Question

Consider the reaction below. How much heat is evolved when 186 g oxygen are reacted with excess hydrogen? 2H2(g)+O2(g)⟶2H2O(g) ΔH=−572 kJ

a. - 106 kJ

b. - 3.32 kJ

c. - 98.4 J

d. - 3400 kJ

Answer 1

Moles of oxygen in 186 gm $O_2 = \dfrac{186}{32}=5.8125 moles=n_2$

$\Delta H_{given}=- 572 kJ$

Now the $\Delta H$ is given for one mole of oxygen,

For 5.812 moles of oxygen,the net heat evolved : $=5.8125 \times(-572)=-3324.75kJ$