Answer to Question #112658 in General Chemistry for Matias

Question

When heated, KClO3 solid forms solid KCl and O2 gas. A sample of KClO3 is heated and 185 mL of gas with a pressure of 775 mmHg is collected over water, at 26 ∘C. At 26 ∘C, the vapor pressure of water is 25 mmHg: 2(KClO3)(s)→2(KCl)(s)+3(O2)(g)

Answer 1

p₁ = 185 mL

V₁ = 775 mmHg

p₂ = 25 mmHg

V₂ -?

Solution:

2KClO₃(s)→2KCl(s)+3O₂(g)

 At a constant temperature and constant values of the gas mass and its molar mass, the product of the gas volume and its pressure remains constant: pV = const

p₁ *V₁ = p₂*V₂

V₂ = p₁*V₁/p₂

V₂ = 775 mmHg* 185 mL/25 mmHg = 5735 mL =5.735 L

Answer: 5.735 L