Question

How many kJ are produced when 50.0 g of oxygen reacts with excess H2(g) in the following reaction?2H2(g) + O2(g) → 2H2011) + 572 kJYour Answer:

Answer 1

we are given the equation

2H₂(g) + O₂(g) → 2H₂011) + 572 kJ

and we are required to find the amount of KJ produced when 50 g of oxygen are reacted with excess hydrogen

solution

50 grams of oxygen has :

Mols = m/M

= 50/16.00

= 3.125 mols

from the balance equation we see that when 1 mol of oxygen reacts with 2 mols of Hydrogen +572KJ of energy are produces. therefore when 3.125 mols of oxygen are reacted we get :

3.125 x 572

= 1787 KJ

therefore 1787KJ of energy will be produced