Question

A sample of unknown hydrate, AC-XH20, has a mass of 1.000 g before heating and a

Answer 1

Answer:

The water of crystallization for the formula of the unknown  hydrate is 2.

Explanation:

Mass of an unknown hydrate = 1.000 g

Molar mass of hydrate = 195.5 g/mol

MOles of unknown hydrate =$\frac{1.000 g}{195.5 g/mol}=0.00512 mol$

Mass of hydrate after heating = 0.781 g

Mass of water lost due to heating = x

$1.000 g = 0.781 g + x\\x = 1.000 g - 0.781 g = 0.219 g$

Moles of water lost =$\frac{0.219 g}{18.01528 g/mol}=0.0122 mol$

$AC.xH_2O+Heat\rightarrow AC+xH_2O$

1 Mole of hydrate has x moles of water and 0.00512 moles of hydrate has 0.0122 moles of water then we can write:

$\frac{1 }{x}=\frac{0.00512 }{0.0122 }\\x\approx 2$

The water of crystallization for the formula of the unknown  hydrate is 2.