1)

One of the hydrates of CoCl₂is cobalt(II) chloride dihydrate. A 81.8 gram sample of CoCl₂ 2 H₂O was heated thoroughly in a porcelain crucible, until its weight remained constant. After heating, how many grams of the anhydrous compound remained?

2)

A student is running an experiment in which 34.3 grams of KF is needed, but the only jar of reagent in the lab is labelled potassium fluoride dihydrate. How many grams of the hydrate must the student weigh out in order to get the desired amount of the anhydrous compound?

3)

One of the hydrates of CoSO₄is cobalt(II) sulfate hexahydrate. A 66.4 gram sample of CoSO₄ 6 H₂O was heated thoroughly in a porcelain crucible, until its weight remained constant. After heating, how many grams of the anhydrous compound remained?

4)

What is the mass of a boron tribromide molecule ?
grams?

5)

What is the mass of a nitrogen dioxide molecule ?
grams?

6)

How many grams of S are present in 3.36 grams of disulfur decafluoride ?
grams S.


7)

How many grams of disulfur decafluoride contain 1.48 grams of F ?
grams disulfur decafluoride.

8)

How many grams of Ca²⁺ are present in 4.09 grams of calcium bromide?
grams Ca²⁺.

9)

How many grams of calcium bromide contain 3.87 grams of Ca²⁺?
grams calcium bromide.

10)

How many grams of Fe²⁺ are present in 1.16 grams of iron(II) cyanide?
grams Fe²⁺.

11)

How many grams of iron(II) cyanide contain 3.07 grams of Fe²⁺?
grams iron(II) cyanide.