Lesson 5B Hydrates and Empirical Formulas

A compound is a hydrate when it...

• is composed of only hydrogen and oxygen
• is a state of water
• traps water inside of the compound
• repels water from the compound

Dried or without water

• anhydrate/anhydride

• hydrate

• grapes

Na₂CO₃ · 10H₂O is known as sodium sulfate ______

• Hydroxide
• Hydrate
• Decahydrate
• None of the above

Name the following ionic compound: MgSO₄^.7H₂O

• magnesium sulfate 7-hydrate

• magnesium sulfate hexahydrate

• magnesium sulfate heptahydrate

Name the following hydrate:  NaCl ^. 5H₂O

• sodium chloride 
• sodium monochloride pentahydrate
• sodium chloride pentahydrate
• pentahydrate

Name Cr(NO₃)₃ ⋅ 9H₂O

Hint:

Remember that Chromium has numerous charge options.

So you show the charge in your answer

• chromium nitrate nonahydrate

• chromium nitrogen trioxide nonahydrate

• chromium (III) nitrate nonahydrate

• chromium (I) tritrioxide heptahydrate

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

A 5.018 gram sample of a certain hydrate of magnesium sulfate, MgSO₄•xH₂O, is heated until all the water is driven off. The resulting anhydrous compound weighs 2.449 grams. What is the formula of the hydrate?

• MgSO₄•9H₂O

• MgSO₄•8H₂O

• MgSO₄•7H₂O

• MgSO₄•6H₂O

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