Chemistry Reference
In-Depth Information
Next, we list what we are given, identify the unknown, and write the
original formula.
Given: V
1
= 250. cm
3
; T
1
= 294 K; V
2
= 500. cm
3
Find:
T
2
V
1
T
1
V
2
T
2
Formula:
=
Note: To isolate the unknown (T
2
) we must multiply both sides by T
2
,
divide both sides by V
1
, and multiply both sides by T
1
.
Original formula
V
1
T
1
V
2
T
2
=
V
1
T
1
V
2
T
2
Multiplying both sides by T
2
, we get
T
2
×
=
× T
2
V
1
T
2
T
1
V
1
V
2
V
1
Dividing both sides by V
1
, we get
=
T
2
T
1
V
2
T
1
V
1
Multiplying both sides by T
1
, we get
T
1
×
=
V
2
T
1
V
1
Which leaves us with
T
2
=
Now, armed with this working formula, let's solve the problem.
Given: V
1
= 250. cm
3
; T
1
= 294 K; V
2
= 500. cm
3
Find:
T
2
T
2
==
(500. cm
3
)(294 K)
V
2
T
1
V
1
= 588 K
Formula:
(250. cm
3
)
Notice that you could probably have solved this problem in your head
as well, once you changed the temperature to Kelvin. Because the volume
of the gas varies directly with its Kelvin temperature, if we want to double
the volume (from 250. cm
3
to 500. cm
3
), we needed to double the tempera-
ture (from 294 K to 588 K).
Now, let's try an example where the volume is the unknown.
Example 2
A student generates a sample of hydrogen gas, which occupies 1.2 L
at 12.0
o
C. Assuming that the pressure of the gas remained constant,
what would be the volume of this gas sample at 67.0
o
C?
