ELEMENTS: MIXTURES AND COMPOUNDS

Question 1

What are elements?

Answer 1

The simplest kind of substance

Question 2

Can elements be broken down?

Answer 2

No

Question 3

How many types of atoms do elements contain?

Answer 3

Only one

Question 4

Give 3 examples of elements

Answer 4

Oxygen
Magnesium
Carbon

Question 5

What is a mixture? - 3

Answer 5

Made of 2 or more substances mixed together:

1. And no chemical reaction has taken place
2. The properties of the components of the substance have not changed
3. The components can be separated (as they are not chemically bonded together)

Question 6

What is a compound? - 3

Answer 6

1. Formed when 2 or more substances are mixed AND a chemical reaction takes place
2. The properties of the substance are different from those of the substances that it is made from
3. The constituent parts are very difficult to separate

Question 7

Can you name 4 compounds?

Answer 7

Iron Sulphide
Copper Sulphide
Iron Oxide
Copper Oxide

Question 8

Air is a mixture of? - 6

Answer 8

1. Nitrogen
2. Oxygen
3. Carbon Dioxide
4. Water Vapour
   But these gases stay separate from each other
   They do not react to form new compounds
   NO CW

Question 9

Explain why salt water is a mixture? - 3

Answer 9

1. The salt is dissolved
2. The salt molecules do not chemically combine with the water molecules
3. They just fill up the spaces between the water molecules

Question 10

How can mixtures be separated easily? - 4

Answer 10

By physical methods such as:
1. Filtering 
2. Chromatography
3. Evaporation
4. Distillation  
C FED

Question 11

What happens in a compound? - 3

Answer 11

1. The different substances have been chemically reacted together
2. New molecules have been formed
3. The atoms of different elements in the compound are chemically bonded together

Question 12

A compound has different physical and chemical properties from the elements it contains, give an example

Answer 12

Copper sulphate - contains copper, sulphur, oxygen

Question 13

How many elements do compounds ending in ‘ate’ contain?

Answer 13

3 or more, one of which must be OXYGEN

Question 14

How can compounds be separated into their different elements?

Answer 14

By using chemical reactions because their elements have been chemically bonded together

Question 15

What is a thermal decomposition reaction?

Answer 15

When a compound breaks down as a result of being heated