Question

A hydrate of iron thiocyanate fe(snc)3.mh2o was found to be 19% water find m.

Answer 1

1 answer · Chemistry 

 Best Answer

A hydrate of ferric thiocyanate (Fe(SCN)3 contains 19.0% H20. What is the salt hydrates formula? 

I like to start with 100 grams of the hydrate, so 19.0 grams are water and 81.0 grams are Fe(SCN)3 

The coefficients in the formula are the mole ratio. 

Molar mass of Fe(SCN)3 = 55.8 + 3 * (32.1 + 12.0 + 14) = 230.1 
Moles of Fe(SCN)3 = 81.0 ÷ 230.1 = 0.352 


Moles of H2O = 19.0 ÷ 18 = 1.0556 

Moles of H2O per mole of Fe(SCN)3 = 1.0556 ÷ 0.352 = 3 : 1 
Fe(SCN)3 * 3 H2O

Answer 2

Answer:

The value of m is 3.

Explanation:

Molar mass of hydrate of iron thiocyanate ,M=230 g/mol+m18 g/mol

Percentage of water = 19%

Percentage of water in a hydrated compound:

$\%=\frac{n \text{molar mass of water}}{\text{Molar mass of compound}}\times 100$

n = number of water molecules

$19\%=\frac{m\times 18g/mol}{230 g/mol+m18 g/mol}\times 100$

m = 2.9 ≈ 3

The value of m is 3.