Calculate the mass of a substance that is formed by the interaction of 39 grams of potassium with sulfur.

| July 8, 2021 | education

1.Calculate the amount of potassium substance according to the formula:

n = m: M, where M is molar mass.

M (K) = 39 g / mol.

n = 39: 39 g / mol = 1 mol.

2. Let’s compose the equation of the reaction between potassium and sulfur:

2K + S = K2S.

According to the reaction equation, for 2 mol of potassium there is 1 mol of potassium sulfide, that is, the substances are in quantitative ratios of 2: 1, which means that the amount of potassium sulfide substance will be 2 times less than the amount of potassium sulfide.

n (K2S) = 1: 2 = 0.5 mol.

Or:

2 mol K – 1 mol K2S.

1 mol Al – n mol K2S.

n mol = (1 mol × 1 mol): 2 = 0.5 mol.

3. Calculate the mass of potassium sulfide by the formula: m = n M,

M (K2S) = 39 × 2 + 32 = 110 g / mol.

m = 110 g / mol × 0.5 mol = 55 g.

Answer: m = 55 g.



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