AS Level Chemistry A
H032/02 Depth in chemistry
Sample Question Paper
Date – Morning/Afternoon
Time allowed: 1 hour 30 minutes
Specim
You must have:
the Data Sheet for Chemistry A
You may use:
a scientific calculator
* 0 0 0 0 0 0 *
First name
Last name
Centre
en
Candidate
number number
INSTRUCTIONS
• Use black ink. HB pencil may be used for graphs and diagrams only.
• Complete the boxes above with your name, centre number and candidate number.
• Answer all the questions.
• Write your answer to each question in the space provided.
• Additional paper may be used if required but you must clearly show
your candidate number, centre number and question number(s).
• Do not write in the bar codes.
INFORMATION
• The total mark for this paper is 70.
• The marks for each question are shown in brackets [ ].
• Quality of extended responses will be assessed in questions marked with an asterisk
(*).
• This document consists of 20 pages.
© OCR 2014 H032/02
[601/5256/4] DC (…) Turn over
, 2
Answer all the questions.
1 Bromine is a reactive element. It combines with other non-metals to form covalent compounds.
Phosphorus tribromide, PBr3, and iodine monobromide, IBr, are examples of covalent compounds used in
organic synthesis.
(a) PBr3 can be prepared by heating bromine with phosphorus, P4.
(i) Write an equation for this reaction.
…………………………………………………………………………………………. [1]
(ii) How many molecules are present in 1.3535 g of PBr3?
Specim
en number of molecules = ………………………
(iii) The ‘dot-and-cross’ diagram of a molecule of PBr3 is given below.
[3]
Name the shape of this molecule and explain why the molecule has this shape.
name: ………………………………………………………………………………………..
explanation: ………………………………………………………………………………….
……………………………………………………………………………………………….
……………………………………………………………………………………………….
[3]
© OCR 2014 H032/02
, 3
(b) Bromine reacts with iodine to form iodine monobromide, IBr.
The table below lists some average bond enthalpies which are required in different parts of this
question.
Bond Average bond enthalpy / kJ mol1
Br–Br +193
I–I +151
I–Br +175
(i) Average bond enthalpy is the enthalpy change for the breaking of 1 mole of bonds in
gaseous molecules.
Why do Br2 and I2 not exist in the gaseous state under standard conditions?
Specim
……………………………………………………………………………………………….
……………………………………………………………………………………….. [1]
(ii) Calculate the enthalpy change of formation, fH, for IBr.
en
fH =.......................................kJ mol1 [2]
(c) Iodine monobromide, I–Br, is a polar molecule.
Heterolytic fission of the I–Br bond forms an electrophile.
State the meaning of the term electrophile and suggest the formula of the electrophile formed from
IBr.
……………………………………………………………………………………………….
……………………………………………………………………………………….. [2]
(d) Bromine disproportionates when it reacts with potassium hydroxide solution.
Suggest an equation for this reaction.
……………………………………………………………………………………………… [1]
© OCR 2014 H032/02 Turn over
, 4
BLANK PAGE
Specim
en
© OCR 2014 H032/02
H032/02 Depth in chemistry
Sample Question Paper
Date – Morning/Afternoon
Time allowed: 1 hour 30 minutes
Specim
You must have:
the Data Sheet for Chemistry A
You may use:
a scientific calculator
* 0 0 0 0 0 0 *
First name
Last name
Centre
en
Candidate
number number
INSTRUCTIONS
• Use black ink. HB pencil may be used for graphs and diagrams only.
• Complete the boxes above with your name, centre number and candidate number.
• Answer all the questions.
• Write your answer to each question in the space provided.
• Additional paper may be used if required but you must clearly show
your candidate number, centre number and question number(s).
• Do not write in the bar codes.
INFORMATION
• The total mark for this paper is 70.
• The marks for each question are shown in brackets [ ].
• Quality of extended responses will be assessed in questions marked with an asterisk
(*).
• This document consists of 20 pages.
© OCR 2014 H032/02
[601/5256/4] DC (…) Turn over
, 2
Answer all the questions.
1 Bromine is a reactive element. It combines with other non-metals to form covalent compounds.
Phosphorus tribromide, PBr3, and iodine monobromide, IBr, are examples of covalent compounds used in
organic synthesis.
(a) PBr3 can be prepared by heating bromine with phosphorus, P4.
(i) Write an equation for this reaction.
…………………………………………………………………………………………. [1]
(ii) How many molecules are present in 1.3535 g of PBr3?
Specim
en number of molecules = ………………………
(iii) The ‘dot-and-cross’ diagram of a molecule of PBr3 is given below.
[3]
Name the shape of this molecule and explain why the molecule has this shape.
name: ………………………………………………………………………………………..
explanation: ………………………………………………………………………………….
……………………………………………………………………………………………….
……………………………………………………………………………………………….
[3]
© OCR 2014 H032/02
, 3
(b) Bromine reacts with iodine to form iodine monobromide, IBr.
The table below lists some average bond enthalpies which are required in different parts of this
question.
Bond Average bond enthalpy / kJ mol1
Br–Br +193
I–I +151
I–Br +175
(i) Average bond enthalpy is the enthalpy change for the breaking of 1 mole of bonds in
gaseous molecules.
Why do Br2 and I2 not exist in the gaseous state under standard conditions?
Specim
……………………………………………………………………………………………….
……………………………………………………………………………………….. [1]
(ii) Calculate the enthalpy change of formation, fH, for IBr.
en
fH =.......................................kJ mol1 [2]
(c) Iodine monobromide, I–Br, is a polar molecule.
Heterolytic fission of the I–Br bond forms an electrophile.
State the meaning of the term electrophile and suggest the formula of the electrophile formed from
IBr.
……………………………………………………………………………………………….
……………………………………………………………………………………….. [2]
(d) Bromine disproportionates when it reacts with potassium hydroxide solution.
Suggest an equation for this reaction.
……………………………………………………………………………………………… [1]
© OCR 2014 H032/02 Turn over
, 4
BLANK PAGE
Specim
en
© OCR 2014 H032/02
