NS Term 2

Question 1

Describe the particles in a solid object:

Answer 1

• Packed tightly together
• Very small space between particles
• Particles vibrate in one place
• Particles have little energy of motion

Question 2

Describe the particles of a liquid object:

Answer 2

• Particles have no fixed pattern
• Spaces between particles are small
• Particles move around and glide over each other
• Particles have more energy of motion than in solids

Question 3

Describe the particles of a gas object:

Answer 3

• There is no order for particles to move in
• The spaces between the particles are large
• Particles move very fast and freely in all directions
• Particles have lots of energy of motion

Question 4

What two changes of state are needed for a solid to change into a gas?

Answer 4

solid (melting) > liquid (evaporation) > gas

Question 5

What two changes of state need to happen for a gas to become a solid?

Answer 5

gas (condensation) > liquid (freezing/crystallising) > solid

Question 6

What happens when particles are heated?

Answer 6

They gain energy of motion and change state (Eg: melting)

Question 7

What is another name for energy of motion?

Answer 7

Kinetic energy

Question 8

What happens when particles are cooled?

Answer 8

They lose kinetic energy and change state (Eg: condensation)

Question 9

What is a mixture?

Answer 9

Two or more substances with different properties that are mixed together

Question 10

Do the substances in mixtures react chemically?

Answer 10

No they don’t

Question 11

What are some ways mixtures can be seperated? (Study page 214 further)

Answer 11

• Hand sorting
• Sifting
• Seperating funnel
• Filtration
• Magnetism
• Evaporation

Question 12

What is a “solution”? (In terms of mixtures)

Answer 12

When two substances are mixed and form a new substance
(Eg: Water + Coffee grounds = Coffee)
In this case; coffee grounds = soluble substance / water = solvent

Question 13

What are substances that cannot dissolve in water called?

Answer 13

Insoluble solids

Question 14

What is a solution of metals called?

Answer 14

An alloy

Question 15

What is a “Saturated Solution?”

Answer 15

When no more of the solute can dissolve in the solvent at a specific temperature

Question 16

What is the point called where no more solute can be dissolved?

Answer 16

The saturation point

Question 17

What is “Crystallisation?”

Answer 17

When crystals form from a solution

Question 18

What are the three factors that affect the rate of dissolving?

Answer 18

• Temperature
• Stirring or shaking the mixture
• Grain size of the solute

Question 19

What is water pollution?

Answer 19

When water resources are contaminated and dirty

Question 20

How are some ways water can be polluted?

Answer 20

Soluble substances (like chemicals)
Insoluble substances (like litter and waste)
Living germs (like bacteria)

Question 21

What are some causes of water pollution? (Study page 262 for more info)

Answer 21

Sewage
Industries and mines
Oil
Litter
Agriculture

Question 22

What effects do water pollution have?

Answer 22

A negative affect on sealife and coastlines
Poisoning wildlife
Causes waterborne disease
Leads to death of wildlife and humans

Question 23

What is a natural solution to water pollution?

Answer 23

Wetlands

Question 24

What are wetlands important for?

Answer 24

The removal of waste from water
The regulation of flow of water

Question 25

What happens when wetlands are destroyed

Answer 25

Habitats of birds and fish are destroyed
Natural pollutant filters are destroyed
Natural dams and marshes are destroyed

Question 26

What is the importance of clean water?

Answer 26

Humans need it for cooking, cleaning and washing
Animals need water for cooling, hydration and their habitat
Plants need water for growth

Question 27

What are the standards for water mandated by the government?

Answer 27

Must comply with standards for clean water
Must be affordable
Supply must be consistent and sustainable

Question 28

What are methods for cleaning water? (see page 282 for more)

Answer 28

Sifting
Settling
Decanting
Filtration
Boiling
Addition of chemicals