1.Which statement about this reaction is correct?
2Fe(s) + 3CO
2
(g) -» Fe
2
O
3
(s) + 3CO(g)
∆H =
+26.6 kJ
A. 26.6 kJ of energy are released for every mole of Fe reacted
B. 26.6 kJ of energy are absorbed for every mole of Fe reacted
C. 53.2 kJ of energy are released for every mole of Fe reacted
D. 13.3 kJ of energy are absorbed for every mole of Fe reacted
2.
A sodium hydroxide solution is reacted with excess hydrochloric acid. What information is not needed to calculate the molar heat of neutralisation of sodium hydroxide?
A. The initial temperature of both solutions
B. The volumes of both solutions
C. The concentration of the hydrochloric acid solution
D. The maximum temperature of the mixture
3. 200 J of energy were given to a 10 g sample of copper. If the temperature of the copper increased by 50° C, what is the specific heat capacity of the copper?
A. 0.25 Jg
-1 °C -1
B. 0.40 Jg -1 °C -1
C. 2.5 Jg
-1 °C -1
D. 4.0 Jg
-1 °C -1

4. A sample of a metal is heated. Which of the following are needed to calculate the heat absorbed by the sample?
I.
The mass of the sample
II.
The density of the sample
III.
The specific heat capacity of the sample
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
5. What is the energy change (in kJ) when the temperature of 20 g of water increases by 10°C ?
A. 20 x 10 x 4.18
B. 20 x 283 x 4.18
C. 20 x 10 x 4.18
1000
D. 20 x 283 x 4.18
1000
6. Which statements about exothermic reactions are correct?
I.
They have negative ∆H values.
II.
The products have a lower enthalpy than the reactants.
III. The products are more energetically stable than the reactants.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
7. Separate solutions of HCl(aq) and H
2
S0
4
(aq) of the same concentration and same volume were completely neutralized by NaOH (aq). XkJ and YkJ of heat were evolved respectively. Which statement is correct?
A. X=Y
B. Y=2X
C. X=2Y
D. Y=3X

8. If 3600 J of heat is added to 180 g of C
2
H
5
OH(l), its temperature increases from 18.5 0 C to 28.5
0 C
What is the specific heat capacity of C
2
H
5
OH(l) ?
A..
0.500 Jg
-1 °C -1
B.
2.00 Jg
-1 °C -1
C. 20.0 Jg
-1 °C -1
D. 200 Jg -1 °C -1
9. (i) 10.0 g of solid NaOH is added to 100 g of water at 23.2°C in a glass beaker. The solution is stirred and a maximum temperature of 44.6 °C is reached. Calculate the heat produced by the reaction. (Assume the specific heat capacity of the solution is 4.20 Jg
-1 °C -1
.) [3]
(ii) Calculate the enthalpy change for dissolving solid NaOH in water in kJ mol -1 .
[1]
(iii) The value given in the literature under similar conditions is -42.7 kJmol -1 . Suggest a reason why the calculated value of the enthalpy change of solution is different from the literature value and propose an improvement in the procedure to obtain a more accurate value.
[2]

1. Consider the following reaction:
N
2
(g) + 3H
2
(g)->2NH
3
(g) ∆H ө
=?
Bond enthalpies (in kJ mol
-1
) involved in the reaction are
Which calculation will give the value of
∆H ө
?
A. x + 3y-6z
B. 6z-x + 3y
C. x-3y + 6z
D. x + 3y~2z
O
2
3O
(g) -> 2O(g)
2
(g)->2O
3
(g)
∆H =
498 kJ
∆H
= 284kJ
2. Using the information above, what is
∆H
for the following equation in kJ?
O
3
(g)->3O(g)
A. 214
B. 56
C. 463
D. 605
3. Consider the following reactions:
CH
3
COOH + OH
-
-> CH
3
COO
-
+ H
2
O
H
+
+OH
-
->H
2
O
What is the enthalpy change for the reaction below?
CH
3
COOH -> CH
3
COO
-
+ H
+
A. q
2
-q,
B. q
1
-q
2
C. -q
1
-q
2
D. 2q
2
–q
1
∆H ө
= q
1
kJ
∆H ө
=q
2 kJ

2HCl(aq) + 2KHCO
3
(s) ------------- ► K
2
CO
3
(s) + CO
2
(g) + H
2
O(l)
ΔH
1
ΔH
2
+2HCl(aq)
2KCl(aq) + 2CO
2
(g) + 2H
2
O(l)
4.
This cycle may be used to determine ΔH for the decomposition of potassium hydrogencarbonate. Which expression can be used to calculate ΔH ?
A.
ΔH
=
ΔH
1
+ ΔH
2
B.
ΔH
=
ΔH
1
- AH
2
C.
ΔH
= ½
ΔH l
-
ΔH
2
D.
ΔH = ΔH
2
– ΔH
1
5. The bond enthalpies in kJ mol
-1
for several bonds are given below:
H—H 436 O—O 196 O=O 496
What is the enthalpy change, ΔH , in kJ for the reaction below?
H—O 463
2H
2
(g)+0
2
(g)->2H
2
0(g)
A. 442
B. 92
C. -484
D. -834
6.
The bond enthalpies for H
2
, Br
2
, and HBr are 436, 193 and 368 kJ mol
-1 respectively. Calculate ΔH of the reaction
H
2
+Br
2
->2HBr
A. -261
B. -107
C. +107
D. +261

7 . The average bond enthalpies for O-O and O=O are 146 and 496 kJ mol -1 respectively. What is the enthalpy change, in kJ, for the reaction below?
H-O-O-H(g) ----► H-O-H(g) + ½ O=O(g)
A. -102
B. +102
C. + 350
D. + 394
8.(a) Define the term average bond enthalpy, illustrating your answer with an equation for methane, CH
4
.
[3]
(b) The equation for the reaction between methane and chlorine is
CH
4
(g) + Cl
2
(g) -> CH
3
Cl(g) + HCl(g)
Use the values from Table 10 of the Data Booklet to calculate the enthalpy change for this reaction.
[3]
(c.) Draw an enthalpy level diagram for this reaction.
[2]

9 (a) Hess's law states that, whether a reaction occurs in one or several steps, the total enthalpy change is the same. Illustrate your understanding of this law by using the data below to calculate the enthalpy change (
ΔH
) when one mole of solid carbon is converted into carbon monoxide.
[3]
C(s) + O
2
(g) ->CO
2
(g) ΔH = -393.5 kJ
CO(g) + ½ O
2
(g) ->CO
2
(g) ΔH = -283.0 kJ
(b) State what is meant by the term endothermic reaction
10. (a) Define average bond enthalpy.
(b) Using the following average bond enthalpies (kJ mol
-1
);
C-H 412, O=O 496, C=O 743, O-H 463 calculate the enthalpy change for the following reaction:
CH
4
(g) + 2O
2
(g)->CO
2
(g) + 2H
2
O(g)
[1]
[2]
[3]

11. Enthalpy changes may also be calculated by using bond enthalpies, some values of which
(kJmol
-1
) are provided below:
C = C 612; C—H 412; O—H463; C = O 743; O = O 496.
The balanced equation for the complete combustion of one mole of ethene, C
2
H
4
, in oxygen ;
Is shown below:
C
2
H
4
+ 3O
2
-> 2CO
2
+ 2H
2
O
(i) Use the equation and the bond enthalpy data above to calculate the enthalpy change for the complete combustion of one mole of ethene.
[4]
(ii) State, with a brief explanation, whether the reaction is endothermic or exothermic.
[1]

1. Which of the changes below occurs with the greatest increase in entropy?
A. Na
2
O(s) + H
2
O(l)->2Na + (aq) + 2OH (aq)
B. NH
3
(g) + HCl(g) ->NH
4
Cl(s)
C. H
2
(g)+I
2
(g) ->2HI(g)
D. C(s) + CO
2
(g)->2CO(g)
2. Which of the following reactions has/have a decrease in entropy in the forward direction?
I. HCl(g) +NH
3
(g) -> NH
4
Cl(s)
II. CaCO
3
(s) -> CaO(s) + CO
2
(g)
Mg(s) + 2HCl(aq) ->MgCl
2
(aq) + H
2
(g) III.
A. I only
B. II only
C. I and III only
D. II and III only
3. Ammonium nitrate, NH
4
NO
3
, dissolves readily in water according to the equation:
NH
4
NO
3
(s)-> NH
4
+ (aq) + NO
3
(aq) ΔH = 28 kJ mol -1
Which of the following contribute(s) to the occurrence of this process?
I. The system moves to lower enthalpy. .
II. The system becomes more disordered.
A. I only
B. II only
C. Both I and II
D. Neither I nor II

4.
A certain reaction is spontaneous at low temperatures but becomes non-spontaneous as the temperature is raised. Based on this information, what are the signs of ΔH and Δ S?
Δ H Δ S
A. + +
B.
C.
D.
+
-
-
-
+
-
5.The following reaction takes place in an internal combustion engine:
2C
8
H
18
(g) + 25O
2
(g)->16CO
2
(g) + 18H
2
O(g)
What are the signs for Δ H
θ
, Δ S
θ and Δ G
θ
for this reaction?
A.
B.
C.
D.
Δ H
θ
-
-
-
+
Δ S
θ
+
+
-
-
Δ G
θ
+
-
-
-
6. Which reaction has the greatest positive entropy change?
A. CH
4
(g) + 1½ O
2
(g) -> CO(g) + 2H
2
O(g)
B. CH
4
(g) + 1½ O
2
(g) -> CO(g) + 2H
2
O(l)
C. CH
4
(g) + 2O
2
(g) -> CO
2
(g) + 2H
2
O(g)
D. CH
4
(g) + 2O
2
(g)->CO
2
(g) + 2H
2
O(l)
7.
Which reaction has a positive entropy change, Δ S
θ
?
A. H
2
O(g) -> H
2
O(l)
B. 2SO
2
(g) + O
2
(g) -> H
2
SO
3
(g)
C. CaCO
3
(s)->CaO(s)+CO
2
(g)
D. N
2
(g)+3H
2
(g) ->2NH
3
(g)

8. The enthalpy diagram for a reaction between two aqueous solutions at room temperature is shown * below.
(a) (i) Give the sign of Δ H for this reaction and indicate whether it is endothermic or exothermic. State the relative strengths of the bonds in the products and reactants.
[3]
(ii) This reaction is spontaneous at room temperature. Use this information along with that in (i) to give the signs of Δ G
θ
and Δ S
θ
, outlining your reasoning in each case.
Comment on the meaning of the sign of Δ S
θ in terms of the relative disorder of the reactants and products.
[5]

(iii) Describe an experiment that could be conducted in a school laboratory to determine the value of Δ H (in kJmol
-1
) for this reaction. Show the calculations that would need to be carried out to obtain the value of Δ H.
[6]
(iv) Outline two sources of error in the experimental procedure that could result in a calculated Δ H value that is smaller than the accepted value and suggest a way that one of these could be minimised.
[3]
(v) Discuss how the spontaneity of this reaction would change as the temperature is increased from room temperature, and also as the temperature is decreased from room temperature. Outline your reasoning in each case.
[3]

1. Consider the following equations:
S(s) + O
2
(g)→SO
2
(g)
SO
2
(g) + ½ O
2
(g) →SO
3
(g)
SO
3
(g) + H
2
O(1) →H
2
SO
4
(1)
H
2
(g)+ ½ O
2
(g) →H
2
O(l)
Δ H
θ
= -298 kJ
Δ
H
θ
= -98 kJ
Δ
H
θ
= -130 kJ
Δ
H
θ
= -286 kJ
What is the standard enthalpy change of formation (Δ H
θ f
)for H
2
S0
4
(1)?
A. -812 kJ
B. +812 kJ
C. -526 kJ
D. +526 kJ
2. Excess thionyl chloride, SOCl
2
, can be removed from a reaction mixture by reacting it with water I'according to the equation;
SOCl
2
(l) + H
2
O(l) → 2HCl(g) + SO
2
(g)
Use the following data to calculate Δ H
θ for this reaction.
SOCl
2
(l) H
2
O(1) HCl(g) SO
2
(g)
Δ H
θ f
-1
-245,6 -285.8
-92.3
-296.8
A.
-142.3
B.
-50.0
C.
+50.0
D.
+142.3

3. Which substance has the largest lattice energy?
A. NaF
B. KC1
C. MgO
D. CaS
4. The lattice enthalpy values for lithium fluoride and calcium fluoride are shown below.
LiF(s) Δ H
θ
= +1022 kJ mol -1 CaF
2
(s)
Δ H
θ
= +2602 kJ mol
-1
Which of the following statements help(s) to explain why the value for lithium fluoride is less than that for calcium fluoride?
I The ionic radius of lithium is less than that of calcium.
II. The ionic charge of lithium is less than that of calcium.
A. I only
B. II only
C. I and II
D. Neither I nor II
5. The following enthalpy changes (in kJ mol
-1
) refer to sodium chloride and its constituent elements.
Δ
H
θ fonnation
Δ
H
θ
atomisation
Δ
H
θ atomisation sodium chloride sodium chlorine
1st ionisation energy
1st electron affinity sodium chlorine
-411
+109
+121
+494
-364
(a) (i) State the meaning of the + and -signs in the enthalpy values.
[1]
(ii) Explain the meaning of the symbol
θ
.
[1]

(b) Write an equation, including state symbols, for each of the above enthalpy changes.
(c) The given values can be used to calculate the lattice enthalpy of sodium chloride.
(i) Define the term lattice enthalpy.
[1]
[5]
(ii) Construct a Born-Haber cycle and hence calculate the lattice enthalpy of sodium chloride. [4]
6. (a) Given the following data:
C(s)+2F
2
(g) → CF
4
(g); ΔH
1
, = -680kJmol
-1
F
2
(g) → 2F(g); ΔH
2
= +158kJ mol
-1
C(s) → C(g); ΔH
3
= +715 kJ mol
-1 calculate the average bond enthalpy (in kJ mol
-1
) for me C—F bond.
[4]

1. Which change leads to a decrease in entropy for the system?
A. Solid ammonium chloride sublimes.
B. Sodium corrodes in air.
C. Potassium nitrate dissolves in water.
D. Two inert gases mix at constant temperature and pressure.
2. How would this reaction at 298 K be described in thermodynamic terms?
2H
2
O(g) → 2H
2
(g) + O
2
(g)
A. Endothermic with a significant increase in entropy
B. Endothermic with a significant decrease in entropy
C. Exothermic with a significant increase in entropy
D. Exothermic with a significant decrease in entropy
3.The enthalpy change, Δ H
θ
,for a chemical reaction is –10 kJ mol -1 and the entropy change, Δ S
θ
is
–10 kJ mol -1 at 27 °C. What is the value of Δ
G
θ
(in J) for this reaction?
A. -260
B. -7000
C. -9730
D. -13000

4.
For the reaction;
Δ
H
θ
= -597.3 kJ and Δ
S
θ
= -0.33 kJ K
-1
. This reaction
A. is spontaneous at 300K and becomes non-spontaneous at higher temperatures.
B. is spontaneous at 300K and becomes non-spontaneous at lower temperatures.
C. is non-spontaneous at 300K and becomes spontaneous at higher temperatures.
D. is non-spontaneous at 300K and becomes spontaneous at lower temperatures.
5. When Δ G
θ for a reaction is negative, the reaction is
A. fast.
B. endothermic.
C. reversible.
D. spontaneous.
6.
Substance Standard Enthalpy of
Formation, Δ H
θ f
/ kJ mol
-1
Absolute Entropy,
/ Jmol
-1
K
-1
S
θ
. C(s) 0.0
5.7
CO
2
(g) -393.5
213.6
H
H
2
2
(g)
O(1)
0.0
-285.9
130.6
69.9
O
2
(g) 0.0
205.0
C
3
H
7
COOH(l) 226.3
The enthalpy change for the combustion of butanoic acid at 25° C is —2183.5kJmol
-1
.
The combustion reaction is:
,
C
3
H
7
COOH(l) +5O
2
(g) → 4CO
2
(g) + 4H
2
O(1)
(a) Write the balanced equation for the formation of butanoic acid from its elements.
[1]
(b) Using the above data, calculate the standard enthalpy of formation, Δ H
θ
, for butanoic acid.
[3]

(c) Calculate the standard entropy change, Δ
S
θ f
, for the formation of butanoic acid at 25
0
C.
[3]
(d) Calculate the standard free energy of formation, Δ G
θ f
, for butanoic acid at 25° C.
[2]
(e) Is this reaction spontaneous at 25 o
C? Explain your answer.
[1]
(f) For the process:
C
6
H
6
(l) → C
6
H
6
(s) the standard entropy and enthalpy changes are:
Δ H
θ
= -9.83 kJ mol
-1
and Δ S
θ
= -35.2 J K
1
mol
-1
Predict and explain the effect of an increase in temperature on the spontaneity of the process. [3]

7. The equation for the decomposition of calcium carbonate is given below.
CaCO
3
(s) → CaO(s) + CO
2
(g)
At 500 K, Δ H for this reaction is +177 kJ mol -1 and Δ S is +161J K -1 mol -1 .
(a) Explain why Δ H for the reaction above cannot be described as Δ H
θ f
.
[2]
(b) State the meaning of the term Δ S.
[]]
(c) Calculate the value of ΔG at 500 K and determine, giving a reason, whether or not the reaction will be spontaneous.
[3]
8.
(a) Explain in terms of ΔG
θ
, why a reaction for which both Δ H
θ and ΔS
θ
are positive is sometimes
[4 spontaneous and sometimes not
(b) Consider the following reaction.
N
2
(g) + 3H
2
(g) → 2NH3(g)
(i) Using the average bond enthalpy values in Table 10 of the Data Booklet, calculate the standard enthalpy change for this reaction.
[4]
(ii) The absolute entropy values, S, at 300 K for N
2
(g), H
2
(g) andNH
3
(g) are 193, 131 and 192
J K - 1 mol -1 respectively. Calculate ΔS
θ
for the reaction and explain the sign of ΔS θ
[3].
(iii) Calculate ΔG
θ
for the reaction at 300 K. [1]
(iv) If the ammonia were produced as a liquid and not as a gas, state and explain the effect this would have on the value of Δ H
θ
for the reaction.
[2]