Practise Edexcel IGCSE Chemistry observations, measurements and variables by using colour, effervescence, gas collection and controlled variables.
A student uses this apparatus to investigate the rate of reaction between dilute sulfuric acid and an excess of small pieces of zinc.
This is the student's method.
Step 1 use of dilute sulfuric acid
Step 2 add approximately 5 g of small zinc pieces to the sulfuric acid
Step 3 quickly connect the gas syringe
Step 4 record the reading on the gas syringe every 30 seconds until the reaction stops
State how the student would know when the reaction stops.
A student investigates the effect of temperature on the rate of reaction between two solutions, A and B . When the reaction occurs, the mixture turns from colourless to blue.
This is the student's method.
- pour of solution A into a conical flask
- add solution B and measure the temperature of the mixture
- record the time taken for the mixture to turn blue
The student repeats this method at different temperatures.
Give two variables that the student needs to keep constant in this investigation.
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A student uses this apparatus to investigate the rate of reaction between marble chips and dilute hydrochloric acid.
This is the equation for the reaction.
The student repeats the experiment with hydrochloric acid at a higher temperature to investigate the effect on the rate of reaction.
Give two variables that should be controlled to make sure the results are valid.
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