CHEM 234 Assignment 1.docx-CHEM 234 - Fa...
CHEM_234_Assignment_1.docx-CHEM 234 - Fall 2014 Assignment
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CHEM 234 Assignment 1.docx-CHEM 234...
CHEM_234_Assignment_1.docx-CHEM 234 - Fall 2014 Assignment
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CHEM 234
- Fall 2014
Assignment #1 (5 points)
Due date: September 18th, 2014
Question 1: (1 point)
The mass of air in our classroom was evaluated to be around
450 kg, when estimating
that air is composed of 79% nitrogen (N
2
) and 21% oxygen (O
2
). What difference in mass
could you calculate, if any, if air had been estimated to be composed of 100% nitrogen,
2
and 21% O
2
?
Question 2: (1 point)
In an industrial process, nitrogen has to be heated to 500 K at a constant volume of
1.000m
3
. The gas enters the container at 300 K and 100 atm. The mass of the gas is 92.4
kg. Use the van der Waals equation to determine the approximate pressure of the gas at
its working temperature of
500 K. For nitrogen, a = 1.352 dm
6
atm mol
-2
, and b= 0.0387
dm
3
mol
-1
.
Question 3 :
(1 point)
Calculate the work needed for a bird of mass 135 g to fly to a height of 60 m from the
surface of the Earth.
Question 4: (2 points)
A sample consisting of 1.0 mol of solid calcium carbonate (CaCO
3
) was heated to 800°C,
when it decomposed. The heating was carried out in a container fitted with a piston that
was initially resting on the solid. Calculate the work done during the complete
decomposition of the sample at 1.0 atm. What work would be done if instead of having a
piston, the container was open to the atmosphere?