Chapter 22 - Elements , Compounds And Mixtures

Question 0

What’s an element ??

Answer 0

*An element is a substance which cannot be broken down into simpler substances by chemical means *

Question 1

What’s an atom ??

Answer 1

*An atom is the smallest part of an element that still has properties of that element *

Question 2

How’s a compound formed ??

Answer 2

*A compound is formed when two or more elements combined together chemically *

Question 3

What’s a molecule ??

Answer 3

*A molecule is the smallest part of an element or compound that can exist on its own *

Question 4

What’s a compound ??

Answer 4

*A compound is a completely new substance with its own properties *
It can not be separated its chemically combined

Question 5

What’s a mixture ??

Answer 5

*A mixture consists of two or more different substances mingled together but not chemically combined *
It can be separated

Question 6

The elements that make up compounds are ..

Answer 6

The elements that make up compounds are always present in definite fixed amounts

Question 7

Examples of mixtures

Answer 7

Air - nitrogen,oxygen,carbon dioxide 
Seawater - water,salt
Ink - water,various dyes 
Coke -water,sugar,flavourings, carbon dioxide 
Steel - iron,carbon

Question 8

What’s the difference between mixture and compound ???

Answer 8

Mixture

1. Consists of two or more substances
2. The proportion of each substance in the mixture does not matter
3. The properties are the same as those of the substances used
4. Usually easy to separate

Compound

1. Consists of a single substance
2. The elements in a compound are always in a fixed position
3. The properties are very different to those of the elements used
4. Very difficult to separate

Question 9

What’s a physical change??

Answer 9

It’s when nothing new is made

Like melting ice nothing changes the molecules are the same

Question 10

What’s a chemical change ??

Answer 10

When you make something new that wasn’t there before
A new substance is always formed
Like burning iron and sulphur together to make iron sulphide it’s hard to separate and is a new substance