To a solution containing 39 g of sodium sulfide was added a solution containing 80 g
To a solution containing 39 g of sodium sulfide was added a solution containing 80 g of zinc chloride. Calculate the mass of the precipitate formed.
Find the amount of sodium sulfide Na2S by the formula:
n = m: M.
M (Na2S) = 78 g / mol.
n = 39 g: 78 g / mol = 0.5 mol.
M (ZnCl2) = 136 g / mol.
n = 80: 136 = 0.588 mol.
Let’s compose the reaction equation, find the quantitative ratios of substances.
Na2S + ZnCl2 = ZnS ↓ + 2NaCl.
Na2S is given in deficiency.
According to the reaction equation, there is 1 mole of ZnS per 1 mole of Na2S.
The substances are in quantitative ratios of 1: 1.
The amount of substance will be equal.
n (ZnS) = n (ZnCl2) = 1: 1 = 0.5 mol.
Find the mass of ZnCl2
M (ZnS) = 97 g / mol.
m = n × M.
m = 97 g / mol × 0.5 mol = 48.5 g.
Answer: 48.5 g.