• 72 g/mol

• 28 g/mol

• 25 g/mol

Calculate the molar mass of NH₄NO₂

• 50 g/mol

• 60 g/mol

• 64 g/mol

• 78 g/mol

What is the empirical formula of a substance with the molecular formula C₂H₄?

• C₂H₂

• C₂H₂

• C₁H₁

• CH₂

What is the empirical formula of a substance with the molecular formula NaCl?

• Na₂Cl

• NaCl₂

• NaCl

• Na₂Cl₂

What is the empirical formula of a substance with the molecular formula X₂₀Y₁₅?

• X₁₀Y₁₅

• X₅Y₃

• X₄Y₃

• X₂₀Y₁₅

What is the empirical formula of a substance with the molecular formula Se₈F₁₂?

• Se₈F₁₂

• Se₂F₃

• Se₄F₃

• SeF