F2 - SEM1 - Living things and air - 7.1

Question 1

Air is a ____ of gases.

7.1 Air

Answer 1

Air is a mixture of gases

7.1 Air

Question 2

What are the components of air?

7.1 Air

Answer 2

• 78% nitrogen
• 21% oxygen
• 0.04% carbon dioxide
• 0.9% noble gases ( a group of unreactive gases)
• water vapour
• other gases

7.1 Air

Question 3

How to test for oxygen?

7.1 Air

Answer 3

It relightens a glowing splint

7.1 Air

Question 4

How to test for carbon dioxide?

7.1 Air

Answer 4

• turns hydrogencarbonate indicator from red to yellow
• turns lime water from colourless to milky

7.1 Air

Question 5

How to test for Nitrogen?

7.1 Air

Answer 5

No simple test for nitrogen

7.1 Air

Question 6

How to test for water?

7.1 Air

Answer 6

turns dry cobalt chloride paper from blue to pink

7.1 Air

Question 7

Why you should not touch dry cobalt chloride paper with your hands?

7.1 Air

Answer 7

The moisture on your hands will change the colour of the paper

7.1 Air

Question 8

Where do we keep the dry cobalt chloride paper?

7.1 Air

Answer 8

desiccator

7.1 Air

Question 9

What are the properties of Oxygen?

7.1 Air

Answer 9

• Colourless, Odourless
• Supports burning

7.1 Air

Question 10

What are the properties of Carbon dioxide?

7.1 Air

Answer 10

• Colourless, Odourless
• Does not support burning
• Denser than air
• Changes from solid (dry ice) to gas directly at -78C

7.1 Air

Question 11

What are the properties of Nitrogen?

7.1 Air

Answer 11

• Colourless, Odourless
• Unreactive
• Very low boiling point at -196C

7.1 Air

Question 12

What are the uses of Oxygen?

7.1 Air

Answer 12

• Mixed with a fuel gases to produce a flame for cutting and welding metals
• Air with high oxygen content can be used to help patient with breathing difficulties

7.1 Air

Question 13

What are the uses of Carbon dioxide?

7.1 Air

Answer 13

• Used in some fire extinguishers
• Used in stage shows to produce the effect of dense fog

7.1 Air

Question 14

What are the uses of Nitrogen?

7.1 Air

Answer 14

• Used in food packaging
• Used in the storage of living cells

7.1 Air

Question 15

What is Noble gases?

7.1 Air

Answer 15

A group of unreactive gases

7.1 Air

Question 16

Give two examples of noble gases

7.1 Air

Answer 16

• Helium
• Neon

7.1 Air

Question 17

What are properties and uses of Helium?

7.1 Air

Answer 17

• Properties: less dense than air
• Uses: balloons filled with helium float in air

7.1 Air

Question 18

What are properties and uses of Neon?

7.1 Air

Answer 18

Properties: glows when electricity passes through it
Uses: often used to fill neon signs

7.1 Air

Question 19

True of False?

Glucose produced in plants can be stored as starch for later use

7.1 Air

Answer 19

True

7.1 Air

Question 20

True or False?

A burning splint burns more brightly in carbon dioxide

7.1 Air

Answer 20

False

A burning splint burns brightly in oxygen

7.1 Air

Question 21

True of False?

If a burning splint goes out quickly in a gas, the gas must be carbon dioxide

7.1 Air

Answer 21

False

Both carbon dioxide and nitrogen can

7.1 Air

Question 22

True or False?

Nitrogen can be used fill in packages of potato chips to keep the potato chips longer

7.1 Air

Answer 22

True

7.1 Air

Question 23

True or False?

Carbon dioxide can be used to produce a flame of very high temperature for welding metals

7.1 Air

Answer 23

False

Oxygen mixed with fuel gas to produce a flame of very high temperature

7.1 Air

Question 24

True or False?

Solid nitrogen is common known as dry ice

7.1 Air

Answer 24

False

7.1 Air

Question 24

True or False?

Solid carbon dioxide is common known as dry ice

7.1 Air

Answer 24

True

7.1 Air

Question 25

Suggest one daily use of the gas which turns the hydogencarbonate indicator yellow

7.1 Air

Answer 25

It can put out fire

Carbon dioxide

7.1

Question 26

True or False?

The percentages of different gases in the air are fixed

7.1 Air

Answer 26

False

7.1 Air