Core practical - Energy changes (AQA GCSE Chemistry): Flashcards
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Practise the cards
14 cards from this deck
Type of energy change in chemical reactions
Type of energy change in chemical reactions
Release or absorb energy
Effect when acids react with metals/carbonates/alkalis
Effect when acids react with metals/carbonates/alkalis
Temperature changes
Why use a polystyrene cup in this experiment
Why use a polystyrene cup in this experiment
Poor conductor of heat, keeps heat in
Why add excess zinc powder
Why add excess zinc powder
Ensures all acid reacts completely
What temperature is measured at the start
What temperature is measured at the start
Starting/initial temperature of acid
Temperature that shows energy released
Temperature that shows energy released
Maximum temperature
Why stir zinc vigorously
Why stir zinc vigorously
For complete reaction/mixing
Pattern: more acid present leads to...
Pattern: more acid present leads to...
Higher temperature rise
Type of reaction: zinc + hydrochloric acid
Type of reaction: zinc + hydrochloric acid
Exothermic reaction
What exothermic reactions do
What exothermic reactions do
Release heat energy, cause temperature to rise
Why keep total volume same (50 ) each time
Why keep total volume same (50 ) each time
Makes comparison fair
Effect of more concentrated acid
Effect of more concentrated acid
Bigger temperature rises
Essential safety equipment for this practical
Essential safety equipment for this practical
Eye protection
What polystyrene cup prevents
What polystyrene cup prevents
Heat loss to surroundings