trousseli

That's great, thank you so much for your help!

First, I calculated n with the following input values: V --> Initial volume of air (0.477L=0.000477m3) P--> Initial air pressure (1 Bar=100000 Pa) T--> Initial temperature (293.15K) n=PV/RT n=(100000*0.000477)/(8.31*293.15)=0.01958 moles I used the same n value for the Air compressed pressure as the amount of substance does not change. The only variables that changed were the volume (0.000360473m3 instead of 0.000477m3 because of the oil expansion) and the temperature (358.15K instead of 293.15K). Thanks

Hi Bufrofrog, I actually did use the PV=nRT relationship and submitted above. I took into account the new volume of air decreased by the oil expansion as well as the hot temperature of 358.15K (85C). Does it seem correct to you? Thanks

Hi Studiot, Thanks for your reply. I have just made the calculation using the Boyles low and I have found a compressed air pressure of 1.32 bar (Volumeoriginal / Volumecompressed =0.477L/0.36L). However, I made an other calculation by using the PV=NRT formula (Since we talk about air, I assume using PV=NRT is allowed) and got an other result for the compressed air pressure (1.62 bar). You can see how I got this that result by looking at the file attached.

Hello, Here's my problem: I have a firm steel rectangle. dimensions : Length: 530mm Height: 610mm Width: 15mm This one is filled with oil up to 550 mm high. The rest of the volume is occupied by air. All this under normal pressure and temperature conditions. Now I put this steel rectangle on a heating device that will heat the oil up to 85C. Taking into consideration the thermal expansion of the oil, its volume will increase by 'x' m3 due to the increase in temperature (the thermal expansion of the steel will be neglected). My question is this: The new volume of oil will affect the air pressure as it will be compressed. What will be the value of this air pressure? I found the volume expansion of oil but not sure if it is correct. Could anyone enlighten me on this please? Thank you for your feedback, Friendly