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An impure hydrocarbon fuel is burned in the apparatus in Figure 5 - Edexcel - GCSE Chemistry Combined Science - Question 6 - 2020 - Paper 1
Question 6
An impure hydrocarbon fuel is burned in the apparatus in Figure 5. When the fuel is burned - the funnel becomes hot - a colourless liquid forms in tube A - the ind... show full transcript
Worked Solution & Example Answer:An impure hydrocarbon fuel is burned in the apparatus in Figure 5 - Edexcel - GCSE Chemistry Combined Science - Question 6 - 2020 - Paper 1
Step 1
The funnel becomes hot
Answer
When the impure hydrocarbon fuel is burned, it releases heat energy. This heat is transferred to the funnel, causing it to become hot. The combustion process generates thermal energy due to the exothermic reaction of burning fuel, leading to an increase in temperature of surrounding materials.
Step 2
A colourless liquid forms in tube A
Answer
As the hydrocarbon fuel burns, it produces water vapor and other products. When this vapor cools as it moves into tube A, it condenses into a liquid form, which is observed as a colourless liquid. This indicates the presence of water formed during combustion.
Step 3
The indicator in tube B changes colour to show an acidic gas
Answer
The combustion of hydrocarbons also produces carbon dioxide and possibly other acidic gases. When these gases enter tube B, they can react with the indicator solution, causing a color change. This color change illustrates that an acidic gas, likely carbon dioxide, is present, which can lower the pH of the solution.