Help with my science experiment write up, please???

Question

To do with heat, expansion and gas laws.
Results were:
Pressure(Kpa) Volume(units) I/V
100 46.5 2.2
130 37 3.5
160 30 5.3
190 22.5 7.5
220 22 11.0

Help with these questions would be appreciated:
What is the relationship between the pressure and the volume of the gas when it is compressed at a constant temperature?
Would the relationship be the same if the gas had been expanded?
Is it normal for the temperature of a gas being compressedto remain constant?
Quote Boyle's law in words and state whether or not it was verified?

Any help would be good. :)

Answer 1

With increasing pressure, volume decreased and I/V increased more and more. I found a mistake in your data. At 190 Kpa and 22.5 units of volume the I/V is 8.4, not 7.5. It seems that difference of I/V is becoming larger as pressure increases, although it is inconsistent. If you looking at the differences with constantly increasing pressure: 3.5-2.2=1.3, 5.3-3.5=1.8, 8.4-5.3=3.2, 11.0-8.4=2.6. Now look at the differences of the differences:1.8-1.3=0.5, 3.2-1.8=1.4, 3.5-3.2=0.3. You see that 0.4 is approximately 0.3 but 1.4 is much different than 0.4 or 0.3. This might be due to experimental error, but it is clear that something is not right. I would have to conclude that Boyle's Law was not confirmed. By the way, what I did was to take the 1st and 2nd derivatives, which is a technique I learned in Calculus.