Problem 1

An amount of 20 g of potassium sulphate was dissolved in 150 cm

^3

of water. The solution was then electrolysed. After electrolysis, the content of potassium sulphate in the solution was 15 % by mass. What volumes of hydrogen and oxygen were obtained at a temperature of 20 °C and a pressure of 101 325 Pa?

Step 2 of 3: Moles of gases

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n(\ce{H2}) = 2.04\ \text{mol}, \quad n(\ce{O2}) = 1.02\ \text{mol}

Analysis

From $\ce{2H2O -> 2H2 + O2}$ , the water decomposed gives the same moles of H2 and half as many moles of O2.