S4 Chemistry Chapter 6 Reviewer (Term 2)

What is the percent by mass of magnesium in MgO?

• 20%

• 40%

• 50%

• 60%

Find the percent composition of Cu₂S?

• %Cu= 67.987

  %S= 32.013

• %Cu= 79.854

  %S= 20.145

• %Cu= 35.946

  %S= 64.054

• %Cu= 35.946

  %S= 75.190%

How many percent of chlorine is present in chloroform, CHCl₃?

• 10.06%

• 0.84%

• 89.09%

• 99.99%

What is the percent composition of Benzene, C₆H₆?

• C = 50%

  H = 50%

• C = 85.7 %

  H = 14.3%

• C = 92.2%

  H = 7.8%

• C = 71.9%

  H = 28.1%

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 of Ba(C₂H₃O₂)₂

• 255.3 g/mol

• 237.3 g/mol

• 228.3 g/mol

• 196.3 g/mol

A compound consists of 72.2% Mg and 27.8% N by mass. What is its empirical formula?

• Mg₄N₃
• MgN₂
• Mg₃N₂ 
• MgN

How many molecules are in 2.5 moles of NaCl?

• 1.5 x 10²⁴ molecules

• 1.5 molecules

• 4.15 molecules

• 1.5 x 10²³ molecules

Glycerol has a molar mass of 92.09 g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?

• C₂H₃O₂
• CH₂O
• C₂H₄O₂
• C₃H₈O₃

What is the molecular formula for a compound with an empirical formula of K₂SO₄ and a molecular mass of 696 g?

• K₂SO₄ 
• K₈SO₁₆
• K₈S₄O₈ 
• K₈S₄O₁₆