Question

How many water molecules are in CuBr₂ .4H₂O?
a) 8
b) 12
c) 16
d) 20

Answer 1

There are 4 water molecules in one formula unit of CuBr₂ · 4H₂O.

Step-by-step explanation:

The chemical formula CuBr₂ · 4H₂O denotes copper(II) bromide tetrahydrate, which means there are four water molecules associated with each formula unit of copper(II) bromide. To find how many water molecules are present, one should simply look at the number directly before the H₂O in the chemical formula.

Here, the number 4 indicates the ratio of water molecules to formula units of the inorganic salt. Therefore, there are 4 water molecules in one formula unit of CuBr₂ · 4H₂O.