Answer:
Explanation:
From the 1 g sample you have:
0.546 grams of cobalt chloride
1-0.546=0.454 grams of water
Now:
1) The salt
Of the 0.546 g, 0.248 g are cobalt (Mr=58.9) and the rest id Cl (Mr=35.45):
[tex]n_{Co}=\frac{0.248 g}{58.9 g/mol}=4.21*10^{-3}mol[/tex]
[tex]n_{Cl}=\frac{0.298 g}{35.45g/mol}=8.4*10^{-3}mol[/tex]
Dividing:
[tex]\frac{n_{Cl}}{n_{Co}}=\frac{8.4*10^{-3}mol}{4.21*10^{-3}mol}=2[/tex]
So the molecular formula will be:
[tex]CoCl_2[/tex]
2) The water
The water's molecular weight is M=18 :
[tex]n_{w}=\frac{0.454g}{18g/mol}=0.025 mol[/tex]
Bonding with the Co:
[tex]\frac{n_{w}}{n_{Co}}=\frac{0.025mol}{4.21*10^{-3}mol}=6[/tex]
The complete formula of the hydrate:
[tex]CoCl_2*6 H_2O[/tex]
