Starter quiz
- What is a sign that a chemical reaction is endothermic?
- The reaction mixture heats up.
- The reaction mixture cools down. ✓
- The reaction produces light.
- The reaction produces a sound.
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- Why is it important to only change one independent variable at a time in an experiment?
- To ensure that the experiment is more complex.
- To make sure the experiment is quickly completed.
- To identify which variable is responsible for the observed changes. ✓
- To use all the available materials.
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- What is the main reason for repeating an experiment several times?
- To use up all the materials.
- To ensure the results are reliable and not due to chance. ✓
- To see if the experiment gives different results each time.
- Because it is always required in scientific research.
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- In an experiment to determine how temperature affects the solubility of a salt in water, what is the dependent variable?
- The type of salt used.
- The amount of water used.
- The temperature of the water.
- The solubility of the salt. ✓
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- Hydrochloric acid and magnesium react to produce hydrogen gas. Identify the variable for an investigation to see how the mass of magnesium affects the volume of gas produced.
- independent variable⇔mass of magnesium used (g) ✓
- dependent variable⇔volume of gas produced (cm³) ✓
- control variable⇔volume of acid used (cm³) ✓
- A ______ variable is any variable that is kept constant throughout the experiment to ensure that the test results are due solely to the change in the independent variable.
- 'control' ✓
Exit quiz
- Which one of the following is a correct statement about combustion?
- The process of dissolving a substance in water.
- A chemical reaction in which a compound reacts with oxygen. ✓
- The process of a liquid turning into a gas.
- Whenever energy is released in a chemical reaction.
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- If the independent variable is the type of fuel, what would the dependent variable be in an experiment comparing energy transfer?
- The mass of the fuel.
- The volume of water being heated.
- The temperature increase of the water. ✓
- The time it takes to heat the water.
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- A ______ is a substance that releases its stored energy when it undergoes combustion. It's crucial for the process of energy transfer by heating.
- 'fuel' ✓
- Why is it important to use the same mass of fuel for each measurement when comparing the energy released by burning different fuels?
- To ensure the experiment takes the same amount of time for each fuel.
- To make sure the experiment is fair by only changing the type of fuel. ✓
- To prevent any accidents during the experiment.
- To use up all the fuel available.
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- Order the following steps to correctly set up an experiment comparing the energy transferred by different fuels, starting with recording the starting mass of each fuel.
- 1⇔Record the mass of each fuel (should be the same).
- 2⇔Record the starting temperature of the water.
- 3⇔Heat water in a boiling tube by burning the fuel.
- 4⇔Measure the temperature increase of the water.
- What role do control variables play in an experiment comparing the energy transferred by burning different fuels?
- They are the different types of fuels being tested.
- They are the outcomes measured in the experiment.
- They ensure the test remains fair by keeping certain conditions the same. ✓
- They are changed to observe different results.
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Worksheet
Presentation
Video
Lesson Details
Key learning points
- Burning a fuel transfers energy by heating its surroundings.
- Heating water in a boiling tube allows the amounts of energy transferred by different fuels to be compared.
- The mass of fuel used needs to be the same for each measurement.
- The temperature and volume of water being heated needs to be the same for each measurement.
Common misconception
Pupils get easily confused between variables and how to ensure a fair test.
Ensure that pupils understand the independent variable is the type of fuel, the dependent variable is the temperature increase and control variables are mass of fuel and volume of water.
Keywords
Combustion - In a combustion reaction, fuel is burned and reacts with oxygen to release energy.
Fair test - In a fair test, variables are controlled so that only one change affects the dependent variable.
Control variables - Control variables are all variables, other than the independent and dependent variables, that are kept constant/the same in an investigation.
Fuel - A fuel is a substance that releases its stored energy when it undergoes combustion.
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