Unit 2 Chemistry

What is the percent by mass of oxygen in MgO?

• 20%

• 40%

• 50%

• 60%

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

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

What is the molar mass of CO₂?

• 12

• 16

• 32

• 44

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 for Al(OH)₃

• 78.0 g/mol

• 72 g/mol

• 28 g/mol

• 25 g/mol

What is the percent by mass of sodium in NaCl?

• 39%

• 61%

• 35%

• 65%

What percentage of the total atomic mass of carbon monoxide (CO) is composed of carbon?

• 29%

• 43%

• 57%

• 73%