FuelsIB MYP Sciences: Topic test

1. 1
   A fire safety instructor in Johannesburg shows staff what to do when cooking oil in a pan on an electric stove catches fire. She tells them to switch off the stove and then cover the pan with a fire blanket.

   (a)

   Which three things must be present together for a fire to burn?

   [1 mark]

   • AFuel, heat and oxygen
   • BFuel, water and nitrogen
   • COxygen, carbon dioxide and heat
   • DFuel, carbon dioxide and water

   (b)

   Which part of the fire triangle is removed first by switching off the electric stove?

   [1 mark]

   • AFuel
   • BOxygen
   • CHeat
   • DCarbon dioxide

   (c)

   Explain, using the fire triangle, why covering the pan with a fire blanket puts out the fire.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A camping supplier in Kuala Lumpur sells portable stoves that burn propane, C₃H₈, from small metal canisters. Propane is one of the gases obtained from crude oil.

   (a)

   Which statement about propane is correct?

   [1 mark]

   • AIt is a mixture of many different hydrocarbons
   • BIt is a hydrocarbon that contains only carbon and hydrogen atoms
   • CIt is a compound of carbon, hydrogen and oxygen
   • DIt is an element that burns to make only water

   (b)

   Ethane is another alkane and its molecules contain two carbon atoms. What is the formula of ethane?

   [1 mark]

   • ACH₄
   • BC₂H₄
   • CC₂H₈
   • DC₂H₆

   (c)

   Write a balanced symbol equation for the complete combustion of propane.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A shipping company in Busan runs its large container ships on fuel oil, a fraction of crude oil with very long hydrocarbon molecules, and its small harbour tugboats on diesel, a fraction with shorter molecules.

   (a)

   State three ways in which the properties of fuel oil differ from those of diesel.

   [3 marks]

   (b)

   Explain how fractional distillation separates crude oil into fractions such as fuel oil and diesel.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   In many homes in rural Kenya, families cook on open wood fires indoors. The smoke contains soot and carbon monoxide, which are made when wood burns in too little air. A charity proposes giving each household a stove with a chimney that burns bioethanol, a biofuel made from sugar-cane waste. A local school science club wants to investigate how air supply affects the soot made by a flame.

   (a)

   Plan an investigation to test a hypothesis about how the amount of air supplied to a Bunsen burner flame affects the amount of soot it produces. In your answer, state your hypothesis with a scientific reason, identify the variables, and describe a safe method.

   [6 marks]

   (b)

   Evaluate the charity's proposal to replace open wood fires with bioethanol stoves. Consider the social, economic and environmental impacts of the proposal, and reach a justified conclusion.

   [6 marks]

   Total for question 4: 12 marks

5. 5
   A coal-fired power station in Poland burns coal that contains a small amount of sulfur. Air, a mixture mainly of nitrogen and oxygen, is drawn into the furnace, which reaches a very high temperature.

   (a)

   Burning the sulfur in the coal makes a gas that causes acid rain. Which gas is it?

   [1 mark]

   • ACarbon monoxide
   • BCarbon dioxide
   • CNitrogen
   • DSulfur dioxide

   (b)

   At the very high temperature in the furnace, which pollutant forms from the nitrogen and oxygen in the air?

   [1 mark]

   • AMethane
   • BNitrogen oxides
   • CSoot
   • DHydrogen

   (c)

   Explain how burning this coal can lead to acid rain.

   [2 marks]

   Total for question 5: 4 marks

6. 6
   A dairy farm in Argentina keeps a large herd of cattle. The cattle and their manure release methane, and the farm's tractors burn diesel, which releases carbon dioxide. The farmer captures the methane from the manure and burns it to generate electricity for the farm.

   (a)

   Which pair of gases released on the farm are both greenhouse gases?

   [1 mark]

   • AOxygen and nitrogen
   • BNitrogen and hydrogen
   • CCarbon dioxide and methane
   • DHydrogen and oxygen

   (b)

   The farmer burns the methane completely. Which two products form?

   [1 mark]

   • ACarbon dioxide and water
   • BCarbon monoxide and water
   • CCarbon and hydrogen
   • DCarbon dioxide and hydrogen

   (c)

   Describe how greenhouse gases such as the carbon dioxide and methane from the farm cause the greenhouse effect to be enhanced.

   [2 marks]

   Total for question 6: 4 marks

7. 7
   A mechanic in Cairo warms up a petrol car in a closed garage. Petrol is a mixture of hydrocarbons. After twenty minutes he feels dizzy and has a headache, and the carbon monoxide alarm on the wall starts to sound.

   (a)

   Explain why carbon monoxide forms when petrol burns in the car engine.

   [3 marks]

   (b)

   Explain why carbon monoxide is dangerous, why an alarm is needed to detect it, and what the mechanic should do straight away.

   [4 marks]

   Total for question 7: 7 marks

8. 8
   A ferry operator in Hamburg is testing a ferry whose engine burns hydrogen instead of diesel. At present the hydrogen is made from natural gas, a process that releases carbon dioxide. Burning 1 kg of hydrogen releases about 120 MJ of energy, while burning 1 kg of diesel releases about 45 MJ.

   (a)

   Compare hydrogen and diesel as fuels for the ferry, using the data and your knowledge of combustion and pollutants.

   [6 marks]

   (b)

   Evaluate the operator's plan to replace its diesel ferries with hydrogen ferries. Consider the social, economic and environmental impacts, and reach a justified conclusion.

   [6 marks]

   Total for question 8: 12 marks

End of questions