how do you find pressure?

Question

a 238 ml sample of air collected at 35.O*C has a pressure of 388 torr. what will the pressure be if the volume is expanded to 444 mL at 23*C(degrees)

how do you know when you change
*c to K
or
torr to atm
etc

got any good websites?

i got 3.77 x 10^12
is that right?

Answer 1

you should probably use the equation P1V1/T1=P2V2/T2

When you use that equation, you always need to use K for temperature, but for P and V, you can use whichever units you want as long as they're the same on both sides.

so in this case,
V1 = 238
P1=388
T1 = 35+273

V2= 444
T2 = 23 + 273
P2 = x

then just solve for P2

Answer 2

You have two sets of P-V-T data, so
PV/T (one set) = PV/T second set.

You MUST change deg C to deg K whenever you do an ideal gas law calculation, since the ideal gas law is based on an absolute temperature scale.

As for using torr and atmospheres, the unit you use will determine the R constant that you choose for calculations. Remember that this constant has dimensional units of (pressure x volume) /
(deg K x number of moles)