Chapter 10, Problem 184A

What is the formula and name of a hydrate that is 85.3% barium chloride and 14.7% water?

Interpretation Introduction

Interpretation:

Formula and name of the compound must be determined which is 85.3 % BaCl₂ and 14.7 % H₂O.

Concept introduction:

Percentage mass of an entity in a compound can be calculated as follows:

$\%m\text{=}\frac{\text{Molar mass of the entity}}{\text{Molar mass of the compound}}\times 100\%$

Answer to Problem 184A

Formula of the hydrate is BaCl₂.2H₂O. Name of the hydrate is barium chloride dehydrate.

Explanation of Solution

Molar mass of BaCl₂ is 208 g/mol.

Molar mass of H₂O is 18 g/mol.

85.3% BaCl₂ means 85.3 g BaCl₂ combines with 14.7 g H₂O.

The number of moles of BaCl₂ and H₂O can be calculated as follows:

$n=\frac{m}{M}$

Putting the values,

Mole of BaCl₂$=\frac{85.3\text{ g}}{208\text{ g/mol}}=0.41\text{ mol}$

Mole of H₂O $=\frac{14.7\text{ g}}{18\text{ g/mol}}=0.82\text{ mol}$

Mole ratio of BaCl₂: H₂O $=0.41:0.82=1:2.$

So the formula is BaCl₂.2H₂O.

Conclusion

Formula of the given hydrate is BaCl₂.2H₂O and it is called barium chloride dehydrate.