When hydrochloric acid is poured over potassium sulfide, 43.7 mLmL of hydrogen sulfide gas is produced at a pressure of 758 torrtorr and 26.0 ∘C?

0.196 grams of K2S reacted

Explanation:

When hydrochloric acid is poured over potassium sulfide, 43.7 mLmL of hydrogen sulfide gas is produced at a pressure of 758 torrtorr and 26.0 ∘C

How much potassium sulfide has reacted in grams?

Step 1: Data given

Volume of hydrogen sulfide (H2S) produced = 43.7 mL

Pressure = 758 torr = 758/760 = 0.9973684 atm

Temperature = 26.0 °C = 273 + 26 = 299 K

Step 2: The balanced equation

2 HCl + K2S → H2S + 2 KCl

Step 3: Calculate moles H2S

p*V = nRT

n = (pV) / (RT)

⇒ with n = the number of moles of H2S

⇒ with p = the pressure = 0.9973684 atm

⇒ with V = the volume of the gas = 43.7 mL = 0.0437 L

⇒ with R = the gas constant = 0.08206 L*atm/K*mol

⇒ with T = The temperature = 26°C = 299 Kelvin

n = (0.9973684 * 0.0437) / (0.08206*299)

n = 0.001776 moles H2S

Step 4: calculate moles of K2S

For 2 moles HCl we need 1 mol K2S to produce 1 mol H2S and 2 moles KCl

For 0.001776 moles H2S produced, we need 0.001776 moles K2S

Step 5: Calculate mass of K2S

Mass K2S = moles K2S * molar mass K2S

Mass K2S = 0.001776 moles * 110.26 g/mol

Mass K2S = 0.196 grams K2S

0.196 grams of K2S reacted