Chemistry 5070/42 — October/November 2013

Cambridge O-Level · Alternative to Practical · worked solutions for every part, with the mark scheme

questions

marks

minutes

Topics Experimental Contexts · Analysis, Conclusions and Evaluation · Observations and Measurements · Qualitative Analysis · Use of Techniques, Apparatus and Materials

Q18MExperimental ContextsObservations and MeasurementsAnalysis, Conclusions and EvaluationUse of Techniques, Apparatus and MaterialsFree sample

Approximately $4\text{ g}$ of sodium hydroxide is added to $100\text{ cm}^3$ of water. A thermometer is used to measure the temperature of the liquid both before and after the addition of sodium hydroxide.

The diagrams below show parts of the thermometer stem giving the two temperatures.

Fig. 1.1

(a)

Complete the table and calculate the change in temperature.

temperature $\text{T}_2$ after sodium hydroxide is added / $^\circ\text{C}$
temperature $\text{T}_1$ before sodium hydroxide is added / $^\circ\text{C}$
change in temperature / $^\circ\text{C}$

(b)

(i)

What type of process does this temperature change suggest has taken place?

______

(ii)

Complete the energy profile diagram for sodium hydroxide dissolving in water.
On your diagram label

the products,
the enthalpy change, $\Delta H$ .

Fig. 1.2

(c)

(i)

If aqueous litmus is added to aqueous sodium hydroxide, what colour is the resulting solution?

______

(ii)

How can the pH of aqueous sodium hydroxide be determined?

______

(iii)

Suggest a value for the pH of aqueous sodium hydroxide.

______

The rest of this paper

8 more questions

Q2Experimental Contexts · Analysis, Conclusions and Evaluation · Qualitative Analysis11M
Q3Experimental Contexts1M
Q4Use of Techniques, Apparatus and Materials1M
Q5Experimental Contexts1M
Q6Analysis, Conclusions and Evaluation1M
Q7Analysis, Conclusions and Evaluation · Experimental Contexts · Qualitative Analysis · Observations and Measurements15M
Q8Qualitative Analysis · Analysis, Conclusions and Evaluation8M
Q9Experimental Contexts · Analysis, Conclusions and Evaluation · Observations and Measurements14M

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