Fuels Flashcards
(1) Which row of the table describes propene?
hydrocarbon, unsaturated
(2) Propene can form the polymer poly(propene).
Draw a diagram to show the part of a poly(propene) molecule formed from two
propene molecules.
correct repeating unit(1)
• two correct units shown with
continuation bonds (1)
(2) ) Describe a test that shows that molecules of propene contain carbon to carbon double
bonds.
bromine (water) (1)
• (bromine water) turns (from
orange) to colourless/or is
decolourised (1)
(1) C10H22 → 2C3H6 + C4H10
decane propene butane
Give the total mass of products formed if 17 g of decane is cracked in this way
17 (g)
(2) Explain what is meant by cracking.
break down of hydrocarbons /
large molecules / alkanes (1)
• into small(er) molecules (1)
(2) Explain why it is necessary to crack crude oil fractions that contain large
molecules.
less demand for (fractions containing) large molecules ORA (1) • large molecules are less useful ORA (1)
(2) Suggest two reasons why it is usually difficult to burn different hydrocarbon fuels
efficiently in the same appliance.
• fuels can be in different states / specific example • different sized molecules(1) • different viscosities (1) • different boiling point / vaporisation temperatures (1) • different ease of ignition /some fuels more flammable (1) • different amounts of air / oxygen needed (1)
(1) The fuels that can be used in the stove are obtained by the fractional distillation of
crude oil.
Which of these statements about the fractions obtained by the fractional distillation
of crude oil is correct?
diesel oil is used as a fuel for some trains
(3) Ethane, C2H6, is present in crude oil.
Write the balanced equation for the complete combustion of ethane.
2C2H6 + 7O2 → 4CO2 + 6H2O • reactant formulae (1) • product formulae (1) • balancing correct formulae (1)
(6) ) Petrol is the fuel used in many car engines.
Research is being carried out into the use of hydrogen instead of petrol.
Evaluate the advantages and disadvantages of using hydrogen rather than petrol as a
fuel for cars.
Advantages
• plenty of water / raw material
• limited supplies of crude oil
• hydrogen produces only water as waste
• petrol produces carbon dioxide
• carbon dioxide (emissions) may cause global warming
Disadvantages
• hydrogen has to be produced
• requires energy / electricity to produce it
• producing electricity from non-renewable sources produces
carbon dioxide
• expensive to produce
• problems of storage of large volumes of flammable gas
• stronger / heavier / bigger tanks needed
• hydrogen a gas, petrol a liquid, hydrogen leaks more likely
• limited outlets / conversion costs
• shorter distance between refuelling
(1) Which of the following statements is true
molecules in diesel are larger than molecules in petro
(2) Explain what is meant by cracking.
• break down of (hydrocarbons/molecules / alkanes) (1) • into smaller (hydrocarbons/molecules / alkanes) (1)
(3) Explain why ethene is described as an unsaturated hydrocarbon
(molecule) containing (carbon-carbon) double / multiple bond (1) • contains (atoms of) carbon and hydrogen (1) • only (1)
(2) Describe what you would see when a sample of ethene is shaken with
bromine water
from
orange/brown/yellow (1)
• to colourless (1)
(6) Explain how the presence of sulfur in fossil fuels can lead to damage to the
environment and how the amount of damage can be reduced.
cause of acid rain • burning sulfur • produces sulfur dioxide • escapes into atmosphere • dissolves in rain water • forming acidic solution / sulfurous / sulfuric acid • falls to the ground as acid rain effect of acid rain • acidification of lakes • kills fish • kills trees / forests • damage / erosion of stonework reduction of damage • calcium carbonate • from limestone • may be converted into calcium hydroxide • waste gases from power stations • passed through carbonate or hydroxide • removing sulfur dioxide
(1) Natural gas is a good fuel because
it produces no solid waste on complete combustion
(2) The complete combustion of fossil fuels releases gases into the atmosphere.
Explain how these gases could cause an increase in the temperature of the Earth
carbon dioxide / water vapour (released into the atmosphere) (1) • absorbs OWTTE heat (radiated from Earth)(1)
(1) State an advantage of replacing fossil fuels with biofuels made from plants
(biofuels) renewable / plants
remove carbon dioxide from
atmosphere / conserves fossil
fuels
(2) Explain a disadvantage of replacing fossil fuels with biofuels made from plants.
(growing crops for biofuels) requires land (1) • less land for food production / less food / deforestation / destroys habitat / food prices increase (1)
(6) Incomplete combustion of methane can occur in gas heaters such as the one
shown in the photograph.
Explain how incomplete combustion occurs and the problems it can cause.
Production
• lack of / insufficient oxygen
• {blocked burner jets / poor servicing} leads to lack of oxygen
• poor ventilation leads to lack of oxygen
• complete combustion cannot take place
Product
• produces carbon / soot
• produces carbon monoxide
Effects
• wastes fuel
• soot stains / damages decorations etc
• soot causes health problems
• soot may block gas jets
• carbon monoxide is toxic
• combines with haemoglobin / forms carboxyhaemoglobin
• prevents blood carrying oxygen
• no oxygen reaches cells / no respiration / death(1) For which fractions does the demand exceed the supply?
LPG, petrol and diesel
(2) Explain why cracking is needed.
use of {fractions / large molecules /
long chain hydrocarbons} of {less
demand / less useful / lower value}
/ ORA (1)
• to meet demand / small molecules
needed (1)(1) As the number of carbon atoms in the molecules of a hydrocarbon increases
the boiling point of the hydrocarbon
increases
(1) What is the formula of a molecule of ethene?
C2H4
(2) Ethene can be converted into poly(ethene).
Write a balanced equation for this reaction.
ignore n missing on polymer structure LHS (1) RHS (1) Allow: n (1) (where X could be CH3 or similar
(2) Explain why some people are concerned about the increase in the amount of
carbon dioxide in the atmosphere.
greenhouse gas / traps heat in
atmosphere (1)
• may lead to increasing global
temperature / global warming (1)
