A chemical reaction takes place in a container
of cross-sectional area 100 cm2. As a result of
the reaction, a piston is pushed out through 19
cm against an external pressure of 630 torr.
What is the value for w for this reaction?
(Sign does matter.)
Answer in units of J
To find the value of work (w) for this reaction, we can use the formula:
w = -P * ΔV
where w represents work, P represents pressure, and ΔV represents the change in volume.
In this case, the piston is pushed out through 19 cm against an external pressure of 630 torr. However, we need to convert the pressure to the SI unit of pressure, which is Pascals (Pa).
1 torr = 1/760 atmosphere
1 atmosphere = 101325 Pa
So, we can convert 630 torr to Pascals as follows:
630 torr * (1/760) atmosphere/torr * 101325 Pa/atmosphere = 83592.1053 Pa
Now we have the pressure value (P) in Pascals.
Next, let's calculate the change in volume (ΔV). The change in volume is given by the displacement of the piston, which is 19 cm.
Converting 19 cm to meters (since SI units are used for calculations):
19 cm * (1 m / 100 cm) = 0.19 m
So, the change in volume (ΔV) is 0.19 m.
Now we can substitute the values into the formula:
w = -P * ΔV
w = -(83592.1053 Pa) * (0.19 m)
Calculating:
w = -15883.7 J
Therefore, the value of w for this reaction is -15883.7 J. The negative sign indicates that work is done on the system.