Heat, Work and the First Law

Name: Heat, Work and the First Law
Author: StemPy Lab

When you pump a bicycle tyre, the pump becomes warm, and nobody heated it. In this course we define the internal energy of a gas, we separate heat from work, and we find the work as the area under a pressure-volume graph. Then we write the first law of thermodynamics, which is the law of conservation of energy for heat and work.

3 lessons, about 1 h 15 min3 simulations12 problems6 practice questionsPython in every lesson

Created by StemPy Lab

Course outline (3 lessons)

Lesson 1about 25 min
Thermal equilibrium, internal energy, heat and work
Bodies in contact reach thermal equilibrium at one temperature (the zeroth law). A body's internal energy is the energy of its molecules; for an ideal gas it depends only on temperature, $U = \tfrac{f}{2}nRT$ . Heat and work are two ways of passing energy to or from a body: heat because of a temperature difference, work by a force moving something.
1 simulation2 practice questions1 Python program4 problems
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Lesson 2about 25 min
The first law of thermodynamics
The first law of thermodynamics is the conservation of energy: $\Delta U = Q - W$ , where $Q$ is the heat taken in and $W$ the work done by the system. Heat and work depend on the path, but their difference, the change of internal energy, depends only on the starting and final states.
1 simulation2 practice questions1 Python program4 problems1 Python lab
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Lesson 3about 25 min
Work done by a gas and the p-V diagram
A gas that expands does work $W = \int p\,dV$ , the area under its path on a pressure-volume graph. At a steady pressure $W = p\,\Delta V$ ; at a steady temperature $W = nRT\ln\dfrac{V_2}{V_1}$ . Different paths between the same states give different work, and a cycle's net work is the area it encloses.
1 simulation2 practice questions1 Python program4 problems1 Python lab1 question set1 note
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Heat, Work and the First Law: Practice Paper

15 questions · 20 min

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Heat, Work and the First Law

Course outline (3 lessons)

Thermal equilibrium, internal energy, heat and work

The first law of thermodynamics

Work done by a gas and the p-V diagram

Test Your Learning

Your teacher

Discussion (0)