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Some intercontinental jet airliners use kerosene as fuel. The formula of kerosene may be taken as $C_{14}H_{30}$.
(a) To which homologous series of compounds does kerosene belong?
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(b) When kerosene burns in an excess of air, carbon dioxide and water form.
Balance the following equation for the complete combustion of kerosene.
...... $C_{14}H_{30}$(l) + ......$O_2$(g) $\rightarrow$ ......$CO_2$(g) + ......$H_2O$(g) [1]
(c) In this section, give your answers to one decimal place.
The flight path from Beijing to Paris is approximately 8195 km.
A typical intercontinental jet airliner burns 10.8 kg of kerosene for each kilometre covered.
(i) Calculate the mass, in tonnes, of $C_{14}H_{30}$ burnt on a flight from Beijing to Paris.
[1 tonne = 1000 kg] [2]
(ii) Use your equation in (b) to calculate the mass, in tonnes, of $CO_2$ produced during this flight. [4]
Bicycles may be carried on commercial airliners. When carried on airliners, bicycles are placed in the luggage hold. This is a part of the aircraft which, in flight, will have different temperatures and air pressures from those at sea level.
This question concerns the change in pressure in an inflated bicycle tyre from when it is at sea level to when it is in the hold of an airliner in flight.
(d) At sea level and a temperature of 20°C an inflated bicycle tyre contains 710 $cm^3$ of air at an internal pressure of $6 \times 10^5$ Pa.
Use the general gas equation $PV = nRT$ to calculate the amount, in moles, of air in the tyre at sea level. [2]
The same bicycle, with its tyres inflated at sea level as described in (d) above, is placed in the luggage hold of an airliner. At a height of 10 000 m, the temperature in the luggage hold is 5°C and the air pressure is $2.8 \times 10^4$ Pa.
(e) Assuming the volume of the tyre does not change, use your answer to (d) to calculate the pressure inside the tyre at a height of 10 000 m. [2]
568
580
586
(a) (i) What is meant by the term `cracking` and why is it carried out?
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(ii) Outline briefly how the cracking of hydrocarbons would be carried out.
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(iii) Construct a balanced equation for the formation of heptane, $C_7H_{16}$, by cracking tetradecane, $C_{14}H_{30}$.
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[4]
(b) The boiling point of ethanol, $C_2H_5OH$, is higher than that of $C_2H_5SH$.
Suggest a reason for this difference.
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[1]
(c) (i) Construct a balanced equation for this reaction.
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(ii) Two of the oxides formed cause serious environmental damage.
For each of these oxides, identify the type of pollution caused and describe one consequence of this pollution.
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[6]
(d) A small amount of ethanethiol is added to liquefied gases such as butane that are widely used in portable cooking stoves.
Suggest a reason for this.
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[1]
(e) State the main operating details of the formation of $SO_3$ in the Contact process.
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[3]
544
519
521
(a) State the formula of each of the calcium compounds U to Y.
- U
- V
- W
- X
- Y
(b) Compound Y may be converted into compound V.
Outline how this reaction would be carried out in a school or college laboratory using a small sample of Y.
(c) (i) Construct balanced equations for the following reactions.
- calcium to compound U
- compound V to compound W
- compound U to compound Y
(ii) Construct a balanced equation for the effect of heat on solid compound W.
(d) Suggest the formula of an aqueous reagent, other than an acid, for reaction 1.
(e) What would be observed when each of the following reactions is carried out in a test-tube?
the formation of X from Ca(s)
the formation of X from V
515
524
530
Ketones are widely used as solvents and as intermediates in the chemical industry.
Ketones contain the reactive keto group, $\text{C=O}$.
(a) Propanone, $\text{CH}_3\text{COCH}_3$, undergoes a reaction with hydrogen cyanide, HCN.
(i) What type of reaction is this?
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(ii) What reagents are used?
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(iii) Draw a diagram to show the dipole present in the propanone molecule.
(b) Propanone reacts with 2,4-dinitrophenylhydrazine reagent.
(i) Construct a balanced equation for the reaction between propanone and 2,4-dinitrophenylhydrazine.
(ii) A similar type of reaction occurs between propanone and hydroxylamine, $\text{NH}_2\text{OH}$.
Draw the displayed formula of the organic product of this reaction.
528
525
519
(a) When calcium carbide is reacted with water, ethyne and calcium hydroxide are formed.
Construct a balanced equation for this reaction.
(b) (i) What types of reaction are step 1 and step 2?
(ii) Suggest what reagent and conditions would be used in a laboratory in step 2.
(c) (i) Give the structural formulae of Q and R.
(ii) What type of reaction is step 3 and step 4?
(d) The standard enthalpy change of combustion of $C_2H_2$, $\Delta H^o_c$, is $−1300 \text{kJ mol}^{-1}$ at 298 K.
Values of relevant standard enthalpy changes of formation, $\Delta H^o_f$, measured at 298 K, are given in the table.
(i) Write balanced equations, with state symbols, that represent
the standard enthalpy change of combustion, $\Delta H^o_c$, of $C_2H_2$, and
the standard enthalpy change of formation, $\Delta H^o_f$, of $C_2H_2$.
(ii) Use the data above and your answer to (i) to calculate the standard enthalpy change of formation, $\Delta H^o_f$, of $C_2H_2$.
Show clearly whether the standard enthalpy change of formation of $C_2H_2$ has a positive or negative value.
595
551
538
