Grade 9 End Of Year

Front 1

what is matter ?

Back 1

Anything that has mass and occupies space

Front 2

Pure matter / substance

Back 2

A substance is said to be pure if it contain only one component.
They are divided into elements and compounds

Front 3

What is an element ?

Back 3

A pure substance that is made of the same type of atoms
Example: carbon, oxygen, nitrogen

Front 4

What is a compound ?

Back 4

A pure substances which is formed when the atoms of two or more elements combine chemically.
Example: H2o -> Hydrogen

-> Oxygen

Front 5

Heating Curves

Back 5

A Heating curve is obtained by heating a pure substances and measuring the change in temperature over time

Front 6

What is a atom ?

Back 6

The smallest particle in which an element can exist with losing properties of that element

Front 7

Sub-atomic particles

They are :
- Protons
- Electrons
- Neutrons

Back 7

-The atoms has a central nucleus that contain protons and neutrons

- Outside the nucleus are the electrons that re arranged in energy levels or shells

- Protons: positively charged, electrons: Negatively charged , Neutrons: No charge

Front 8

All compounds are made up of molecules

Back 8

pure substances have a fixed or constant boiling and melting point

Front 9

Impure substances

Back 9

A substance is said to be impure if it contains more than one components.

They are also called mixtures

Example: soda, ice-cream, soup

Front 10

You can know if a substances is pure or impure by measuring it melting or boiling point.

Back 10

Impure substances boil over a narrow range of temperatures.

Front 11

Atomic number = number of protons = number of electrons

Mass number = number of protons + number of neutrons

Number of neutrons = mass number - number of protons

Back 11

Arrangement of electrons in atoms
1st shell - 2 electrons

2nd shell - 8 electrons

3rd shell - 8 electrons

Front 12

What is electronic configuration ?

Back 12

The arrangement of electrons on the shell of the atoms

Front 13

How to determine if a liquid is pure or impure

Back 13

Heat both liquids and measure the boiling point with a thermometer. If the liquid is pure it would boil at a fixed temperature and if the liquid is impure it would boil over a narrow range of temperatures.

Front 14

Change of state

solid - liquid = melting

gas - liquid = condensation

liquid - gas = evaporation

liquid - solid = freezing

gas - solid = sublimation

Back 14

Examples of solids that undergo sublimation

- dry ice

- camphor balls

- Iodine ( purple)

Front 15

Difference between boiling and evaporation

Back 15

- evaporation occurs on the surface of liquids while boiling occurs through out the liquid

- evaporation occurs at any temperature while boiling occurs at a fixed temperature

Front 16

-Elements are arranged in order of their increasing atomic number in the periodic table
- elements can be classified as metals or non- metals

- for the first 20 elements, those whose name end with ' ium ' except helium are metals.

They are: lithium , beryllium, sodium , calcium, magnesium, potassium and aluminium.

Back 16

Compounds in living systems

some compounds are common in both plants and animals. they include:

carbohydrates- they contain the elements carbon, hydrogen, oxygen

examples : glucose , sucrose and starch

primary functions : Provide energy
other functions:acts as a storage material in plants and animals