would be more likely to maintain its heat and keep you warm through a

thomas (tt9669) – Post-lab 2 Enthalpy – lyon – (51730)
This print-out should have 15 questions.
Multiple-choice questions may continue on
the next column or page – find all choices
before answering.
001 10.0 points
A 100 g sample of an unknown liquid absorbs
2000 J of heat energy, raising the liquid’s
temperature from 50◦ C to 70◦ C .
What is the specific heat capacity of this
liquid? No phase change took place.

1

5. O2 (g), H2 (g)
004 10.0 points
Consider the following specific heats: copper,
0.384 J/g·◦ C; lead, 0.159 J/g·◦ C; water, 4.18
J/g·◦ C; glass, 0.502 J/g·◦ C. Which substance,
once warmed, would be more likely to maintain its heat and keep you warm through a
long football game on a cold night?
1. lead

1. 2.5 J/g · C
2. water
2. 1 J/g · C
3. glass
3. 4000 kJ/g · C
4. copper
4. 0.3 J/g · C
005 10.0 points
Calculate the standard reaction enthalpy for
the reaction.

5. 4.8 J/g · C
002 10.0 points
In calculating the heat given off by a reaction
in a calorimeter, you must account for heat
absorbed by
1. the calorimeter only.
2. water and the calorimeter.
3. air only.
4. water only.
003

CH4 (g) + H2 O(g) → CO(g) + 3 H2(g)
given
2 H2 (g) + CO(g) → CH3 OH( )
∆H ◦ = −128.3 kJ · mol−1
2 CH4 (g) + O2 (g) → 2 CH3 OH( )
∆H ◦ = −328.1 kJ · mol−1
2 H2 (g) + O2 (g) → 2 H2 O(g)
∆H ◦ = −483.6 kJ · mol−1
1. +155.5 kJ · mol−1

10.0 points

Which of

2. +216 kJ · mol−1

O2 (g), O2 ( ), H2 (g), H2 ( ), H2 O(g), H2 O( )

3. +206.1 kJ · mol−1

have a heat of formation equal to zero?

4. +412.1 kJ · mol−1

1. All of them, but only at absolute zero
2. O2 (g), H2 (g), H2 O(g)
3. O2 (g), O2 ( ), H2 (g), H2 ( ), H2 O(g),
H2 O( )
4. O2 (g), O2 ( ), H2 (g), H2 ( )

5. +42.0 kJ · mol−1
006 10.0 points
A 588 g chunk of iron is heated to 97.5◦C.
Then it is immersed in 247 mL of water originally at 20.7◦C. When thermal equilibrium
has been reached, the water and the iron are
both at 36.2◦C. Calculate the specific heat of

thomas (tt9669) – Post-lab 2 Enthalpy – lyon – (51730)
the iron. Assume no heat loss to the calorimeter and the density of water is 1.00 g/mL. The
specific heat capacity of water is 4.184 J/g·◦ C.

2

6. Ccal = −11.97 calories/K; no
009

10.0 points

1. 0.853 J/g·◦ C
2. 0.678 J/g·◦ C
3. 0.444 J/g·◦ C
4. 1.17 J/g·◦ C
007 10.0 points
Which compound has the smallest specific
heat capacity (in J/g·◦ C)?
1. water
2. ice
3. air
4. copper metal
008 10.0 points
You just received a new bomb calorimeter.
The factory calibration states that the heat
capacity of the calorimeter itself is 50 J/K
(Ccal = 50 J/K). You decide to check for yourself what Ccal is; you fill the calorimeter with
2 L of water, and detonate 1 g of sugar which
you know releases 4000 calories of heat. You
then measure a temperature change of 1.9881
K. What value of Ccal do you calculate for
your new calorimeter and is this value within
5 J/K of the factory value? The specific heat
capacity of water is 1 calorie · g−1 · K−1 , the
density of water is 1 g · mL−1 , and 1 calorie =
4.184 J.

010 10.0 points
The change of enthalpy symbols at the end of
the question represent the change of enthalpy
of reaction = standard enthalpy of formation.
For which reactions
I) O2 (g) + H2 (g) → H2 O2 ( )
II) C(s, diamond) + O2 (g) → CO2 (g)
III) N2 ( ) + 3 F2 (g) → 2 NF3 ( )
3
IV) C(s, graphite) + O2 (g) + H2 (g) →
2
CO2 (g) + H2 O(g)
3
V) 2 Fe(s) + O2 (g) → Fe2 O3 (s)
2
◦
would ∆Hr = ∆Hf◦ ?
1. II and IV only

1. Ccal = 47.32 calories/K; yes

2. I, II, III, IV and V

2. Ccal = 11.97 calories/K; no

3. I, III and V only

3. Ccal = −23.8 calories/K; no

4. I and II only

4. Ccal = 23.8 calories/K; no

5. I and V only

5. Ccal = 11.97 calories/K; yes

6. II, III and IV only

thomas (tt9669) – Post-lab 2 Enthalpy – lyon – (51730)
7. I, III, IV and V only
8. IV and V only
011 10.0 points
Which of the following is NOT an intensive
property of a pure substance?

3

What is ∆H for the formation of one mole
of Al2 O3 (s) from the elements?
1. +1669.8 kJ
2. −6679.2 kJ
3. −3339.6 kJ

1. specific heat

4. −1669.8 kJ

2. density

5. +3339.6 kJ

3. temperature

014
A calorimeter

10.0 points

4. heat capacity
5. color
012 10.0 points
Assume no heat energy loss to the vessel in
the following question.
3.5 g of a hydrocarbon fuel is burned in
a vessel that contains 250. grams of water
initially at 25.00 C. After the combustion,
the temperature of the water is 26.55 C. How
much heat is evolved per gram of fuel burned?

1. is only useful in measuring exothermic
reactions.
2. is equal to the molar enthalpy of reaction.
3. is a device used to measure the transfer of
heat energy.
4. is an indicator of spontaneity.
5. is a dieting aid.

1. 1263 J/g
2. 26555 J/g
3. 1764 J/g
4. 1105 J/g

015 10.0 points
When a solution of 1.691 g of silver nitrate
is mixed with an excess of sodium chloride
in a calorimeter of heat capacity 216 J/◦ C,
the temperature rises 3.03◦ C. What is the
reaction enthalpy?

5. 511 J/g

1. +65.7 kJ · mol−1

6. 143 J/g

2. −65.8 kJ · mol−1

7. 463 J/g

3. +111 kJ · mol−1

8. 73.5 J/g

4. −0.654 kJ · mol−1

013 10.0 points
Consider the reaction
2 Al2 O3 (s) → 4 Al(s) + 3 O2 (g) .
∆H = +3339.6 kJ/mol

5. +0.654 kJ · mol−1