Investigating Temperature Changes

This practical lesson covers:

  1. Temperature changes during neutralisation reactions, displacement reactions, combustion reactions and salts dissolving in water

Temperature changes during displacement reactions


Aim

To investigate the temperature change during a displacement reaction. 

Background information

Magnesium reacts with copper sulfate in a displacement reaction to produce magnesium sulfate and copper. This reaction releases energy, making it exothermic. In this practical, you will investigate the temperature change during this displacement reaction by measuring the initial temperature and the highest temperature reached. The difference in temperatures allows you to calculate the amount of energy released, demonstrating the exothermic nature of displacement reactions.

Equipment

  1. Thermometer
  2. Beaker
  3. polystyrene cup with lid
  4. cotton wool
  5. magnesium ribbon
  6. copper sulfate

Method 1 - temperature change during a displacement reaction

  1. Place the polystyrene cup in the beaker. 
  2. Surround the polystyrene cup with cotton wool. 
  3. Add 100 cm3 of copper sulfate to the cup. 
  4. Place thermometer in the cup and record the initial temperature. 
  5. Add magnesium ribbon to the cup and place the lid on. 
  6. Observe the temperature and record the highest temperature reached. 
  7. Calculate the amount of energy released.

What is the aim of investigating temperature changes during displacement reactions?

all of the above

to measure the initial temperature and the highest temperature reached during a displacement reaction

to demonstrate the exothermic nature of displacement reactions

to investigate the energy released during a displacement reaction

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What does an exothermic reaction do?

absorbs energy

both absorbs and releases energy

neither absorbs nor releases energy

releases energy

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What is the reaction between magnesium and copper sulfate called?

dissolving reaction

neutralisation reaction

combustion reaction

displacement reaction

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What happens during a combustion reaction?

a substance is dissolved in water

a substance is displaced

a substance is neutralised

a substance is burned in the presence of oxygen

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What is the formula used to calculate the amount of energy released from the combustion of ethanol?

q = c x ΔT

q = m x ΔT

q = m x c x ΔT

q = m x c

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