Physical and Chemical Changes
You are going to carry out 4 experiments. Each experiment will be an example of a physical or a chemical change. You need to follow the instructions carefully for each experiment. You should also write down all observations you see during the
experiment.
Safety:
1. Wear goggles throughout the experiments.
2. If you get acid on your hand wash it off immediately.
3. If you get acid in your eye wash rinse it thoroughly.
4. Report any accidents to the teacher.
1. Cleaning Muddy Water
Aim: to clean the muddy water
Method: place a filter paper inside a funnel. Place the funnel over a conical flask.
Carefully pour a little of the muddy water into the funnel. Make sure the water does not go over the top of the paper or around the side of the paper. Let the water naturally soak through the paper do not try to force it through.
Draw your apparatus.
Results: Describe the water collected in the conical flask.
Is the water pure water? How could you check this?
Is the cleaning of muddy water a physical or chemical change? Explain your answer in detail.
2. Colours in Sweets
Aim: To separate the colours in sweets
Method: Cut a filter paper into a rectangle shape (3cm x 8cm). Draw a faint line in pencil about 1cm from the bottom of the rectangle.
Place a sweet into an evaporating dish. Drop a few drops of water over the top of the sweet until the outer layer of the sweet dissolves into the water. Place a drop of the coloured liquid onto the middle of the pencil line on the filter paper.
Place a small amount of water into the bottom of a beaker. The water level should be under the pencil line when the filter paper is placed into the water. Carefully place the filter paper into the water and secure it with a small piece of selotape to the top of the beaker so that it does not fall in.
Draw a diagram of your apparatus:
Results: describe what you observe as the water rises up through the filter paper?
Is the separation of colour in the sweet a physical or chemical change? Explain….
3. Mixing Substances
Aim: to react an acid with a sodium bicarbonate
Method: using a spatula measure about 1cm³ of sodium bicarbonate into a test tube.
Make sure the test tube is standing safely in a test tube rack. Into another test tube carefully pour about 3cm³ of ethanoic acid.
Draw a diagram of your apparatus:
Carefully pour the acid into the sodium bicoarbonate.
Results: Record all observations. What do you see, feel and smell….
Is the reaction between ethanoic acid and sodium bicarbonate a chemical or a physical change? Explain
Try to write a chemical equation for the reaction.
4. Cola and Mento
Aim: To react Cola with Mento
Method: carefully pour 50ml of cola into a large beaker. Carefully drop 1 mento into the beaker.
Draw your apparatus:
Results: record all your observations. What did you see, feel and smell….
Is the reaction between cola and a mento a chemical or a physical reaction? Explain your answer?
