Question

A.) Write the balanced equation for the hydration of CuSO4. Indicate the physical states using the abbreviations (s), (l), or (g) for solid, liquid, or gas, respectively. Use (aq) to indicate the aqueous phase. Indicate appropriate charges on negative and positive ions if they are formed.

Express your answer as a complete chemical equation including all phases. Do not include water in your answer.

B.) A sample solution containing sulfate ions (SO42−) was analyzed and was found to contain 3.5 mol of sulfate ions (SO42−).

Calculate the equivalent of sulfate ions (SO42−) present in the solution.

Answer 1

A. CuSO4 (s) ==>Cu^2+ (aq) + SO4^2- (aq)

A hydration reaction takes place when you dissolve salt in water, in which salt get ionizes to respective aquated ions.

CuSO4 (s) + H2O (l) ==> Cu^2+ (aq) + SO4^2- (aq) + H2O(l)

Remove H2O(l) from both sides,

CuSO4 (s) ==>Cu^2+ (aq) + SO4^2- (aq)

B. Equivalent of sulfate ions = 7.0

Molar mass of sulfate ions (SO4^2-) = 96.06 g/mol

No. of moles of sulfate ions = 3.5 mol

Since each SO4^2- ions contains 2 negative, it can reacts with 2 equivalents of cations

So, mole equivalent of SO4^2- ions = 3.5 mol x 2 = 7.0 mol

another way,

Mass of 3.5 moles of sulfate ions = 3.5 mol x 96.06 g/mol = 336.21 g

Equivalent mass of sulfate ions = Molar mass /2

Equivalent mass of sulfate ions = 96.06/2 = 48.03 gram equivalent

No. of equivalent of sulfate ions in 336.21 g = 336.21 / 48.03 = 7.0