Percent Composition and Mole Calculation

Which of the following methods should be used in order to calculate the molar mass of magnesium hydroxide?

• Add the masses of two moles Mg to the mass of one mole OH

• Add the total protons and neutrons.

• Add the masses of one mole Mg to the mass of one mole OH

• Add the masses of one mole Mg to the masses of two moles of OH.

Tags

NGSS.HS-PS1-7

What is the percent by mass of sodium in NaCl?

• 39%

• 61%

• 35%

• 65%

What is the percent by mass of magnesium in MgO?

• 20%

• 40%

• 50%

• 60%

Tags

NGSS.HS-PS1-7

What is the percent composition by mass of magnesium in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%

• 27%

• 46%

• 53%

What is the percent composition by mass of oxygen in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%

• 27%

• 46%

• 53%

What is the percent by mass of Cu in CuBr₂?

• 50%

• 71.6%

• 28.4%

• 44.3%

Find the percent composition of CaCl₂?

• Ca: 36.11%; Cl: 63.88%

• Ca: 53.12%; Cl: 100%

• Ca: 36.11%; Cl: 83.56%

• Ca: 46.11%; Cl: 63.88%

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

• 29%

• 43%

• 57%

• 73%

What is the percent composition by mass of hydrogen in water (H2O)?

• 11.1%

• 33.3%

• 66.7%

• 88.9%