Worksheet: Water of Crystallization

In this worksheet, we will practice defining water of crystallization and explaining its effect on the structures, stabilities, and properties of crystals.

Q1:

How many molecules of water are there per unit of aluminum hydroxide in Al(OH)·3HO32?

Q2:

A sample of magnesium sulfate hydrate (MgSO·HO)42𝑥 is heated until its mass remains constant. For every mole of MgSO4, 7 moles of water are liberated. What is the value of 𝑥?

Q3:

A sample of cobalt(II) chloride hydrate (CoCl·HO)22𝑥 is heated until its mass remains constant. For every 1.00 g of cobalt(II) chloride produced, 0.831 g of water is liberated. What is the value of 𝑥, where 𝑥 is an integer?

Q4:

Copper(II) sulfate hydrate has the molecular formula CuSO·HO42𝑥, where 𝑥 is a whole number. A 3.13 g sample of this compound is heated until its mass remains constant at 2.00 g. Calculate the value of 𝑥.

Q5:

The diagram below shows a piece of equipment called a desiccator that is used to keep substances in a dry atmosphere. Why is the bottom of the desiccator lined with anhydrous calcium chloride?

  • ACalcium chloride is very efflorescent and will easily keep the air inside the desiccator moist.
  • BCalcium chloride is very hygroscopic and will easily remove any moisture from the air inside the desiccator.
  • CCalcium chloride is very good at absorbing carbon dioxide from the air inside the desiccator.
  • DCalcium chloride is inert and will not react with the sample in the desiccator.
  • ECalcium chloride ensures the pH is kept neutral.

Q6:

What name is given to a crystal that does not contain any water of crystallization?

  • AInert
  • BDry
  • CHydrated
  • DInsoluble
  • EAnhydrous

Q7:

What name is given to a crystal that contains water of crystallization?

  • AAnhydrous
  • BWet
  • CAqueous
  • DHydrated
  • ESoluble

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.