Embibe Experts Solutions for Chapter: Chemical Thermodynamics and Energetics, Exercise 1: Maharashtra Board-2018

State and explain Hess’s law of constant heat summation.

5 moles of helium expand isothermally and reversibly from a pressure $40\times {10}^{-5 } {\mathrm{Nm}}^{-2 } \mathrm{to} 4\times {10}^{-5 } {\mathrm{Nm}}^{-2 }$ at 300 K. Calculate the work done, change in internal energy and heat absorbed during the expansion. $(\mathrm{R}=8.314 {\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1})$

A system absorbs $6 \mathrm{kJ}$ of heat and does $1.5 \mathrm{kJ}$ of work on its surroundings. The change in internal energy is _____.

Write the conditions for maximum work done by the system.

Calculate the work done in the following reaction at $50°\mathrm{C}$. State whether work is done on the system or by the system.

${\mathrm{SO}}_{2\left(\mathrm{g}\right)}+\frac{1}{2}{\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{SO}}_{3\left(\mathrm{g}\right)}$

The standard enthalpy of combustion of formaldehyde is ${∆}_{\mathrm{c}}\mathrm{H}°=-517 \mathrm{kJ}$. How much heat will be evolved in the formation of $22 \mathrm{g}$ of ${\mathrm{CO}}_2$?

Define:
Reversible process

Standard enthalpy of combustion
Calculate the enthalpy change for the reaction:
${{\mathrm{N}}_2}_{\left(\mathrm{g}\right)}+3{\mathrm{H}}_{2\left(\mathrm{g}\right)}\to 2{\mathrm{NH}}_{3\left(\mathrm{g}\right)}$
The bond enthalpies are: