Chemistry
1. (a) The diagram below represents the industrial fractional distillation of crude oil.
(i) Identify fraction A. (ii) What property of the fractions allows them to be separated in the column? (2)
(b) A gas oil fraction from the distillation of crude oil contains hydrocarbons in the C15 to C19 range. These hydrocarbons can be cracked by strong heating.
(i) Write the molecular formula for the alkane with 19 carbon atoms. (ii) Name the type of reaction involved in cracking. (iii) Write an equation for one possible cracking reaction of the alkane C16H34 when the products include ethene and propene in the molar ratio 2:1 and only one other compound. (4)
(Total 6 marks)
2. A compound of carbon, hydrogen and nitrogen contains 61.0% of carbon and 15.3% of hydrogen by mass.
(i) Calculate the empirical formula of the compound. (ii) What other piece of data is required to deduce the molecular formula from the empirical formula? (iii) If the molecular formula of the compound is the same as the empirical formula, draw two possible structures of the compound. (Total 6 marks)
3. (a) Compound A (Mr = 215.8) contains 22.24% carbon, 3.71% hydrogen and 74.05% bromine by mass. Show that the molecular formula of A is C4H8Br2. (3) (b) There are nine structural isomers of molecular formula C4H8Br2, three of which have branched carbon chains. Give the names and draw the displayed formulae for any two of the branched chain isomers of C4H8Br2. (4) (Total 8 marks)
4. The table below shows the fractions obtained from crude oil.
Name of fraction
Number of carbon atoms
Use
Gases
1-4
bottled fuels for camping
Petrol (gasoline)
4-12
fuel for cars
Naphtha
7-14
11-15 jet fuel
Gas oil (diesel)
15-19
central heating fuel
Mineral oil
20-30
lubrication
Fuel oil
30-40
Wax
41-50
candles
Bitumen
over 50 road surfacing (a) Complete the table above by writing in the empty boxes
(3)
(b) Give one structural formula in each case for
(i) Identify fraction A. (ii) What property of the fractions allows them to be separated in the column? (2)
(b) A gas oil fraction from the distillation of crude oil contains hydrocarbons in the C15 to C19 range. These hydrocarbons can be cracked by strong heating.
(i) Write the molecular formula for the alkane with 19 carbon atoms. (ii) Name the type of reaction involved in cracking. (iii) Write an equation for one possible cracking reaction of the alkane C16H34 when the products include ethene and propene in the molar ratio 2:1 and only one other compound. (4)
(Total 6 marks)
2. A compound of carbon, hydrogen and nitrogen contains 61.0% of carbon and 15.3% of hydrogen by mass.
(i) Calculate the empirical formula of the compound. (ii) What other piece of data is required to deduce the molecular formula from the empirical formula? (iii) If the molecular formula of the compound is the same as the empirical formula, draw two possible structures of the compound. (Total 6 marks)
3. (a) Compound A (Mr = 215.8) contains 22.24% carbon, 3.71% hydrogen and 74.05% bromine by mass. Show that the molecular formula of A is C4H8Br2. (3) (b) There are nine structural isomers of molecular formula C4H8Br2, three of which have branched carbon chains. Give the names and draw the displayed formulae for any two of the branched chain isomers of C4H8Br2. (4) (Total 8 marks)
4. The table below shows the fractions obtained from crude oil.
Name of fraction
Number of carbon atoms
Use
Gases
1-4
bottled fuels for camping
Petrol (gasoline)
4-12
fuel for cars
Naphtha
7-14
11-15 jet fuel
Gas oil (diesel)
15-19
central heating fuel
Mineral oil
20-30
lubrication
Fuel oil
30-40
Wax
41-50
candles
Bitumen
over 50 road surfacing (a) Complete the table above by writing in the empty boxes
(3)
(b) Give one structural formula in each case for