Hydrochloric acid reacts with solid B - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2021 - Paper 1
Question 4
Hydrochloric acid reacts with solid B.
Solid B is an alkali.
A student carries out an experiment to see how the pH changes when different masses of solid B are adde... show full transcript
Worked Solution & Example Answer:Hydrochloric acid reacts with solid B - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2021 - Paper 1
Step 1
(i) Give a safety precaution that should be taken during the experiment.
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Answer
One important safety precaution is to wear safety goggles to protect the eyes from splashes of hydrochloric acid.
Step 2
(ii) Give an improvement to step 4 that would produce more accurate results.
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An improvement would be to use a precise balance to measure the exact mass of solid B added rather than using a spatula, which could lead to inconsistent amounts.
Step 3
(iii) What is the most likely change in pH during the experiment?
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The most likely change in pH during the experiment is from 1 to 7, as adding an alkali like solid B to hydrochloric acid will neutralize the acid, raising the pH.
Step 4
(iv) If some methyl orange indicator is added to the acid in step 2, the mixture changes colour during the experiment. State the colour change.
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colour at start in acid: red ____________ colour at end: yellow ____________
Step 5
(i) Give the name of the piece of apparatus labelled X.
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The piece of apparatus labelled X is a gas collection jar.
Step 6
(ii) The rod labelled Y in Figure 4 is made of graphite. What is the name of this piece of apparatus?
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The name of this piece of apparatus is an electrode.
Step 7
(iii) Give one reason why graphite is a suitable material to make Y.
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Graphite is a suitable material because it is a good conductor of electricity.
Step 8
(iv) Complete the balanced equation for the reaction that occurs.
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