Grade 7 Chapter 7 Study Guide

Chapter 7 Study Guide

Classes 7A, 7B, 7C, 7D have their test on Thursday February 19th
Class 7E has their test on Friday February 20th.

Key Terms

·         change of state

·         condensation

·         deposition

·         dissolve

·         evaporation (vaporization)

·         freezing (solidification)

·         gas

·         heat

·         heterogeneous

·         homogeneous

·         kinetic energy

·         liquid

·         matter

·         mechanical mixture

·         melting

·         mixture

·         particle

·         particle theory of matter

·         pure substance

·         solid

·         solidification

·         solution

·         sublimation

·         temperature

Please review the following:

1. Classifying mixtures: pure substances and mixtures, heterogeneous and homogeneous mixtures, provide examples of these substances
2. Review the "pure substances: worksheet in the package
3. The changes of state and the diagram in the package; review which changes of state require heat and which require heat to be removed to occur
4. Understand how and why substances change state according the the particle theory
5. The difference between heat and temperature
6. Review the motion and behaviour of particles in solids liquids and gases

More Videos About the Particle Theory (viewed in class)

Measuring Temperature




Evaporation and Condensation

Growth Mindset Videos

Your Brain is Plastic (SciShow)




Neuroplasticity (Sentis)

Pure Substances and Mixtures Information Video

Answers to Pure Substances Worksheet

Pure Substances

1. A pure substance and a mixture could be confused because they are both homogeneous in appearance.

2. They are both the same because they are made of the same particles. Many factors can be tested but their results will always behave the same no matter where they come from.

3. b) Jewelry is not pure gold because pure gold is a very soft. The necklaces the can be bought at a store are a mixture of gold and something else to make it stronger (an alloy). Karats are a measure of the purity of the gold; 24 karats is the highest purity for jewelry.

4. If the shirt has a label with 100% cotton then this is not a pure substance because there will be dyes and other materials (logo design materials) that make up the shirt. 

Section 7.1 Notes

Classification of Matter by Composition

Matter – anything that has mass and takes up space

Mass – the amount of matter in the object (grams, Kg)

Volume - the amount of space that matter occupies (m³, mL)

Solid - matter that has a definite shape and volume.

Particles are vibrating in place, but they cannot move freely.

Liquid – matter that does not have a definite shape but does have a definite volume; a liquid takes the shape of its container.

Particles can move freely past each other, however, they remain in a fixed volume.

A gas is matter that does not have a definite shape or volume.

Gas particles can move freely and fill the spaces they are in.

Pure substance – a substance made up of only one type of matter; e.g., sugar, distilled water, copper wire are all pure substances. Pure substances appear uniform or homogeneous; this means that every part of the substance has the same composition as every other part.

Mixture – a substance made up of two or more different substances; e.g., pizza, soft drinks, eggs. Each substance inside the mixture keeps its own properties; e.g., you can’t see the sugar in soft drinks, but you can taste it.

Classifying Mixtures – mixtures can be grouped into 2 major categories; mechanical mixtures and solutions.

Mechanical mixtures – the different parts of the mixture can be seen; the mixture does not have the same properties throughout.

Sometimes, it’s easy to see the different types of matter throughout the mixture; e.g., snack mix; sometimes you need a microscope.

These mixtures are said to be heterogeneous, this means that it is made up of different substances with different appearances and properties.

Solutions – these mixtures have the same appearance throughout, but they are made up of two or more substances. Solutions are made when you dissolve one substance into another.

All solutions are said to be homogeneous mixtures because they look the same throughout even though they are made up of different substances; e.g., dissolving sugar in tea.

Particle Theory Videos

Particles in Solids





Particles in Liquids