NS Part 1 G8 Caps

How do particles behave in a solid?

They vibrate in fixed positions, giving solids a definite shape.

How do particles behave in a liquid?

They are close together but can slide past each other, giving liquids fixed volume but no fixed shape.

How do particles behave in a gas?

They are far apart and move rapidly, allowing gases to fill any space.

What happens to particles during a change of state?

Their energy changes, but the particles themselves stay the same.

What effect does heating have on particles?

It increases their movement and energy.

What effect does cooling have on particles?

It slows their movement.

Why does diffusion happen?

Because particles are constantly moving from high to low concentration.

What is an atom?

The basic building block of matter.

What is an element?

A pure substance made of only one type of atom.

What is a molecule?

Two or more atoms chemically bonded together.

What is a compound?

A substance formed when atoms of different elements join chemically.

Why do compounds have different properties from the elements that form them?

Because chemical bonding creates new substances with new properties.

What does the periodic table show?

Elements arranged by atomic structure and chemical behaviour.

What are typical properties of metals?

Shiny, conductive and malleable.

What are typical properties of non-metals?

Dull, brittle when solid, and poor conductors.

What is a chemical reaction?

A process where substances interact to form new substances.

What is a reactant?

A starting substance in a chemical reaction.

What is a product?

A new substance formed during a chemical reaction.

What shows that a chemical reaction has occurred?

Colour change, heat change, gas formation or solid formation.

Why is mass conserved in a chemical reaction?

Because atoms rearrange but are not created or destroyed.

What is combustion?

A reaction with oxygen that releases heat and light.

What is rusting?

A reaction between iron, oxygen and water forming iron oxide.

What is decomposition?

A reaction where one compound breaks into simpler substances.

What is neutralisation?

A reaction between an acid and a base.

What is an exothermic reaction?

A reaction that releases energy.

What is an endothermic reaction?

A reaction that absorbs energy.

What determines a material's uses?

Its physical and chemical properties.

Why are metals used for pots and wiring?

Because they conduct heat and electricity well.

Why are plastics used for packaging?

They are durable, lightweight and corrosion-resistant.

Why are ceramics used for tiles and bricks?

They are heat-resistant and strong under compression.

What is density?

The mass per unit volume of a material.

What is the basic unit of life?

The cell.

What structures do plant and animal cells share?

Cell membrane, cytoplasm and nucleus.

What does the cell membrane do?

Controls entry and exit of substances.

What does the cytoplasm do?

Contains organelles and is where many reactions occur.

What does the nucleus do?

Controls cell activities.

What structures are unique to plant cells?

Cell wall, chloroplasts and a large vacuole.

What is the function of chloroplasts?

To carry out photosynthesis.

What is mitosis?

Cell division for growth and repair.

What is the role of the digestive system?

To break down food for absorption.

What is the role of the respiratory system?

To exchange oxygen and carbon dioxide.

What is the role of the circulatory system?

To transport nutrients, gases and wastes.

What is the role of the excretory system?

To remove waste products.

What is the role of the nervous system?

To detect stimuli and coordinate responses.

What is the function of the cornea?

To begin focusing light entering the eye.

What controls the size of the pupil?

The iris.