Chemistry 5070/42 — May/June 2010

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

Q19MUse of Techniques, Apparatus and MaterialsQualitative AnalysisObservations and MeasurementsExperimental ContextsAnalysis, Conclusions and EvaluationFree sample

A student added $100\text{ cm}^3$ of $0.100\text{ mol/dm}^3$ hydrochloric acid (an excess) to a known mass of calcium carbonate contained in a conical flask. The reaction produced carbon dioxide according to the following equation.

$\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{H}_2\text{O} + \text{CO}_2$

The apparatus is shown below.

Fig. 1.1

(a)

Name the apparatus labelled A.

______

(b)

Give a test to confirm the presence of carbon dioxide.

test ______

observation ______

(c)

The diagram below shows apparatus A at the completion of the reaction.

Fig. 1.2

What volume of carbon dioxide was collected?

______ $\text{cm}^3$

(d)

Using your answer to (c), calculate the number of moles of carbon dioxide produced in the reaction.
[One mole of a gas occupies $24\,000\text{ cm}^3$ at room temperature and pressure.]

______ moles

(e)

(i)

Using the equation for the reaction and your answer to (d), suggest the number of moles of calcium carbonate that reacted with $0.100\text{ mol/dm}^3$ hydrochloric acid.

______ moles

(ii)

Calculate the relative formula mass of calcium carbonate, $\text{CaCO}_3$ .
[ $A_r$ : $\text{Ca}, 40$ ; $\text{C}, 12$ ; $\text{O}, 16$ ]

______

(iii)

Using your answers to (e)(i) and (ii), calculate the mass of calcium carbonate that reacted with $0.100\text{ mol/dm}^3$ hydrochloric acid.

______ $\text{g}$

(f)

The experiment was repeated using magnesium carbonate instead of calcium carbonate. The mass of magnesium carbonate used was identical to the mass of calcium carbonate in the previous experiment.
Calculate the volume of carbon dioxide collected.
[ $A_r$ : $\text{Mg}, 24$ ; $\text{C}, 12$ ; $\text{O}, 16$ ]

______ $\text{cm}^3$

The rest of this paper

9 more questions

Q2Experimental Contexts8M
Q3Experimental Contexts1M
Q4Experimental Contexts · Analysis, Conclusions and Evaluation1M
Q5Experimental Contexts1M
Q6Experimental Contexts · Analysis, Conclusions and Evaluation1M
Q7Experimental Contexts · Analysis, Conclusions and Evaluation1M
Q8Use of Techniques, Apparatus and Materials · Experimental Contexts · Observations and Measurements · Analysis, Conclusions and Evaluation12M
Q9Qualitative Analysis · Experimental Contexts13M
Q10Experimental Contexts · Observations and Measurements · Analysis, Conclusions and Evaluation13M

Loading the full paper…