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Chemical Reactions
Homework
Homework 1 – Chemical Reactions Are Everywhere!
You have discussed in class that chemical reactions are going on all around you. You
need to be very observant to watch out for the signs that a chemical reaction has
happened. After you have checked with your parents please try any TWO of the
following experiments at home. You must;
1. Describe the substances you used
2. Draw a labelled diagram of the equipment you used
3. Describe carefully what you observed
Experiment 1
Add a piece of clean egg shell to some vinegar in a small dish.
Experiment 2
Mix some milk and some vinegar together in a small dish.
Experiment 3
Put an old copper coin into a small amount of sauce (you could use tomato sauce, brown
sauce etc.) Leave it for 10 minutes then look carefully at the coin.
Homework 2 - Making New Substances
Question 1
Whenever a chemical reaction takes place a new substance must be formed (made). If
you watch a reaction carefully you can see signs that a new substance has been formed.
What are these signs that a new substance has been formed?
Question 2
Using the answer to question 1 to help you, decide if the following examples are
chemical reactions and EXPLAIN your answer:
a. When an egg is fried, the runny transparent white becomes a white solid.
b. When a piece of wood is burned it produces smoke and grey ash.
c. When boiled potatoes are mashed they form a smooth white paste.
d. When a kettle is boiled it produces steam which condenses on the cold windows.
Question 3
Read this passage then answer the question below:
It was Daniel’s birthday and his mum decided to bake a cake for him. She had to drive
her car to the shops to get the ingredients. On the way there she stopped to get
petrol. When she got back she put the gas oven on, to bake the cake. The cake was a
lovely golden colour when it came out of the oven and smelt wonderful. She made some
icing by mixing water and icing sugar together and made herself a cup of tea whilst the
icing went hard. Finally she added some birthday candles. After the birthday tea,
Daniel’s mum lit the candles. There were a lot of candles and she was worried that they
would melt all over the cake but Daniel blew them out first time. The cake was a great
success, it was all eaten up in no time. Daniel’s stomach was so full he could hardly move.
A lot of chemical reactions are going on in this passage. Can you find as many as
possible and make a list.
Homework 4 -
Elements and Compounds
Question1
Use your jotter and Periodic Table to find:
a. An element named after an American state.
b. A metal with a name that reminds you of a red precious stone.
c. A non-metal used in the swimming pool to kill germs.
d. The chemical symbol for sodium.
e. The symbol for a metal that is a liquid at room temperature.
f. A metal named after the woman who discovered Radium (use the internet to help
you!!)
g. A gas used to fill party balloons.
Question 2
Copy and Complete the following table using your rules on naming compounds to help you.
NAME OF COMPOUND
ELEMENTS PRESENT
SODIUM FLUORIDE
COPPER AND OXYGEN
LITHIUM SULPHIDE
COBALT AND CHLORINE
LEAD NITRATE
MAGNESIUM, SULPHUR AND OXYGEN
Homework 3 – Effervescence
A lot of chemical reactions produce gases. It is very important to be able to identify
these gases.
Question 1
Copy and Complete this paragraph:
When marble chips are added to acid the gas ________ ___________ is produced.
This gas can be identified by bubbling it through _______________. If the liquid
turns cloudy then_______ ________ has been produced.
Question 2
Name the gas which burns with a squeaky pop.
Question 3
Explain using a diagram how you would test a gas to see if it was oxygen.
Question 4
Read the information in the passage below and draw a bar graph to show this
information. Remember to label your axes and give it a title.
The newly discovered planet Alfred has a poisonous atmosphere containing 30%
chlorine, 20% carbon dioxide, 15% krypton , 30% oxygen. The rest is a mixture
of the other noble gases.
Homework 5 – Speeding Up Chemical Reactions
Sometimes it is very important to be able to speed up a chemical reaction. It can also
be important to slow them down.
Question 1
There are a lot of chemical reactions that can cause raw meat to become rotten. How
could you slow down the reactions which spoil food?
Question 2
Put these chemical reactions in order according to their speed, slowest first:
a. Hair growing
b. Cake baking
c. Match burning
d. Egg frying
Question 3
Joanne is trying to speed up the reaction of acid with marble chips. She tries a
number of changes to see which is the fastest. Look at her notes below and decide
which experiment will have the slowest reaction and which will have the fastest
reaction:
Experiment
1
2
3
4
Temperature of
acid (°C)
40
40
20
20
Particle size of
marble
Powder
Powder
Chunks
Chunks
Concentration of
acid (M)
1.0
2.0
1.0
2.0
Question 4
What everyday reaction would you like to be able to speed up and why?