Question 36
Endothermic or exothermic?
In this series of experiments, you will try some of the reactions and processes and decide if the reaction or process gives out energy to the surroundings or absorbs energy from the surroundings.
You will need: beakers or polystyrene cups or other insulated containers; stirring rod; thermometer (do not use the thermometer for stirring the solutions); chemicals as listed below; safety glasses.
Here are some reactions and processes you could try.
- Sodium hydroxide and dilute hydrochloric acid.
- Potassium chloride and water.
- Melting ice cubes.
- Copper sulfate solution and magnesium powder.
- Ammonium nitrate and water.
- Boiling water until steam comes off.
- Steam from a kettle directed at a cold surface.
- Dilute hydrochloric acid and magnesium ribbon.
- Sodium hydrogencarbonate and citric acid.
Method
Carry out some or all of the reactions or processes suggested. Make sure you do a risk assessment for each test that you do. You will need to adapt this method for processes that do not involve using two substances.
1. Construct a results table.
2. Place one of the solutions in the beaker or polystyrene cup.
3. Measure and record the temperature.
4. Add the other substance. Stir with the stirring rod.
5. Allow the substances to react, dissolve or change.
6. Measure and record the temperature.
7. Clean the thermometer and the stirring rod before using them for the next test.
8. For each test you did, say if it is endothermic or exothermic and if it is a reaction or process.
In this series of experiments, you will try some of the reactions and processes and decide if the reaction or process gives out energy to the surroundings or absorbs energy from the surroundings.
You will need: beakers or polystyrene cups or other insulated containers; stirring rod; thermometer (do not use the thermometer for stirring the solutions); chemicals as listed below; safety glasses.
Here are some reactions and processes you could try.
- Sodium hydroxide and dilute hydrochloric acid.
- Potassium chloride and water.
- Melting ice cubes.
- Copper sulfate solution and magnesium powder.
- Ammonium nitrate and water.
- Boiling water until steam comes off.
- Steam from a kettle directed at a cold surface.
- Dilute hydrochloric acid and magnesium ribbon.
- Sodium hydrogencarbonate and citric acid.
Method
Carry out some or all of the reactions or processes suggested. Make sure you do a risk assessment for each test that you do. You will need to adapt this method for processes that do not involve using two substances.
1. Construct a results table.
2. Place one of the solutions in the beaker or polystyrene cup.
3. Measure and record the temperature.
4. Add the other substance. Stir with the stirring rod.
5. Allow the substances to react, dissolve or change.
6. Measure and record the temperature.
7. Clean the thermometer and the stirring rod before using them for the next test.
8. For each test you did, say if it is endothermic or exothermic and if it is a reaction or process.
