A8.85 g sample of hydrate of sodium carbonate, na, co, xh, o was heated carefully until no more mass was lost from the sample after heating, the final weight of the material was 7.55 g what is the sodium carbonate (na,-water mole ratio?
a) 1: 0
b) 1: 1
c) 2: 1
d) 1: 2

b) 1:1

Explanation:

Mass of the hydrated salt = 8.85 g

Mass of the dehydrated salt = 7.55 g

Mass of water lost = 8.85 - 7.55 g = 1.3 g

The moles of the dehydrated salt is :

Amount = 7.55 g

Molar mass of = 105.9888 g/mol

The formula for the calculation of moles is shown below:

Thus, moles are:

The moles of water is :

Amount = 1.3 g

Molar mass of = 18 g/mol

The formula for the calculation of moles is shown below:

Thus, moles are:

The simplest ration of the two are:

= 0.07123 : 0.0722 = 1 : 1