Ammonium sulfate is a salt. It is used as a fertiliser. A student prepares some ammonium sulfate crystals by neutralisation. She uses dilute sulfuric acid and aqueous ammonia. The diagrams show some of the apparatus the student can use. (a) The student measures $25.0\text{ cm}^3$ of aqueous ammonia into a conical flask. Write the letter of the piece of apparatus she should use to measure the aqueous ammonia. Name this piece of apparatus. letter \_\_\_\_\_\_ name =…

Chemistry 5070/41 — May/June 2019

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

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

Q112MUse of Techniques, Apparatus and MaterialsQualitative AnalysisPlanning Experiments and InvestigationsExperimental ContextsObservations and MeasurementsFree sample

Ammonium sulfate is a salt. It is used as a fertiliser.

A student prepares some ammonium sulfate crystals by neutralisation.

She uses dilute sulfuric acid and aqueous ammonia.

The diagrams show some of the apparatus the student can use.

Fig. 1.1

(a)

The student measures $25.0\text{ cm}^3$ of aqueous ammonia into a conical flask.

Write the letter of the piece of apparatus she should use to measure the aqueous ammonia.

Name this piece of apparatus.

letter ______
name = ______

(b)

(i)

The student:

adds a few drops of methyl orange indicator to the aqueous ammonia in the conical flask
adds dilute sulfuric acid until the indicator changes colour
records the volume of dilute sulfuric acid added.

She uses the apparatus shown in the diagram to add the sulfuric acid.

Fig. 1.2

Name this piece of apparatus.

______

(ii)

What is the colour of methyl orange indicator:

in aqueous ammonia ______
in dilute sulfuric acid? ______

(c)

At the end-point the student records that $12.5\text{ cm}^3$ of $0.100\text{ mol / dm}^3$ sulfuric acid has neutralised $25.0\text{ cm}^3$ of $0.100\text{ mol / dm}^3$ ammonia.

Plan an experiment to prepare a pure sample of ammonium sulfate crystals.

You should use:

$0.100\text{ mol / dm}^3$ sulfuric acid
$0.100\text{ mol / dm}^3$ ammonia
the apparatus normally found in a chemistry laboratory.

(d)

Calcium hydroxide is used to neutralise soil acidity. It reacts with ammonium sulfate fertiliser in the soil.

The student investigates the reaction between these two compounds.

She uses the apparatus shown.

Fig. 1.3

(i)

What volume of gas is in the gas syringe?

______ $\text{cm}^3$

(ii)

After the gas has been collected, a piece of damp blue litmus paper and a piece of damp red litmus paper are put in the gas.

What happens to the colour of:

the damp blue litmus paper ______
the damp red litmus paper? ______

The rest of this paper

5 more questions

Q2Analysis, Conclusions and Evaluation · Experimental Contexts11M
Q3Analysis, Conclusions and Evaluation · Observations and Measurements · Experimental Contexts · Use of Techniques, Apparatus and Materials7M
Q4Experimental Contexts · Qualitative Analysis5M
Q5Experimental Contexts · Use of Techniques, Apparatus and Materials · Qualitative Analysis · Observations and Measurements · Analysis, Conclusions and Evaluation16M
Q6Analysis, Conclusions and Evaluation · Experimental Contexts9M

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