$360 - 331/3%

Please help ✌️

The ratio pv to nrt is plotted against pressure for ch4 at 0°c and 200°c. why does the curve for 0°c drop below the horizontal line for an ideal gas whereas the curve for 200°c does not?

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

For what value of (y) is 3^3/3^y =1/9