Questions
Q1.
The table shows some properties of six compounds.
compound
melting point
/ °C
boiling point
/ °C
solubility in
water
copper sulfate
200
decomposes
soluble
hexane
–95
69
insoluble
hydrogen
chloride
–112
–85
soluble
electrical
conductivity
of solution
high
does not
dissolve
high
does not
dissolve
does not
silicon(IV) oxide 1610
2230
insoluble
dissolve
sodium chloride
801
1413
soluble
high
(a) Which of the following lists of compounds from the table contains only ionic compounds?
Put a cross (
) iin the box next to your answer.
octane
–57
126
insoluble
(1)
A copper sulfate, octane and sodium chloride
B silicon(IV) oxide and sodium chloride
C copper sulfate and sodium chloride
D copper sulfate and silicon(IV) oxide
(b) Two of the compounds in the table produce a colour in a flame test.
Give the name of one of these compounds and the colour it produces in the flame test.
(2)
compound . . . . . . . . . . . . . . . . . . . .
colour . . . . . . . . . . . . . . . . . . . .
(c) Hexane is a covalent compound containing simple molecules.
It has a low boiling point.
(i) Explain why it has a low boiling point.
(2)
(ii) Hexane and water are immiscible.
Describe how separate samples of hexane and water can be obtained from a mixture of hexane and
water.
(2)
(d) Draw a dot and cross diagram of a molecule of hydrogen chloride.
Show outer electrons only.
(2)
(Total for Question is 9 marks)
Q2.
Salts and analysis
(a) Which of the following pairs of substances contains one substance that is soluble in water and one
that is insoluble in water?
Put a cross (
) in the box next to your answer.
(1)
A
B
C
D
aluminium nitrate and lead sulfate
ammonium chloride and copper sulfate
copper hydroxide and lead sulfate
sodium hydroxide and potassium nitrate
(b) Barium chloride is an ionic compound and has a high melting point.
Explain why barium chloride has a high melting point.
(2)
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(c) Barium chloride solution is used to test for the presence of sulfate ions in a solution.
When sulfate ions are present, insoluble barium sulfate is formed.
(i) Describe the appearance of barium sulfate.
(1)
.............................................................................................................................................
(ii) Complete the balanced equation for the reaction between barium chloride and potassium sulfate.
(2)
BaCl2 + K2SO4 → ................................................................................................
(d) Compound X is a metal carbonate.
(i) A flame test was carried out on compound X.
A lilac flame was seen.
Complete the sentence by putting a cross ( ) in the box next to your answer.
(1)
The formula of the metal ion in compound X is
A Ca2+
B Cu2+
C K+
D Na+
(ii) Lead carbonate is an insoluble salt.
Describe how a pure, dry sample of solid lead carbonate can be obtained from sodium carbonate
solution and lead nitrate solution.
(3)
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(Total for question = 10 marks)
Q3.
Sodium carbonate and copper chloride are both ionic solids.
They are both soluble in water.
(a) Which row of the table shows the most likely melting points of these two salts?
Put a cross (
) in the box next to your answer.
(1)
melting point / °C
%%%
sodium carbonate
copper chloride
%%%
17
498
A
851
9
B
851
498
C
9
17
D
2+
(b) Copper chloride contains copper ions, Cu , and chloride ions, Cl–.
Give the formula of copper chloride.
(1)
..............................................................................................................................................
(c) Complete the sentence by putting a cross (
) in the box next to your answer.
If a flame test is carried out on copper chloride, the colour in the flame is
(1)
A red-brown
B yellow
C lilac
D green-blue
(d) Describe how this apparatus can be used to show that sodium carbonate reacts with dilute acid to
form carbon dioxide.
(3)
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
(e) Copper carbonate is an insoluble salt.
Describe how you would use sodium carbonate and copper chloride to produce a pure, dry sample of
copper carbonate.
(3)
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
(Total for Question is 9 marks)
Mark Scheme
Q1.
Answer
(a)
(b)
(c)(i)
(c)(ii)
C : copper sulfate
and sodium chloride
copper sulfate (1)
blue-green (1) or
sodium chloride (1)
yellow (1) colour
mark consequential
on correct metal
(compound)
An explanation
linking weak
intermolecular
forces /weak forces
between molecules
(1)
little heat /
energy needed to
separate (molecules)
(1)
A description linking
use separating
funnel (1)
run off
lower layer / liquid /
OWTTE (1)
(d)
shared pair in
molecule (1)
rest of molecule
consequent on first
mark (1)
Acceptable
answers
Mark
(1)
allow blue or green
or greenblue
reject orange
and yellow-orange
(2)
bonds / attractions
in place of forces
intermolecular forces
between atoms /
bonds loses 1st
marking point any
answer in terms of
covalent or ionic
bonding scores zero
alternative
description of
separating funnel eg
funnel with a tap at
the bottom suitable
labelled diagram
burette allow layers
/ liquids to separate
ignore fractional
distillation
Allow a diagram
without labels for 2
marks
any
symbols shown must
be correct for the 2nd
mark allow any
combination of dots
and crosses for
electrons wrong
compound = zero
marks
(2)
(2)
(2)
Q2.
Q3.
Answer
(a)
(b)
C
CuCl2
(c)
(d)
D
A description
including the
following
 put/mix/react
(sodium) carbonate
and acid in (conical)
flask (1)
 put limewater in
test tube(1)
 (carbon dioxide
produced) turns lime
water
milky/cloudy/white
precipitate (1)
A description
including three of the
following
 make
solutions/dissolve/
mix/react solutions
(1)
 precipitate (of
copper carbonate)
(1)
 filter (1)
 wash (with
water) (1)
 leave to dry/dry
in oven/dry between
filter paper (1)
(e)
Acceptable
answers
ensure that 2 is
subscript at most half
the size of Cl and
cases are correct
ignore correct
charges reject an
overall charge
2 max if reactants
and limewater are in
the wrong vessels
with the correct test
marks can be
awarded for the first
two marking points
by labelling the
diagram "reactants"
for sodium carbonate
and acid
max 2 marks if clear
error in process, e.g.
heat/add
acid/evaporate
ignore colours of
precipitate accepts
forms a solid for
precipitate
Mark
(1)
(1)
(1)
(3)
(3)