Question

A 60-gram sample of LiCl · H 2 O is heated in an open crucible until all of the water was driven off. What is the total mass of LiCl remaining in the crucible

Answer 1

42.11 g

Step-by-step explanation:

Mass of the hydrated salt = 60 g

The moles of the hydrated salt is :

Amount = 60 g

Molar mass of
`LiCl.H_2O` = 60.4093 g/mol

The formula for the calculation of moles is shown below:

`moles=\frac {Mass\ taken}{Molar\ mass}`

Thus, moles are:

`moles=(60\ g)/(60.4093\ g/mol)`

`moles= 0.9932\ mol`

After heating only LiCl remains in the crucible. So,

Moles of LiCl = 0.9932 moles

Molar mass of
`LiCl` = 42.394 g/mol

The formula for the calculation of moles is shown below:

`moles = (Mass\ taken)/(Molar\ mass)`

Also, mass is

`Mass=moles* Molar\ mass`

`Mass=0.9932* 42.394`

Total mass of LiCl remaining in the crucible = 42.11 g