A student mixed 30.0 cm3 of 0.0250 mol dm-3 potassium hydroxide solution with 30.0 cm3 of 0.0250 mol dm-3 nitric acid. The temperature rose by 0.50 oC. Assume no heat was lost to the surroundings.
The mixture had a specific heat capacity of 4.18 J g -1 K-1.
What is the molar enthalpy change for the reaction?
Question 2
Marks: 1
An experiment was carried out to determine the approximate value for the molar enthalpy change of neutralisation.
75 cm3 of 3.00 mol dm–3 hydrochloric acid was placed in a polystyrene beaker of negligible heat capacity. Its temperature was recorded, and then 75 cm3 of 3.00 mol dm−3 potassium hydroxide at the same temperature was quickly added, and the solution stirred.
The temperature rose by 14 °C. The resulting solution may be considered to have a specific heat capacity of 4.18 J g-1 K-1.
Which calculation below is correct?
J mol-1
J mol-1
J mol-1
J mol-1
Question 3
Marks: 1
The table below discusses three types of enthalpy change:
‘+’ means that this type of standard enthalpy change can only have positive values,
‘–’ means that this type of standard enthalpy change can only have negative values,
‘+ / –’ means that either positive or negative values are possible.
Which row is correct?
formation
combustion
neutralisation
A
+
+
+ / –
B
+ / –
+
+ / –
C
+ / –
–
–
D
–
–
+
Question 4
Marks: 1
Using a spirit burner, ethanol is used to heat a container of water.
In this experiment:
Mass of ethanol burned, g
a
Mass of water, g
b
Specific heat capacity of water, J g–1 K–1
d
Temperature rise, °C
y
How much heat energy is absorbed by the water?
ady
bdy
bd(y+273)
(y+273) / ad
Question 5
Marks: 1
An iron block with a mass of 0.11 kg absorbs 504 J of heat energy. What is the temperature rise in K?
Specific heat capacity of iron = 0.448 J g–1 K–1
1.02 x104
1.10
10.23
9.78 x 10-2
Question 6
Marks: 1
Which statements are correct for an endothermic reaction?
The products are more stable than the reactants
The enthalpy change is positive
The temperature of the surroundings decreases
I and II only
I and III only
II and III only
I, II and III
Question 7
Marks: 1
Which assumptions are correct when calculating the enthalpy change for a reaction in solution?
The density of the solution is 1 g cm-3
The specific heat capacity of the solution is 4.18 J g-1 K-1
The correct stoichiometric quantities of reactants for a complete reaction are used
I and II only
I and III only
II and III only
I, II and III
Question 8
Marks: 1
What is the closest integer value of the temperature change for this reaction, from the graph
8
9
11
35
Question 9
Marks: 1
Which enthalpy changes correctly describe the following reactions?
Reaction 1: HNO3 (aq) + NH3 (aq) → NH4NO3 (aq)
Reaction 2: CuCO3 (s) → CuO (s) + CO2 (g)
Reaction 3: S (s) + O2 (g) → SO2 (g)
ΔHӨc
ΔHӨf
ΔHӨneut
ΔHӨr
A
2
2
1
3
B
3
2
1
2
C
3
3
1
2
D
2
3
1
3
Question 10
Marks: 1
Which systems are correctly described?
Matter and energy can be transferred across the boundary of an open system
Only matter can be transferred across the boundary of a closed system
Matter and energy cannot be transferred across the boundary of an isolated system