(A) For an expansion into a vacuum,the external pressure $p_{ex} = 0 \ atm$.The work done in an expansion is given by $w = -p_{ex} \Delta V$.Since $p_

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

(A) For an expansion into a vacuum,the external pressure $p_{ex} = 0 \ atm$.The work done in an expansion is given by $w = -p_{ex} \Delta V$.Since $p_{ex} = 0$,the work done $w = 0 \ L \ atm$.According to the first law of thermodynamics,$\Delta U = q + w$.For an isothermal expansion of an ideal gas,the change in internal energy $\Delta U = 0$.Therefore,$0 = q + 0$,which implies $q = 0$.Thus,no work is done and no heat is absorbed.

Class 11 Chemistry Thermodynamics First law of thermodynamics

Easy

Two litres of an ideal gas at a pressure of $10 \ atm$ expands isothermally at $25^{\circ}C$ into a vacuum until its total volume is $10 \ litres$. How much heat is absorbed and how much work is done in the expansion?

A
$q = 0, w = 0$
B
$q = 80 \ L \ atm, w = -80 \ L \ atm$
C
$q = -80 \ L \ atm, w = 80 \ L \ atm$
D
$q = 0, w = 80 \ L \ atm$

Explore More

Browse All

Question Bank

All Subjects

Class 11 Questions

Class 11

Chemistry Questions

Chapter

Thermodynamics

Subtopic

First law of thermodynamics

Assertion : For an isothermal reversible process $Q = -W$,i.e.,work done by the system equals the heat absorbed by the system.
Reason : Enthalpy change $(\Delta H)$ is zero for an isothermal process.

MediumAIIMS 2011

View Solution

At the $1$ bar pressure,the volume of a gas is $0.6 \ L$. If the gas receives $122 \ J$ of heat at $1$ bar pressure,the volume becomes $2 \ L$. Calculate the change in its internal energy. $(1 \ L \cdot bar = 101.32 \ J)$

Medium

View Solution

For the reaction $C_{(s)} + \frac{1}{2}O_{2(g)} \to CO_{(g)}$ at constant $T$ and $P$,which of the following statements is correct?

Medium

View Solution

At $298 \ K$,what is the value of $\Delta H - \Delta E$ in $J \ mol^{-1}$ when $1 \ mol$ of carbon monoxide gas is formed from its elements in their standard states? $[R = 8.314 \ J \ K^{-1} \ mol^{-1}]$

Medium

View Solution

Assuming all reactions occur in an open vessel,for which reaction will $\Delta H = \Delta U$?

Easy

View Solution

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial

For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free

For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo

Two litres of an ideal gas at a pressure of $10 \ atm$ expands isothermally at $25^{\circ}C$ into a vacuum until its total volume is $10 \ litres$. How much heat is absorbed and how much work is done in the expansion?

Similar Questions

Assertion : For an isothermal reversible process $Q = -W$,i.e.,work done by the system equals the heat absorbed by the system.Reason : Enthalpy change $(\Delta H)$ is zero for an isothermal process.

At the $1$ bar pressure,the volume of a gas is $0.6 \ L$. If the gas receives $122 \ J$ of heat at $1$ bar pressure,the volume becomes $2 \ L$. Calculate the change in its internal energy. $(1 \ L \cdot bar = 101.32 \ J)$

For the reaction $C_{(s)} + \frac{1}{2}O_{2(g)} \to CO_{(g)}$ at constant $T$ and $P$,which of the following statements is correct?

At $298 \ K$,what is the value of $\Delta H - \Delta E$ in $J \ mol^{-1}$ when $1 \ mol$ of carbon monoxide gas is formed from its elements in their standard states? $[R = 8.314 \ J \ K^{-1} \ mol^{-1}]$

Assuming all reactions occur in an open vessel,for which reaction will $\Delta H = \Delta U$?

Vedclass Test Series

Exam Paper Generator

Online Exam Module

Assertion : For an isothermal reversible process $Q = -W$,i.e.,work done by the system equals the heat absorbed by the system.
Reason : Enthalpy change $(\Delta H)$ is zero for an isothermal process.