Materials and Energy

Chemistry, HSSC-Punjab Second Year. This chapter is split into 27 topics and has 605 practice questions. The topics covered are listed below, followed by 10 free sample questions from the chapter.

Topics in this chapter

1. Toxicity of materials and types of hazard 20 questions
2. Polymers and composite materials 20 questions
3. Occurrence of metals: free state, ores and gangue 20 questions
4. Energy calculations using energy density and specific energy 22 questions
5. Catalytic reforming of hydrocarbons 26 questions
6. Environmental impact of energy use and sustainable energy sources 22 questions
7. Alloys: composition, properties and uses 22 questions
8. Heavy metals, plastics and microplastics 20 questions
9. X-ray crystallography and structure analysis 27 questions
10. Materials and their properties 20 questions
11. Recycling: benefits and energy saving 22 questions
12. Alloy composition calculations 26 questions
13. Energy density and specific energy 20 questions
14. Properties and uses of metals 20 questions
15. Roasting and calcination: equations and calculations 29 questions
16. Fossil fuels: sources, uses and effects 20 questions
17. Semiconductors 20 questions
18. Ceramics: composition, properties and applications 20 questions
19. Cracking of hydrocarbons 28 questions
20. Fractional distillation and refining of petroleum 21 questions
21. Nuclear fission and fusion 26 questions
22. Challenges in recycling and recycling methods 23 questions
23. Steps of metallurgy 21 questions
24. Solar energy and photovoltaic cells 20 questions
25. Electrolytic extraction and refining of metals 20 questions
26. Petrochemicals and their derivatives 20 questions
27. Reduction of metal oxides with carbon monoxide 30 questions

Sample questions: Materials and Energy

10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.

Q1. How does the book define a material?

• A. any pure element that is found only as free atoms in the earth's crust and is used for making all kinds of tools
• B. any metal or alloy that conducts electricity and heat well and can be drawn into wires
• C. any liquid or solid that can be used as a solvent or a cleaning agent in industry
• D. any substance or mixture of substances that makes up a physical object of daily or industrial use(correct answer)

Answer: D.The book defines a material as any substance or mixture of substances that makes up a physical object of daily-life or industrial importance.

Q2. Which statement about this chapter's scope is correct?

• A. it covers only the metallurgy of iron and steel and their uses in building
• B. it covers materials, X-ray crystallography, petrochemicals and energy sources(correct answer)
• C. it covers only the synthesis of organic compounds and their reactions in the laboratory
• D. it covers only nuclear energy, its safety and its waste

Answer: B.The introduction lists materials, analytical techniques such as X-ray crystallography, petrochemicals and fossil, nuclear and solar energy.

Q3. Why is the extraction of sodium more energy-intensive than the extraction of gold?

• A. gold is more reactive than sodium and so is much harder to extract
• B. sodium occurs free in nature, so it needs no extraction
• C. gold needs a large electric current to be extracted from its ore in a cell
• D. sodium is very reactive and needs electrolysis, while gold occurs in the free state(correct answer)

Answer: D.Sodium sits high in the reactivity series, exists in compounds and needs energy-intensive electrolysis; gold is found in the free state.

Q4. Why is the sensitivity of semiconductors to light, heat and voltage useful in electronics?

• A. it makes the material unsuitable for use in electronic devices
• B. it lets the current be controlled by these conditions(correct answer)
• C. it makes every semiconductor conduct like a metal at all times and temperatures
• D. it makes semiconductors perfect insulators under all conditions of use

Answer: B.The book says semiconductors are light, heat and voltage sensitive and that the current through them can be controlled in an application.

Q5. Which statement correctly describes the position of semiconductors between conductors and insulators?

• A. they conduct better than metals under all conditions of use and temperature
• B. they conduct only when they are heated until they are molten
• C. they never conduct under any condition, as ceramics do not
• D. they conduct in special conditions; metals always do and ceramics mostly do not(correct answer)

Answer: D.The chapter describes metals as good conductors, most ceramics as non-conductors and semiconductors as conducting only in special conditions.

Q6. Why is cracking necessary?

• A. cracking only removes the sulphur and water from crude oil
• B. crude oil contains no hydrocarbons at all but only water
• C. petrol cannot be burned in engines without first being cracked
• D. ethene and propene, the raw materials for plastics and rubber, are small molecules(correct answer)

Answer: D.The book says cracking is necessary since ethene and propene, smaller in weight, are the major raw materials for plastics and artificial rubber.

Q7. What is nuclear energy?

• A. the energy released by nuclei, when heavy nuclei split or light nuclei combine(correct answer)
• B. the energy released when atoms join to form molecules
• C. the energy of falling water in dams
• D. the energy stored in chemical bonds only, as in fuels

Answer: A.The book defines nuclear energy as energy released by nuclei, either when heavy nuclei are split (fission) or when light nuclei are combined (fusion).

Q8. Why do nuclear reactions release much more energy than chemical reactions (Quick Check 31.5d)?

From your book: Quick Check 31.5 (page 230) Full page Open book

• A. they involve only the movement of molecules in a gas
• B. they involve only electrons moving between orbitals of the atom
• C. they involve only the evaporation of water into steam
• D. they involve changes in the nucleus, where binding energies are far larger than bond energies(correct answer)

Answer: D.The book says nuclear reactions liberate extremely high quantities of energy compared with chemical reactions (standard explanation: nuclear binding energies are much larger).

Q9. Which energy sources does the book say we need to switch to because of shortages, high fuel prices and climate problems?

• A. diesel and petrol for vehicles
• B. solar, hydro and wind energy(correct answer)
• C. uranium and plutonium only
• D. coal, oil and natural gas

Answer: B.The book says energy shortages, high prices and climate problems show we need to switch to renewable sources like solar, hydro and wind.

Q10. Which statement about comparing fossil fuels, nuclear power and solar power is consistent with the chapter?

• A. all three produce exactly the same kind of waste
• B. none of the three has any drawback of any kind
• C. solar is the least clean and nuclear power the most renewable
• D. fossil fuels: efficient but polluting; nuclear: large energy with waste; solar: clean and renewable(correct answer)

Answer: D.The chapter highlights efficiency and pollution of fossil fuels, the waste and accident risk of fission, and the renewability of solar.