Question

When hydrochloric acid is poured over potassium sulfide, 292.4 mL of the product, H2S, is obtained at a pressure of 709 torr and a temperature of 35.6°C. How many grams of potassium sulfide reacted with the excess hydrochloric acid? The unbalanced chemical equation is:

HCl(aq) + K2S(s) → H2S(g) + KCl(aq)

Answer 1

The number of grams of potassium sulfide reacted with hydrochloric acid is 3.54 g

Step-by-step explanation:

To determine the number of grams of potassium sulfide reacted with the excess hydrochloric acid, we need to use stoichiometry. First, we need to calculate the number of moles of hydrogen sulfide produced using the ideal gas law:

n = (PV) / (RT) = (0.709 atm * 292.4 mL) / (0.0821 L * mol^(-1) * K^(-1) * 308.75 K) = 0.032 mol

Therefore, the number of moles of K2S reacted is also 0.032 mol since the stoichiometric ratio of H2S to K2S is 1:1. To calculate the mass of K2S, we need to use the molar mass of K2S:

m = n * M = 0.032 mol * 110.3 g * mol^(-1) = 3.54 g