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 ...
1 bromine is a reactive element it combines with other non metals to form covalent compounds phosphorus tribromide
are examples of covalent compounds used in orga
Written for
AS Level Chemistry A
All documents for this subject (29)
Seller
Follow
teachertestbank
Reviews received
Content preview
Chemistry
PMT
AS Level Chemistry A
H032/02 Depth in chemistry
Sample Question Paper
Date – Morning/Afternoon
Time allowed: 1 hour 30 minutes
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 number Candidate 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.
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?
number of molecules =.......................................... [3]
(iii) The ‘dot-and-cross’ diagram of a molecule of PBr3 is given below.
Name the shape of this molecule and explain why the molecule has this shape.
name: ………………………………………………………………………………………..
explanation: ………………………………………………………………………………….
……………………………………………………………………………………………….
……………………………………………………………………………………………….
[3]
Chemistry H032/02
, PMT
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?
……………………………………………………………………………………………….
……………………………………………………………………………………….. [1]
(ii) Calculate the enthalpy change of formation, fH, for IBr.
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.
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller teachertestbank. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.49. You're not tied to anything after your purchase.
