3 Quantitative chemistry

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Question 3

A student investigated the change in mass when zinc carbonate was heated.

The word equation for the reaction is:

\text{zinc carbonate} \rightarrow \text{zinc oxide} + \text{carbon dioxide}

This is the method used:

Add $g3.75\text{ g}$ of zinc carbonate to an empty crucible with a lid.
Measure the mass of the crucible, lid, and contents.
Heat the crucible and contents strongly for 2 minutes.
Allow the crucible and contents to cool.
Measure the mass of the crucible, lid, and contents.
Repeat steps 3 to 5 until the mass of the crucible, lid, and contents does not change.

Table 1 shows the results.

Table 1

Total heating time in minutes	Mass of crucible, lid, and contents in grams
0	42.65
2	41.85
4	41.33
6	41.33

Questions:

Determine the mass of the empty crucible and lid.

[1]

Explain why the mass of the crucible, lid, and contents decreased.

[2]

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

[1]

When $g125.4\text{ g}$ of zinc carbonate is heated until the mass does not change, $kJ118\text{ kJ}$ of energy is taken in. The student heated $g3.75\text{ g}$ of zinc carbonate until the mass did not change. Calculate the energy taken in during this reaction. Give your answer to 3 significant figures.

[2]

What type of reaction, in terms of energy transfer, takes place when zinc carbonate is heated?

[1]

3 Quantitative chemistry

Question 3

A student investigated the change in mass when zinc carbonate was heated.

The word equation for the reaction is:

\text{zinc carbonate} \rightarrow \text{zinc oxide} + \text{carbon dioxide}

This is the method used:

Add $g3.75\text{ g}$ of zinc carbonate to an empty crucible with a lid.
Measure the mass of the crucible, lid, and contents.
Heat the crucible and contents strongly for 2 minutes.
Allow the crucible and contents to cool.
Measure the mass of the crucible, lid, and contents.
Repeat steps 3 to 5 until the mass of the crucible, lid, and contents does not change.

Table 1 shows the results.

Table 1

Total heating time in minutes	Mass of crucible, lid, and contents in grams
0	42.65
2	41.85
4	41.33
6	41.33

Questions:

Determine the mass of the empty crucible and lid.

[1]

Explain why the mass of the crucible, lid, and contents decreased.

[2]

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

[1]

[2]

What type of reaction, in terms of energy transfer, takes place when zinc carbonate is heated?

[1]

3 Quantitative chemistry

Question 3

Table 1

Markscheme

3 Quantitative chemistry

Question 3

Table 1

Markscheme

3 Quantitative chemistry

Question 3

Table 1

3 Quantitative chemistry Questions

3 Quantitative chemistry

Question 3

Table 1

3 Quantitative chemistry Questions