Grade 12 Physical Sciences · Chemical Systems · Paper 2 (Chemistry)

Chemical Industry Grade 12

Chemical Industry practice questions and answers, with each memo split into ticks. Try one, mark yourself, and see exactly which skill cost you marks.

practice questions: 26 practice questions
skill: 1 skill
videos: 1 videos

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Practice · NavyBlue · 3 marks

The flow diagram shows how some fertilisers are made in industry. Nitrogen and hydrogen react in process A to form ammonia. Diagram for this question

Write a balanced equation for process A.(3)

Work it out on paper first. Then mark yourself with the memo, one tick at a time.

Chemical Industry skills

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Describe fertiliser productionDescribe how fertilisers are made, such as ammonia by the Haber process, read N:P:K ratios, and explain eutrophication.26 practice questions · 4 videos

More Chemical Industry Grade 12 questions and answers

Try each one on paper before you open the memo.

4. Practice · NavyBlue · 2 marks
In the Haber process: $N_{2} (g) + 3 H_{2} (g) ⇌ 2 NH_{3} (g)$ , $Δ H < 0$
Write down the approximate temperature and pressure used in industry.(2)
Show the memo (2 ticks)Memo
1. ✓
  TemperatureAbout $450^{\circ} C$ (accept $400$ to $500^{\circ} C$ )
  1 mark · Describe fertiliser production
2. ✓
  PressureAbout $200 atm$ ( $20 MPa$ ; accept $150$ to $300 atm$ )
  1 mark · Describe fertiliser production
5. Practice · NavyBlue · 3 marks
In the first step of the Ostwald process, ammonia reacts with oxygen to form nitrogen monoxide and water.
Write a balanced equation for this step.(3)
Show the memo (3 ticks)Memo
1. ✓
  Reactants $NH_{3} + O_{2}$
  1 mark · Describe fertiliser production
2. ✓
  Products $\to NO + H_{2} O$
  1 mark · Describe fertiliser production
3. ✓
  Balancing $4 NH_{3} + 5 O_{2} \to 4 NO + 6 H_{2} O$
  1 mark · Balance a chemical equation
6. Practice · NavyBlue · 2 marks
Sulfuric acid is made by the Contact process. In the key step, sulfur dioxide is converted into sulfur trioxide:
$2 SO_{2} (g) + O_{2} (g) ⇌ 2 SO_{3} (g)$
Sulfuric acid reacts with ammonia to make a fertiliser. Write a balanced equation for this reaction.(2)
Show the memo (2 ticks)Memo
1. ✓
  Reactants and product $NH_{3} + H_{2} SO_{4} \to (NH_{4})_{2} SO_{4}$
  1 mark · Describe fertiliser production
2. ✓
  Balancing $2 NH_{3} + H_{2} SO_{4} \to (NH_{4})_{2} SO_{4}$
  1 mark · Balance a chemical equation
7. Practice · NavyBlue · 2 marks
A farmer wants a fertiliser that mainly helps the roots of young plants to grow strongly. Which nutrient should be present in the HIGHEST proportion?(2)
1. A Nitrogen
2. B Phosphorus
3. C Potassium
4. D Carbon
Show the memo (2 ticks)Memo
1. ✓
  NutrientPhosphorus promotes root growth (and flowering). Nitrogen mainly promotes leaf growth; potassium helps fruit and disease resistance. Plants get carbon from the air.
  
  Answer: B
  2 marks · Describe fertiliser production
8. Practice · NavyBlue · 2 marks
A gardener needs $0, 6 kg$ of nitrogen for a vegetable patch. The fertiliser available is labelled $5 : 1 : 4 (30)$ . Calculate the mass of fertiliser the gardener needs.(2)
Show the memo (2 ticks)Memo
1. ✓
  Mass of nutrientsN is $\frac{5}{10}$ of the nutrients: nutrients $= 0, 6 \times \frac{10}{5} = 1, 2 kg$
  1 mark · Describe fertiliser production
2. ✓
  Mass of fertiliserNutrients are $30%$ of the fertiliser: $m = \frac{1 , 2}{0 , 30} = 4 kg$
  1 mark · Describe fertiliser production
9. Practice · NavyBlue · 2 marks
The air is about $78%$ nitrogen, yet plants can still lack nitrogen. Explain why plants cannot use nitrogen gas directly, and name the industrial process that converts it into a form used to make fertilisers.(2)
Show the memo (2 ticks)Memo
1. ✓
  Reason $N_{2}$ is very unreactive because of its strong triple bond, so plants cannot absorb or use it; they need nitrogen as dissolved ions ( $NO_{3}^{-}$ or $NH_{4}^{+}$ ).
  1 mark · Describe fertiliser production
2. ✓
  ProcessThe Haber process (nitrogen to ammonia).
  1 mark · Describe fertiliser production
10. Practice · Siyavula Grade 12 Physical Sciences · Ex 14.2 · 1 mark
Ammonia and nitric acid react to form compound A. Compound A is soluble in water and can be used as a fertiliser.
(1) Write down the name and formula of compound A.(1)
Show the memo (1 tick)Memo
1. ✓
  Name and formulaAmmonium nitrate, $NH_{4} NO_{3}$
  1 mark · Describe fertiliser production
Question adapted from Siyavula Education (CC BY 3.0) · Solution by NavyBlue

Chemical Industry Grade 12 videos

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02 Processes in the Fertiliser IndustryMindset

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