Chemistry Reference
In-Depth Information
(iii)
State the name of the central part of the
atom, labelled
X
. [1]
(iii)
Which statement about helium and argon
is correct? Tick
one
box.
22
Hydrogen chloride can be made by burning
hydrogen in chlorine.
a
Complete the equation for this reaction.
H
2
+ ______ → ______ HC
l
[2]
b
Draw a dot and cross diagram for a molecule of
hydrogen chloride. Show all the electrons.
Use
o
for an electron from a hydrogen atom.
Use
x
for an electron from a chlorine atom.
[2]
c
Hydrochloric acid is formed when hydrogen
chloride gas dissolves in water. Suggest the pH
of hydrochloric acid. Put a ring around the
correct answer.
pH 1
pH 7
pH 9
pH 13
Argon has an incomplete inner shell of
electrons.
An atom of argon has 16 electrons.
Helium has a complete outer shell of
electrons.
Helium has an incomplete outer shell of
electrons.
[1]
[1]
(iii)
How many protons are there in an atom of
argon?
d
Complete the equation for the reaction of
hydrochloric acid with zinc.
zinc + hydrochloric acid → zinc chloride + ______
[1]
(iv)
The symbol for a particular isotope of
helium is written as
2
He.
Write a similar symbol for the isotope of
argon which has 16 neutrons. [1]
c
Argon is a liquid at a temperature of −188 ºC.
Complete the diagram below to show how the
atoms of argon are arranged at −188 ºC.
represents one atom of argon.
[1]
e
Describe how dry crystals of zinc chloride
can be obtained from a solution of zinc
chloride.
[2]
f
A student electrolysed molten zinc chloride.
State the name of the product formed at:
(iii)
the anode,
[1]
(iii)
the cathode.
[1]
[Total: 10]
(Cambridge IGCSE Chemistry 0620 Paper 02
Q7 June 2009)
23
Sulfuric acid is a typical strong acid.
a
Change the equations given into a different
format.
(iii)
Mg + H
2
SO
4
→ MgSO
4
+ H
2
Change into a word equation.
[1]
[2]
(iii)
lithium oxide + sulfuric acid →
lithium sulfate + water
Change into a symbol equation.
[Total: 7]
(Cambridge IGCSE Chemistry 0620 Paper 21
Q3 November 2010)
[2]
(iii)
CuO + 2H
+
→ Cu
2+
+ H
2
O
Change the ionic equation into a symbol
equation. [2]
(iv)
Na
2
CO
3
+ H
2
SO
4
→ Na
2
SO
4
+ CO
2
+ H
2
O
Change into a word equation.
[1]
b
When sulfuric acid dissolves in water, the
following reaction occurs.
H
2
SO
4
+ H
2
O → HSO
4
−
+ H
3
O
+
Explain why water is behaving as a base in this
reaction.
[2]
