Answer to Question #250234 in General Chemistry for Paulo Kunjo

Question

Pentane is burnt with 96000 cm3 of oxygen gas at room temperature and pressure.
Calculate the mass of zinc needed to react with 50 cm3 of 0.8 M of Hydrochloric acid.

Answer 1

96000 cm³ of oxygen is $\frac{96000}{1000\times22.4}=4.29$ mol of oxygen

The reaction between pentane and oxygen is:

C₅H₁₂ + 8O₂ = 5CO₂ + 6H₂O

50 cm³ of 0.8 M HCl contains $\frac{50\times0.8}{1000} = 0.04 \ mol$ of HCl

The equotion between Zn and HCl:

Zn + 2HCl = ZnCl₂ + H₂

The mass of zink needed is $\frac{0.04\times65.38}{2} = 1.3076$ g