A Student Pours Ammonium Nitrate

Sample exam questions -

Understanding how to approach exam questions helps to boost examination operation. Question types volition include multiple selection, structured, mathematical and applied questions. Arrangements for examination/non-examination assessments for students taking qualifications during the pandemic may be subject to change. Please bank check with your teacher.

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Six-mark questions

Six-marker questions are extended open response questions. These crave longer answers than the structured questions. It is wise to plan your answer rather than rushing straight into it, otherwise you may stray away from the key points.

To gain full marks, you demand to:

support explanations using scientific cognition and understanding
utilize appropriate scientific words and terms
write clearly and link ideas in a logical mode
maintain a sustained line of reasoning, rather than getting lost or bogged down

Six-marker questions ofttimes use these command words:

depict - yous need to requite an account but no reason
explicate - you must requite reasons or explanations
devise - yous must plan or invent a procedure using your scientific cognition and agreement
evaluate - y'all must review information, including identifying strengths and weaknesses, and make a supported conclusion

Half dozen-mark questions may be synoptic questions. These questions bring together ideas from two or more topics. For example, a question about fertilisers could include ideas virtually covalent substances, acids and alkalis, chemical calculations, and effects on the environment.

The answers shown here give marking points as bullet points. You do not usually demand to include all of them to gain six marks, merely you practise demand to write in full sentences, linking them logically and clearly.

Sample question 1 - Foundation

Question

Ammonium nitrate is a salt used as a fertiliser.

A student is told to apply four stages to prepare pure, dry crystals of ammonium nitrate:

have 25.0 cm ³ of ammonia solution
find the volume of nitric acid that is needed to neutralise the ammonia solution
utilise this event to fix an ammonium nitrate solution
ready pure, dry crystals of ammonium nitrate from this solution

Some of the post-obit appliance may be used in the experiment.

Four pieces of apparatus for an experiment, with the universal indicator labelled.

Describe how the student should carry out this experiment.

[6 marks]

Edexcel question courtesy of Pearson Education Ltd.

Your answer should include the post-obit:

Stage 1:

identifies pipette
pipette/measuring cylinder to measure out the ammonia solution (25 cm ³ )
into a suitable container, eg conical flask

Stage 2:

add few drops of indicator/suitable named indicator
put flask on a white tile
identifies burette
fill burette with nitric acid solution
clamp burette/burette holder/stand
read level of burette
add acid from the burette
swirl flask (gently)
add drib-wise near cease-point
until indicator just changes colour/correct colour modify for called indicator
read level on burette
repeat experiment until concordant results

Stage 3:

mix the aforementioned volumes of nitric acid and ammonia solution (determined from the titration experiment)
but leaving out the indicator

Stage four:

pour into an evaporating dish
estrus the solution/leave to evaporate to dryness, until pure table salt crystals formed
to indicate of crystallisation/concentrate solution
leave to absurd
filter off crystals
wash with water
leave to dry

Sample question 2 - Higher

Question

Ammonium sulfate is a salt used as a fertiliser. It can be prepared in the laboratory, and in fertiliser factories.

Compare and contrast these two means to prepare ammonium sulfate.

[6 marks]

This question has been written by a Bitesize consultant as a proposition to the type of question that may appear in an exam paper.

Your answer should include the following:

Similarities:

both employ ammonia/ammonia solution
both use sulfuric acid
both produce ammonium sulfate

Differences:

Feature	Laboratory grooming	Factory preparation
Calibration	Small	Large
Number of stages	Small number	Several/more
Starting materials	Ammonia solution and sulfuric acid	Raw materials for making ammonia solution and sulfuric acid/named raw textile, eg air, water, natural gas, sulfur
Blazon of process	Batch	Continuous

Sample question iii - College

Question

The reaction betwixt nitrogen and hydrogen is exothermic.

N ₂ (g) + 3H ₂ (grand) ⇌ 2NH ₃ (g)

Ane factory uses this prepare of conditions:

If nitrogen and hydrogen were reacted at 150 atm pressure and 300°C, without a catalyst, some ammonia would be formed.

Some other factory uses this set of conditions:

In the Haber process a pressure of 150 atm and a temperature of 450°C are used, in the presence of an iron catalyst.

Explain why the conditions used in the second factory volition generate more than profit using ideas nearly yield and rate.

[6 marks]

Edexcel question courtesy of Pearson Education Ltd.

Your answer should include the following:

higher temperature reaches equilibrium faster because molecules move faster
therefore there are more frequent collisions considering molecules have more energy
therefore more than collisions take required energy but yield will exist lower
this is considering higher temperature favours endothermic reaction and and then equilibrium shifts to left-mitt side
which is because of decomposition of ammonia/ammonia reforms elements
catalyst causes reaction to reach equilibrium faster/catalyse
this increases rates (of both forward and back reactions)
this lowers the activation free energy (of both forward and back reactions) only does not affect yield
equilibrium position not affected

Sample question 4 - Higher

Question

Pure metal can be converted into alloys.

In many cases alloys are more useful than pure metals, for example they are stronger. Gold alloys, stainless steel and magnalium are examples of useful alloys.

Depict how alloying improves the usefulness of metals and how force is increased, using ideas about the structure of the alloy.

You lot may use diagrams to help your answer.

[6 marks]

Edexcel question courtesy of Pearson Education Ltd.

Your answer should include the following:

Property alter (other than increased strength) or use of blend:

increased hardness
decreased malleability
increased corrosion resistance
gilded blend for jewellery
stainless steel used for cutlery
steel used for construction
magnalium used for aircraft
idea of whatever utilise of metal later alloying

Iron:

iron is a more than reactive metal than gilded and less reactive than aluminium/heart of reactivity series
found combined with other elements
information technology is extracted by heating with carbon
carbon is more reactive than iron
electrolysis can be used
simply electrolysis is more expensive (than heating with carbon)

Structural change:

pure metal - atoms are all the same size/suitable diagram of pure metallic structure
atoms arranged in a regular mode/lattice
alloy - atoms are of different sizes/suitable diagram of alloy construction
disrupts organization of atoms
atoms in pure metal structure tin can slide over each (when bent)
alloy - sliding prevented past different sized atoms

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