# Physics Help

A sample of ideal gas has a volume of 1.50 x 10-4 m3 at a temperature of 22°C and a pressure of 1.20 x 105Pa. If the volume of the gas remains constant, calculate the temperature (in Kelvin not °C) at which thepressure of the gas is 2.00 x 105 Pa. I dont think Im getting the right answer in the textbook the answer is = 492K Im getting 309.75 I use the formula (P1)(V1)/T1=(P2)(V2)/T2 please help me
Original post by zainshahbaz
A sample of ideal gas has a volume of 1.50 x 10-4 m3 at a temperature of 22°C and a pressure of 1.20 x 105Pa. If the volume of the gas remains constant, calculate the temperature (in Kelvin not °C) at which thepressure of the gas is 2.00 x 105 Pa. I dont think Im getting the right answer in the textbook the answer is = 492K Im getting 309.75 I use the formula (P1)(V1)/T1=(P2)(V2)/T2 please help me

ok so pV=nRT, V, n and R are all constants so :

p/T = k

hence p1/T1 = p2/T2, we want to find T2:

p2/(p1/T1) = T2 -> this is equal to (2x10^5)/(1.2x10^5/(22+273)) = 491.6666 so 492K
Original post by avery_
ok so pV=nRT, V, n and R are all constants so :

p/T = k

hence p1/T1 = p2/T2, we want to find T2:

p2/(p1/T1) = T2 -> this is equal to (2x10^5)/(1.2x10^5/(22+273)) = 491.6666 so 492K

so when I am calculating for kelvins I should add it into the formula and not at the end?
Original post by zainshahbaz
so when I am calculating for kelvins I should add it into the formula and not at the end?

yep, whenever you use the pressure/temp/volume gas equations always convert T into K first.
Original post by avery_
yep, whenever you use the pressure/temp/volume gas equations always convert T into K first.

OHHHHH thank you so much <3
Original post by zainshahbaz
OHHHHH thank you so much <3

no worries at all
Original post by avery_
no worries at all

sorry im still not getting the right answer now I got 325
Original post by zainshahbaz
sorry im still not getting the right answer now I got 325

sorry math error I accidentally put 173 instead of 273.15
Original post by zainshahbaz
sorry math error I accidentally put 173 instead of 273.15

nw haha
(Original post by zainshahbaz)so when I am calculating for kelvins I should add it into the formula and not at the end?

Original post by avery_
ok so pV=nRT, V, n and R are all constants so :

p/T = k

hence p1/T1 = p2/T2, we want to find T2:

p2/(p1/T1) = T2 -> this is equal to (2x10^5)/(1.2x10^5/(22+273)) = 491.6666 so 492K

A sample of ideal gas has a volume of 1.50 x 10-4 m3 at a temperature of 22°C and a pressure of 1.20 x 105Pa. If the volume of the gas remains constant, calculate the temperature (in Kelvin not °C) at which thepressure of the gas is 2.00 x 105 Pa.

Why 1.2x105pa is taken as 1.2x10^5pa here? Is there any conversion of metrics involved?
Original post by avery_
ok so pV=nRT, V, n and R are all constants so :

p/T = k

hence p1/T1 = p2/T2, we want to find T2:

p2/(p1/T1) = T2 -> this is equal to (2x10^5)/(1.2x10^5/(22+273)) = 491.6666 so 492K

how did u make (2x10^5) etc.. sorry im new to this topic
Original post by avery_
ok so pV=nRT, V, n and R are all constants so :

p/T = k

hence p1/T1 = p2/T2, we want to find T2:

p2/(p1/T1) = T2 -> this is equal to (2x10^5)/(1.2x10^5/(22+273)) = 491.6666 so 492K

how did u get the (2x10^5)/(1.2x10^5... sorry im confused