The reactivity of copper, magnesium and zinc was investigated - Edexcel - GCSE Chemistry - Question 5 - 2019 - Paper 1
Question 5
The reactivity of copper, magnesium and zinc was investigated.
Each metal was placed separately in dilute hydrochloric acid.
The amount of effervescence was observed... show full transcript
Worked Solution & Example Answer:The reactivity of copper, magnesium and zinc was investigated - Edexcel - GCSE Chemistry - Question 5 - 2019 - Paper 1
Step 1
(i) The same mass of metal was used in each experiment. Which piece of apparatus should be used to find the mass of metal used?
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Answer
The correct piece of apparatus to find the mass of metal used is A a balance. A balance is necessary for accurate measurement of the mass.
Step 2
(ii) State two variables, apart from the mass of the metals, that should be controlled in this investigation.
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Answer
Two variables that should be controlled are:
The concentration of the hydrochloric acid used in each experiment.
The temperature of the reaction environment.
Step 3
(iii) Magnesium produces the most vigorous effervescence. Copper does not produce any effervescence. Give the reason why copper does not produce any effervescence.
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Answer
Copper does not produce any effervescence because it is less reactive than hydrogen, meaning it does not displace hydrogen ions from the acid.
Step 4
(iv) The magnesium reacts with dilute hydrochloric acid to form magnesium chloride solution and hydrogen gas. Fill in the missing state symbols in the spaces provided.
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Answer
The completed equation is:
Mg(s)+2HCl(aq)→MgCl2(aq)+H2(g)
Therefore, the missing state symbols are (aq) for magnesium chloride and (g) for hydrogen.
Step 5
(i) Write the formula of potassium sulfate.
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The formula of potassium sulfate is K₂SO₄.
Step 6
(ii) Calculate the mean mass of potassium sulfate obtained, giving your answer to two decimal places.
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Answer
To calculate the mean mass of potassium sulfate, sum the masses obtained and divide by the number of experiments:
Mean=35.22+5.24+5.21=315.67=5.22extg
Thus, the mean mass of potassium sulfate is 5.22 g.
