Question

One mole of hydrogen at 100$^\circ$C is mixed with one mole of oxygen at 10$^\circ$C. What will be the temperature of the mixture ? Mass of one mole of hydrogen = 2 g and that of one mole of oxygen is 32 g

• A. 12.4$^\circ$ C
• B. 22$^\circ$C
• C. 34.8$^\circ$ C
• D. 45$^\circ$C

Answer 1

Answer: (D)

45$^\circ$C

Answer 2

Molar specific heat is same for oxygen as well as hydrogen. Hence 1 $\times$ C $\times$ (100 - $\theta$)= 1 $\times$ C $\times$ ($\theta$ - 10). i.e. 2$\theta \,=\, 90^{\circ}$ and $\theta \,=\, 45^{\circ}$.