Revision Of Matter And Classification

Question 1

Brittle def

Answer 1

How easy it is to break

Question 2

Malleable

Answer 2

The material can be bent and hammered into sheets

Question 3

Ductile

Answer 3

The material can be drawn into wire

Question 4

Thermal conductivity

Answer 4

The material can conduct heat

Question 5

Electrical conductivity

Answer 5

Material conducts electricity

Question 6

Lustre

Answer 6

Shine that material has

Question 7

Magnetic

Answer 7

Material can be attracted by a magnet

Question 8

Density

Answer 8

Mass of material per unit volume

Question 9

Sonorous

Answer 9

Material emits ringing sound when struck

Question 10

Melting point

Answer 10

Temperature at which material changes from solid to liquid

Question 11

Boiling point

Answer 11

Temperature at which material changes from liquid to gas

Question 12

Types of mixtures

Answer 12

Homogeneous and heterogeneous

Question 13

Mixture

Answer 13

Two or more substances combined in which the substances retain their own properties
•Substances present in ratio

Question 14

Homogeneous mixture

Answer 14

• Mixture with the same composition throughout

* Usually consists of substances in the same phase

Question 15

Examples of homogenous mixtures

Answer 15

• Saline solution
• Metal alloy
• Water and sugar without crystals at the bottom
• Air

Question 16

Heterogenous mixture

Answer 16

• A mixture without a uniform composition

* Any combination of molecules that do not dissolve in one another

Question 17

Examples of heterogeneous mixtures

Answer 17

• Sand and water
• Oil and water
• Sugar and water with crystals at the bottom
• Salt water

Question 18

Suspension

Answer 18

When a substance does not dissolve but is merely dispersed throughout the solvent or water

Question 19

Emulsion

Answer 19

When you take two or more substances that are immiscible and attempt to mix them

Question 20

Immiscible

Answer 20

When two liquids do not mix

Question 21

Emulsifiers

Answer 21

Substances added to emulsions to stop them from separating into layers

Question 22

Example of emulsion

Answer 22

Mayonnaise as a result of egg yolk in oil

Question 23

Checks for boiling point

Answer 23

• By using boiling points or melting points as a guide

* Chromatography

Question 24

Properties of mixtures

Answer 24

• Impure substance
• Physical combination of two or more substances
• Separated by physical means
• Substances making up mixtures retain their properties

Question 25

Element properties

Answer 25

* Pure substance * Has one atom * Can't be separated * Has own unique properties

Question 26

Compound properties

Answer 26

* Pure substance * Chemical combination of two or more elements * Made by elements in fixed ratios * Can be separated by chemical means * Properties of compounds are different from the properties of elements

Question 27

Solid phase

Answer 27

* Strong forces called crystal lattice * Vibrate in fixed position * Has shape * Has volume * Particles are close to each other

Question 28

Liquid phase

Answer 28

* Weaker forces than solid * Particles move over each other * Takes shape of container * Has own volume * Particles are close together not compressible

Question 29

Gas phase

Answer 29

* No forces * Free to move * No shape, fills container * Has volume of container * Compressible particles,far apart

Question 30

Freezing point

Answer 30

Temperature at which a liquid changes to a solid

Question 31

What happens when a gas vools?

Answer 31

Condenses

Question 32

Evaporation

Answer 32

When the molecules near the surface with more kinetic energy overcome forces of attraction and escape the liquid and turn into water vapour

Question 33

What happens after evaporation

Answer 33

The less energetic particles are left, causing remaining liquid to drop

Question 34

Differences between evaporation and boiling

Answer 34

* Evaporation happens at any temperature and boiling happens at a specific temperature * Evaporation takes place at the surface only but boiling throughout the liquid * Boiling takes place when vapour in bubbles is equal to atmospheric pressure.

Question 35

Sublimation

Answer 35

When a substance goes straight from being a solid to a gas

Question 36

What happens to molecules of the solid phase when heated?

Answer 36

* They vibrate more energetically, increasing their average kinetic energy and thus the temperature rises * While these molecules vibrate forces of attraction build up and therefore when they get close to each other there are forces of repulsion between them