A constant-volume gas thermometer is cal-
ibrated in dry ice (which is carbon dioxide
in the solid state and has a temperature of
−80◦C) and in boiling ethyl alcohol (78◦C).
The two pressures are 1 atm and 1.542 atm.
What value of absolute zero does the cali-
Answer in units of ◦C.
003 (part 2 of 2) 10.0 points
What is the pressure at the boiling point of
Answer in units of atm.
m = dy/dx
The Attempt at a Solution
m = (1.542-1.0)/(78-(-80)) = .0034
y-1.542 = .0034(x-78)
y-1.542 = .0034x -.2652
y = .0034x + 1.2768
if we assume temp v. pressure is linear.. and according to the text this is a good assumption
so i put the pressure equal to zero at absolute zero
0 = .0034x +1.2768
-1.2768 = .0034x
x = -1.2768/.0034 = -375.5294 C
this is wrong according to the homework program
but!... I got the second half right using that equation
boiling point of water in C is 100C so..
y=.0034(100) +1.2768 = 1.6168 atm
and this leads me to believe that my equation is correct.. what am i doing wrong?