The smart way to improve grades

Comprehensive & curriculum aligned

Affordable pricing from £10/month

Thermodynamics

In this worksheet, students study the laws of thermodynamics in chemical reactions. There is also an introduction to the concepts of entropy and enthalpy.

'Thermodynamics' worksheet

Key stage:  KS 4

Curriculum topic:  Chemistry: Structure, Bonding and the Properties of Matter

Curriculum subtopic:  Changes of State of Matter

Difficulty level:  

down

Worksheet Overview

QUESTION 1 of 10

When studying energy transfers in chemical reactions, it is important to remember that it all happens on a small scale, as we say at the atomic level. Atoms and molecules are responsible for the transmission of tiny amounts of energy, but when they come together we have energy flow on a bigger scale. 

Energy moves between systems of different temperature (along a temperature gradient) in such a way that high energy systems give off energy to low energy systems, e.g. hot to cold. When the temperatures become equal there is no transfer. Remember, it's all about balance!

Energy moves by convection, conduction and radiation and when things get hotter, they also get bigger. This is because when atoms gain kinetic energy (energy associated with movement), they move around faster, so they expand. When they lose heat and consequently kinetic energy (i.e. get colder), they contract.

 

A thermodynamic system is one that exchanges energy with the area around it. If the system is 'in equilibrium', it is actually balanced and 'happy' on its own, so it becomes a closed system, i.e. it does not exchange energy.

 

Thermodynamics are 'guided' by a number of laws:

 

Law 0

If two systems are in equilibrium with a third system, then they are in equilibrium with each other.

This means that, for three systems (A, B and C), if A has the same energy as C and B has the same energy as C, then A also has the same energy as B.

 

Law 1

When energy is added to a system, some of it stays in and increases the overall energy and some of it leaves the system, but does work in the area around it. By 'work' we mean that there is an effect in the area around the system. For example, when we heat a pot of water, the energy increases first. Further, some energy is released and heats the air around it.

 

Law 2

No reaction is 100 per cent efficient. Some amount of energy is always lost to heat. Moreover, it is impossible for heat to flow from a cold object to a hot one without work, as this would go against what is natural; heat flowing from hot to cold.

 

Enthalpy is a measure of heat in a system. It depends on the amount of internal energy, the pressure and volume of a system. If you have more of a substance the enthalpy increases.

Entropy is a measure of random activity in a system at a specific time. Increase in temperature results in increase in entropy. Gases have more entropy than liquids and solids. A chemical reaction that produces gases increases the entropy of the system.

At what level does energy transfer occur in chemical reactions?

What brings energy flow on a big scale?

tiny molecules moving rapidly

tiny energy transmissions at an atomic level put together

tiny bits of kinetic energy

What is the direction of energy flow between two systems?

There is no energy flow.

Energy flows from hot to cold.

Energy flows from cold to hot.

What happens to objects when they gain heat?

contract

expand

stay the same

What is a thermodynamic system?

a system that does not interact with its surrounding area

a system that interacts with its surrounding area

a system that does not take part in energy transfers

What happens to a system 'in equilibrium' in terms of energy transfers?

It takes in energy from its surroundings.

It does not take energy from its surroundings nor does it give any energy off.

System X is 'in equilibrium' with system Z. System Y is also 'in equilibrium' with system Z.

State the relationship between systems X and Y according to Law 0 of thermodynamics.

X and Y are not 'in equilibrium'.

X and Y are 'in equilibrium'.

X and Y are independent of each other.

Is this statement true or false?

When energy is added to a system, it all stays in and increases the overall energy.

true

false

Complete this sentence.

For energy to flow from a cold object to a hot one, ______ needs to be done.

What state of matter has more entropy than the others: solid, liquid or gas?

  • Question 1

At what level does energy transfer occur in chemical reactions?

CORRECT ANSWER
atomic
atomic level
the atomic level
EDDIE SAYS
Energy transfer in chemical reactions occurs at an atomic level.
  • Question 2

What brings energy flow on a big scale?

CORRECT ANSWER
tiny energy transmissions at an atomic level put together
EDDIE SAYS
Tiny energy transmissions at an atomic level put together bring about energy flow on a big scale.
  • Question 3

What is the direction of energy flow between two systems?

CORRECT ANSWER
Energy flows from hot to cold.
EDDIE SAYS
Energy flows from a system with high energy levels to a system with low energy levels, i.e. hot to cold.
  • Question 4

What happens to objects when they gain heat?

CORRECT ANSWER
expand
EDDIE SAYS
Objects expand when they gain heat, because the atoms they are made of gain kinetic energy, which makes them move more and faster.
  • Question 5

What is a thermodynamic system?

CORRECT ANSWER
a system that interacts with its surrounding area
EDDIE SAYS
A thermodynamic system interacts with its surrounding area in a way that allows energy transfers to take place.
  • Question 6

What happens to a system 'in equilibrium' in terms of energy transfers?

CORRECT ANSWER
It does not take energy from its surroundings nor does it give any energy off.
EDDIE SAYS
A system 'in equilibrium' does not take energy from its surroundings nor does it give any energy off.
  • Question 7

System X is 'in equilibrium' with system Z. System Y is also 'in equilibrium' with system Z.

State the relationship between systems X and Y according to Law 0 of thermodynamics.

CORRECT ANSWER
X and Y are 'in equilibrium'.
EDDIE SAYS
According to Law 0 of thermodynamics, X and Y are 'in equilibrium'.
  • Question 8

Is this statement true or false?

When energy is added to a system, it all stays in and increases the overall energy.

CORRECT ANSWER
false
EDDIE SAYS
The statement is false. When energy is added to a system, some stays in and increases the overall energy, but some of it leaves the system.
  • Question 9

Complete this sentence.

For energy to flow from a cold object to a hot one, ______ needs to be done.

CORRECT ANSWER
work
EDDIE SAYS
For energy to flow from a cold object to a hot one, work needs to be done.
  • Question 10

What state of matter has more entropy than the others: solid, liquid or gas?

CORRECT ANSWER
gas
EDDIE SAYS
Gases have an increased entropy in relation to liquids and solids.
---- OR ----

Sign up for a £1 trial so you can track and measure your child's progress on this activity.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Start your £1 trial

Start your trial for £1