10 exam-style questions on Chemistry · Industrial chemistry, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Ten Chemistry · Industrial chemistry questions with answers
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. In the manufacture of urea, ammonia and carbon dioxide first combine to form an intermediate, which then loses water to give urea. The intermediate is
A
ammonium carbonate, (NH4)2CO3
B
ammonium cyanate, NH4CNO
C
ammonium carbamate, NH2COONH4
D
ammonium hydrogencarbonate, NH4HCO3
Show answer
Answer: C. 2NH3 + CO2 → NH2COONH4, then NH2COONH4 → NH2CONH2 + H2O. Ammonium cyanate gives urea in Wöhler's laboratory synthesis, not in the industrial process.
2. The main purpose of cracking heavy petroleum fractions is to
A
separate crude oil by boiling point
B
convert straight chains into branched and aromatic ones
C
produce more petrol and alkenes from large molecules
D
remove sulphur compounds from the fuel
Show answer
Answer: C. Heavy fractions are in surplus while petrol and alkenes such as ethene and propene are in demand, so long chains are broken into shorter alkanes and alkenes. Turning straight chains into branched and aromatic hydrocarbons is reforming.
3. What mass of urea, CO(NH2)2, supplies 14 kg of nitrogen to a field? (H = 1, C = 12, N = 14, O = 16)
A
60 kg
B
15 kg
C
6.5 kg
D
30 kg
Show answer
Answer: D. M(urea) = 60, and every 60 kg of urea contains 2 × 14 = 28 kg of nitrogen. So 14 kg of nitrogen needs 60 × 14 ÷ 28 = 30 kg of urea. Counting only one nitrogen atom per molecule gives 60 kg.
4. Which product of cracking is the starting material for polyethene, ethanol and ethane-1,2-diol?
A
methane
B
propene
C
benzene
D
ethene
Show answer
Answer: D. Ethene polymerises to polyethene, adds steam to give ethanol, and is oxidised (through epoxyethane) and hydrated to ethane-1,2-diol. Propene is the monomer of polypropene.
5. Triple superphosphate is made by treating rock phosphate with
A
phosphoric acid, giving no calcium sulphate
B
sulphuric acid, giving calcium sulphate as well
C
nitric acid, giving calcium nitrate as well
D
ammonia, giving ammonium phosphate
Show answer
Answer: A. Ca3(PO4)2 + 4H3PO4 → 3Ca(H2PO4)2, so the whole product is the soluble phosphate and its P2O5 content is much higher. Sulphuric acid gives single superphosphate, which also contains calcium sulphate.
6. On the octane-number scale for petrol, the value 100 is assigned to
A
2,3,4-trimethylpentane
B
n-heptane
C
n-octane
D
2,2,4-trimethylpentane
Show answer
Answer: D. Iso-octane, 2,2,4-trimethylpentane, a branched alkane that burns smoothly, is given 100, and n-heptane, which knocks badly, is given 0. A petrol rated 90 knocks like a mixture of 90% iso-octane and 10% n-heptane.
7. Reforming raises the octane number of petrol by
A
turning branched chains into straight-chain alkanes
B
breaking large alkane molecules into much smaller ones
C
turning straight chains into branched and aromatic ones
D
adding hydrogen to alkenes to give alkanes
Show answer
Answer: C. Branched alkanes and aromatic hydrocarbons such as benzene and toluene burn more smoothly (with less knocking) than straight-chain alkanes. Breaking large molecules into smaller ones is cracking.
8. Urea is manufactured industrially from
A
ammonia and nitric acid
B
ammonia and carbon dioxide
C
ammonia and sulphuric acid
D
nitrogen and methane
Show answer
Answer: B. Ammonia (from the Haber process) and carbon dioxide combine under pressure to give urea. Ammonia with nitric acid gives ammonium nitrate, and with sulphuric acid it gives ammonium sulphate.
9. Crude petroleum is separated into fractions such as petrol, kerosene and diesel by
A
fractional crystallisation
B
catalytic cracking
C
steam distillation
D
fractional distillation
Show answer
Answer: D. The fractions differ in boiling range, so they condense at different heights in a fractionating column. Cracking changes the molecules themselves rather than separating them.
10. Rock phosphate is a poor fertiliser on its own. Treating it with sulphuric acid gives single superphosphate, whose useful water-soluble component is
A
Ca3(PO4)2
B
CaHPO4
C
Ca(H2PO4)2
D
CaSO4·2H2O
Show answer
Answer: C. Ca3(PO4)2 + 2H2SO4 → Ca(H2PO4)2 + 2CaSO4. Rock phosphate itself, Ca3(PO4)2, is insoluble, and the calcium sulphate supplies no phosphorus.
Chemistry · Industrial chemistry: questions students ask
How many Chemistry · Industrial chemistry MCQs are there?
10, each with the answer and a short explanation, across 1 topics: Industrial chemistry. Every chapter test draws ten of them, so you can take it many times.
Is the MDCAT Chemistry chapter 20 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
