Chemistry
posted by Miley on .
A 3.5 liter gas sample at 20 degrees celcius and a pressure of 650 mm Hg is allowed to expand to a volume of 8570mL. The final pressure of the gas is 0.60 atm. What is the final temeperature of the gas in degrees celcius. Can anyone please show me the steps of how to do this problem! Thanks:) The answer is 230 degrees celcius!

I would use the combined gas law
P1*V1/T1 = P2*V2/T2 solve for T2. Temps are in Kelvins. 
I know that law but what are my variables to plug into there. I tried plugging them in but i didn't get the right answer. Thanks:)

You can show your work and we can find your error OR you can look to make sure the units are consistent. I suspect you have not converted 0.60 atm to mm Hg or 650 mm Hg to atm. One of them needs to be converted. In addition, one volume is given in liters and the other in mL. One of those needs to be converted. Finally, you mut use T in Kelvin. Also, note the correct spelling of Celsius.

I did all of that but i still got a different answer. Here can I'll show you all my work.
V1=3500ml T1=293K P1=650 mmHg V2=8570mL P2=45.6mmHg T2=?
Than I did 3500*650/293k=8750*45.6/X. Then I crossed multiplied and didn't get 230 degree celsius. 
pressure has to be converted to atmospheres.. 760 mm of mercury in one atmosphere
and volume has to be converted into liters.. 1000 ml in one liter
and temperature into kelvin.. 0 degrees celcius equals 273 degrees kelvin
i just worked it out and got the right answer 
THANKSSSSSSSS

Problem 1 is that 0.60 atmosphere = 0.60 x 760 mm/1 atm = 456mm and not 45.6mm.
Problem #2 is that the final T comes out in Kelvin. You must subtract 273 to get C. I plugged in all those numbers and I get 503 K which is 230 C. By the way, I notice that the original post lists 8750 mL for the final volume but you used 8570 in the calculation. I used 8570 to get the 503 K. 
I keep doing what you did to get the answer but it's not working. Can you please write out your work! Thanks:)

i try to help someone before making a post of my own.. glad i could help

(P1V1)/T1 = (P2V2)/T2
P1=650 mm
V1 = 3500 mL
T1 = 293
P2 = 456
V2 = 8570
T2 = ?
(650*3500)/293 = (8570*456)/T2
Cross multiply
650*3500*T2 = 8570*456*293
T2 = (8570*456*293)/(650*3500)
T2 = 503 K
T2 in C = 503  273 = 230 C 
A 3.67L flask is filled with carbon monoxide at 27 degrees C until the pressure is 1.27atm. Calculate the total pressure after 3.42 moles of carbon dioxide has been added to the flask. (R=0.082Latm/K mol)