Chemistry 5070/42 — October/November 2012

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 · Use of Techniques, Apparatus and Materials · Qualitative Analysis

Q16MObservations and MeasurementsQualitative AnalysisExperimental ContextsAnalysis, Conclusions and EvaluationFree sample

(a)

A student pours aqueous silver nitrate into a measuring cylinder.

Fig. 1.1

What is the volume of aqueous silver nitrate in the measuring cylinder?

______ $\text{cm}^3$

(b)

The student transfers the aqueous silver nitrate into a beaker containing excess aqueous potassium iodide. A precipitate of silver iodide is formed.

What colour is silver iodide?

______

(c)

The student separates the silver iodide precipitate from the solution.

Name the separation process.

______

(d)

The student dries and weighs the silver iodide.

mass of silver iodide = 4.70 g

Calculate the number of moles of silver iodide in this mass.
[ $A_r$ : Ag, 108; I, 127]

______ moles

(e)

The concentration of aqueous potassium iodide used is $1.00\text{ mol / dm}^3$ . It reacts with aqueous silver nitrate according to the following equation.

\text{AgNO}_3 + \text{KI} \rightarrow \text{AgI} + \text{KNO}_3

Using your answer from (d), deduce the number of moles of silver nitrate used in the reaction.

______ moles

(f)

Using your answers to (a) and (e) calculate the concentration of the aqueous silver nitrate.

______ $\text{mol / dm}^3$

The rest of this paper

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Q3Experimental Contexts · Use of Techniques, Apparatus and Materials · Observations and Measurements8M
Q4Experimental Contexts1M
Q5Analysis, Conclusions and Evaluation1M
Q6Experimental Contexts · Analysis, Conclusions and Evaluation1M
Q7Experimental Contexts · Analysis, Conclusions and Evaluation1M
Q8Observations and Measurements · Experimental Contexts · Use of Techniques, Apparatus and Materials · Analysis, Conclusions and Evaluation16M
Q9Experimental Contexts · Qualitative Analysis · Analysis, Conclusions and Evaluation · Observations and Measurements8M
Q10Observations and Measurements · Analysis, Conclusions and Evaluation · Experimental Contexts · Use of Techniques, Apparatus and Materials10M

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