Hydrates & Percent Comp

Find the percentage composition of Mg in Mg₃(PO₄)₂.

• 27.48% Mg

• 43.11% Mg

• 16.00% Mg

• 12.63% Mg

The mass % of aluminum in aluminum sulfate Al₂(SO₄)₃ is:

• 12.93%

• 45.70%

• 7.89%

• 35.94%

• 15.77%

A sample of a compound contains 9.0 g of aluminum, 28.0g of sulfur, and 64.0g of oxygen. What is the percent composition by mass of sulfur in the compound?

• 20%

• 28%

• 30%

• 33%

What is the percent composition of nitrogen in ammonium sulfide?

• 41.10%

• 20.55%

• 27.95%

• 18.18%

A hydrate of magnesium chloride is present and the following data is collected:
mass of crucible = 22.130 grams
mass of crucible + hydrate = 25.290 grams
mass of crucible and contents after heating = 23.491 grams
What is the complete formula of this hydrate?

• MgCl₂ · 7H₂O
• MgCl₂ · 11H₂O
• MgCl₂ · 6H₂O
• MgCl₂ · 13H₂O

Tags

NGSS.HS-PS3-4

A 15.67 g sample of a hydrate of magnesium carbonate was heated to drive off the water. The mass was reduced to 7.58 g. What is the formula of the hydrate?

• MgCO₃ · 5H₂O
• MgCO₃ · 4H₂O
• MgCO₃ · 6H₂O
• MgCO₃ · 1H₂O

A 4.175 gram sample of a certain hydrate of copper (II) sulfate, CuSO4•xH2O, is heated until all the water is driven off. The resulting anhydrous compound weighs 3.120 grams. What is the formula of the hydrate?

• CuSO4•H2O

• CuSO4•3H2O

• CuSO4•6H2O

• CuSO4•4H2O

Tags

NGSS.HS-PS1-1