Higher Chemistry
Unit 1
Section 2 Enthalpy
Multiple Choice Questions
This is designed to be used by teachers to help students develop
skills in answering multiple choice questions.
Douglas Racey, Waid Academy, Anstruther, Fife, Scotland
Higher Chemistry
1.
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
The potential energy diagram for the reaction
CO(g) + NO2(g)  CO2 (g) + NO(g)
is shown.
DH, in kJmol-1, for the forward reaction is
A. -361
B. -227
C. -93
D. +361
Answer
A.
Higher Chemistry
2.
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
The enthalpy of neutralisation in an
acid/alkali reaction is always the energy
released in
A.
B.
C.
D.
the neutralisation of one mole of acid
the neutralisation of one mole of alkali
the formation of one mole of water
the formation of one mole of salt
Answer
D.
Higher Chemistry
3.
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
Ethanol (C2H5OH) has a different enthalpy
of combustion from diethyl ether
(CH3OCH3) because the compounds have
different
A.
B.
C.
D.
molecular masses
bonds within the molecules
products of combustion
boiling points
Answer
B.
Higher Chemistry
4.
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
Which of the following represents an
exothermic change?
A.
B.
C.
D.
O2(g)
CH4(g)
2N(g)
H2O(g)
Answer




2O(g)
C(g) + 4H(g)
N2(g)
2H(g) + O(g)
C.
Higher Chemistry
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
5.
The enthalpy change for the forward
reaction can be represented by
A.
x
B.
y
C.
x+y
D.
x-y
Answer
D.
Higher Chemistry
6.
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
The enthalpy of combustion of methanol is -715 kJ
mol-1.
The mass of methanol which has to be burned to
produce 71.5 kJ is
B.
3.2g
32g
C.
71.5g
D.
715g
A.
Answer
A.
Higher Chemistry
7.
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
A group of students added 6 g of ammonium chloride
crystals to 200 cm3 of water at a temperature of 25oC.
The enthalpy of solution of ammonium chloride is +13.6 kJ
mol-1.
After dissolving the crystals, the temperature of the
solution would most likely be
A.
B.
C.
D.
30oC
27oC
26oC
23oC
Answer
D.
Higher Chemistry
8.
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
Which equation illustrates an enthalpy of
combustion?
A.
B.
C.
C2H5OH + O2  CH3COOH + H2O
CH3CHO + ½ O2  CH3COOH
C2H6 + 3 ½ O2  2CO2 + 3H2O
D.
CH4 + 1 ½ O2  CO + 2H2O
Answer
C.
Higher Chemistry
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
9. When 3.6 g of butanal (relative formula mass = 72) was
burned, 134 kJ of energy was released.
From this result, what is the enthalpy of combustion, in
kJ mol-1?
A.
B.
C.
D.
Answer
-6.7
+6.7
-2680
+2680
C.
Higher Chemistry
Unit 2 - Section 2 Enthalpy
Multiple Choice Questions
10. The activation energy for the forward reaction
shown in the diagram below can be represented
by
A.
B.
C.
D.
Answer
x
y
x+y
x-y
A.