CHEM 1307 Fall 2019 Midterm Exam #2
MULTIPLE CHOICE.
Select the one choice that best completes the statement or answers the question.
1)
Which gas has molecules with the slowest average molecular speed at 25°C?
A) Kr
B) CH
4
C) Ar
D) N
2
E) CO
2

2) Which of the following is a weak acid?

3)
Steam (H
2
O (g)) has a specific heat capacity of 2.01 J/g°C. Calculate
q
when 5.25 kg
of steam is cooled from 200°C to 150°C.

4) Assuming ideal behavior, what is the density of argon gas at STP?

5) Ammonia will react with fluorine to produce dinitrogen tetrafluoride and hydrogen fluoride (used
in production of aluminum, in uranium processing, and in frosting of light bulbs).
2NH
3
(
g
) + 5F
2
(
g
)
→
N
2
F
4
(
g
) + 6HF(
g
How many moles of HF
are expected if 42.2 mol of F
2
react completely with excess NH
3
?
)
A) 50.6
B) 253.
C) 42.2
D) 211.
E) 35.2

1

6)
Which represents the definition of pressure

7)
Determine the specific heat capacity of a newly developed alloy of nickel metal,
given the following calorimetry results. When a 85.66 g sample of the alloy, initially
at 90.0°C, is dropped into a coffee cup calorimeter containing 50.0 g of water at a
temperature of 10.0°C, the alloy and water reach 25.0°C at equilibrium. (Assume no
heat losses, the density of water is 1.00 g/mL and the specific heat capacity of water
is 4.18 J/g
·
°C.)