Concept Card - Air

We need Oxygen to breathe so I think Air is Oxygen

I think Air is a mixture of gases

THINK, PAIR SHARE ….What do you think?

Gases in the Air

Q4. Draw a bar graph to show the composition of gases in the air.

Q1. What % of the air is oxygen?

Q2. What % of the air is nitrogen?Q3. What % of the air is carbon dioxide?

Testing for Gases

Collect a test tube and add a tiny amount of MnO2 and then 5 ml of H2O2. O2 is produced.

Have a glowing splint near the mouth of the test tube and remove the stopper.

Carefully place the glowing splint inside the tube, without touching the test tube sides.

Oxygen Gas

What happened to the glowing splint?

Canon Fire

Your teacher will demonstrate an experiment which shows howoxygen increases the rate of burning.

Ethanol and hydrogen peroxide are placed in an evaporatingbasin and set alight. Potassium permanganate is thrown onto theflames. Everyone must be at a safe distance behind the safety screen as the mixture will spit out.

Testing for Gases

Hydrogen Gas

You are now going to make hydrogen gas.

• Place 10 cm3 of Nitric Acid in a test tube.

• Add a few pieces of magnesium shavings.

• Carefully place a burning splint over the mouth of the test tube.

What happened to the burning splint?

zinc

Hydrogen Rocket

A bottle containing hydrogen and oxygen gas is set up

As shown below:

A burning splint, on the end of a metre stick is placed directly under the mouth of the bottle. All pupils should be at the back of the room. Ensure that the bottle is upright and not tilted towards the pupils at the back of the room.

Testing for Gases

Carbon Dioxide GasYou are now going to make carbon dioxide gas. Set up the apparatus shown below. Add 10 cm3 of acid to theconical flask and add chalk chips. The carbon dioxide Produced will be bubbled through the lime water.

acid + marble chips

What happened to the lime water?

Nitric Acid + Chalk Lime water

Carbon Dioxide Gas

Lake Nyos Disaster

Nyos is a deep lake high on the flank of an inactive

Volcano in Cameroon. A pocket of magma lies beneath

the lake and leaks carbon dioxide into water. On August

21, 1986 Nyos emitted a large cloud of CO2, which

suffocated 1,700 people and 3,500 livestock in nearby

villages.

Lake Nyos Demonstration

Sodium hydrogen carbonate is added to Nitric Acid in a large bottle. When they react together, carbon dioxide gas is produced.

Carbon dioxide is heavier than air and will stay in the bottle. Wait a few minutes until the reaction is complete. Pour the carbon dioxide into the container. The candle lowest down should go out first. This demonstrates that carbon dioxide is more dense than air.

Testing for Gases - Summary

Copy and complete the following sentences in your jotter.

The test for oxygen gas is that it ________________ a glowing splint.

The test for hydrogen is that it “_______” with a burning splint.

The test for carbon dioxide is that it turns limewater from

___________ to ____________.

Ring of Fire

Your teacher may let you try the ring of fire for Properties and Usesof Substances.

Pupils can be placed in a ring. Each pupil should be given a cardwhich has a question on the top and an answer on the bottom.The first pupil should read out their question and the pupil with thecorrect answer should shout it out and also read out their question. This continues until all the questions have been answered.

http://www.youtube.com/watch?v=0lhf9U5Wf3Q

Summary

Oxygen makes up 21% of the air. Nitrogen makes up 79% of the air. It can be used to

make fertilizers. Carbon dioxide can be used to make drinks fizzy.

Like all the noble gases, Argon is very unreactive.