View Full Version : Before a trip from New York to Boston, the pressure in an automobile tire is 1.8 atm
phill441
Apr 21, 2011, 09:52 PM
At 108◦C, the pressure of a sample of nitrogen is 1.44 atm. What will the pressure be at 268◦C, assuming constant volume?
Answer in units of atm.
phill441
Apr 21, 2011, 09:54 PM
Before a trip from New York to Boston, the pressure in an automobile tire is 1.8 atm at 273 K. At the end of the trip, the pressure gauge reads 1.92 atm. What is the new Cel- sius temperature of the air inside the tire? (Assume tires with constant volume.)
Answer in units of ◦C.
phill441
Apr 21, 2011, 09:56 PM
A 6.35 L sample of carbon monoxide is col- lected at 55.0◦C and 0.892 atm. What volume will the gas occupy at 1.05 atm and 59.0◦C?
Unknown008
Apr 22, 2011, 09:13 AM
QUESTION: 2
Remember the ideal gas equation.
PV = nRT
Before and after the trip, this equation will hold.
You said that the volume V is constant and it is assumed that the number of moles of the gas is constant (there was no puncture).
Then you get:
PV_k = n_k R_kT
I put a k for every constant. This means you have:
\frac{P}{T} = k
I'm calling all the constants as a single constant, k.
So at the start, you have P1 and T1 (P1 means pressure in case 1, T1 means temperature in case 1), and at the end, you have P2 and T2. Both equal to that constant k for the reasons I stated earlier.
Hence, you end up with:
\frac{P_1}{T_1} = \frac{P_2}{T_2} = k
P1 = 1.8 atm
T1 = 273 K
P2 = 1.92 atm
T2 =? K
When you get T2, just convert to degrees Celsius :)
Unknown008
Apr 22, 2011, 09:20 AM
For the other questions, can you give them a try?
Question 1, it's the same procedure, but be sure to convert the temperatures into Kelvin first.
Question 3, that's where only n and R are constants. Put a k like in my explanation above and put all the constants together to get a new equation.