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3 Quantitative chemistry

3 Quantitative chemistry

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Question 70

A student investigated the change in mass when hydrated nickel sulfate was heated.

The word equation for the reaction is:

hydrated nickel sulfate⇌anhydrous nickel sulfate+water \text{hydrated nickel sulfate} \rightleftharpoons \text{anhydrous nickel sulfate} + \text{water} hydrated nickel sulfate⇌anhydrous nickel sulfate+water

This is the method used:

  1. Add 4.20 g4.20\text{ g}4.20 g of hydrated nickel sulfate to an empty crucible.
  2. Measure the mass of the crucible and contents.
  3. Heat the crucible and contents strongly for 1 minute.
  4. Allow the crucible and contents to cool.
  5. Measure the mass of the crucible and contents.
  6. Repeat steps 3 to 5 until the mass of the crucible and contents does not change.

The table below shows the results.

Total heating time in minutesMass of crucible and contents in grams
026.50
124.85
224.30
324.30
a.

Determine the mass of the empty crucible.

[2]
b.

Explain why the mass of the crucible and contents decreased.

[2]
c.

Suggest why the crucible and contents were heated until the mass did not change.

[1]
d.

When 200 g200\text{ g}200 g of hydrated nickel sulfate is heated until the mass does not change, 68.4 kJ68.4\text{ kJ}68.4 kJ of energy is taken in. The student heated 4.20 g4.20\text{ g}4.20 g of hydrated nickel sulfate until the mass did not change. Calculate the energy taken in during this reaction. Give your answer to 3 significant figures.

[3]
e.

What type of reaction takes place when hydrated nickel sulfate is heated?

[1]
Markscheme

3 Quantitative chemistry Questions

  1. GCSE
  2. /Chemistry
  3. /3 Quantitative chemistry

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