AS Level Chemistry A
H032/02 Depth in Chemistry
Friday 9 June 2017 – Afternoon
Time allowed: 1 hour 30 minutes
You must have: • the Data Sheet for
... [Show More] Chemistry A
(sent with general stationery) You may use: • a scientific or graphical calculator
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Answer all the questions.
1 Barium combines with oxygen, chlorine and nitrogen to form ionic compounds.
(a) Barium oxide, BaO, has a giant ionic lattice structure.
(i) State what is meant by the term ionic bond.
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(ii) Draw a ‘dot-and-cross’ diagram to show the bonding in barium oxide.
Show outer electrons only.
[2]
(iii) Calculate the number of barium ions in 1.50 g of barium oxide.
Give your answer in standard form and to three significant figures.
number of barium ions = .......................................................... [2]
(b) Barium chloride, BaCl2
, is soluble in water.
(i) Compare the electrical conductivities of solid and aqueous barium chloride.
Explain your answer in terms of the particles involved.
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(ii) Describe the use of aqueous barium chloride in qualitative analysis.
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(iii) Hydrated barium chloride can be crystallised from solution.
Hydrated barium chloride has the formula BaCl2
•xH2O and a molar mass of 244.3 g mol −1
. Determine the value of x in the formula of BaCl2
•xH O. 2 Show your working.
x = .......................................................... [2]
(c) Barium nitride is formed when barium is heated with nitrogen.
(i) Complete the electron configuration of a nitride ion.
1s2
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(ii) Solid barium nitride is reacted with water, forming an alkaline solution A and an alkaline
gas B.
Identify A and B. Write an equation, including state symbols, for the reaction.
A......................................................................................................................................... B.........................................................................................................................................
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