Nitrogen is used to inflate the tire of an automobile. The volume of the tire is 0.5 m3. The pressure of the surroundings is 100 kPa. What mass, in kg, of nitrogen is required to achieve a gage pressure inside the tire of 180 kPa at 20°C?

Question

raffle_snaffle · Answer

I have an answer just want to make sure it's right.

raffle_snaffle · Answer

@zepdrix

unklerhaukus · Answer

$$pV = nRT=\frac mMRT\
m = MpV/RT$$

unklerhaukus · Answer

$$M=14.01\ \text{g/mol}\
P=80\ \text{kPa}\
V=0.5\ \text{m}^3\
T=20\ \text{°C}=\big(273.15+20\big)\text K=293.15\ \text K\
R=8.3145\ \frac{\text{m}^3\cdot\text{Pa}}{\text K\cdot\text{mol}}$$

unklerhaukus · Answer

or is $P=260\ \text{kPa}$?

unklerhaukus · Answer

*280$$P = P_\text{gague}+P_\text{ambient}=\big(180+100\big)\ \text{kPa}=280\ \text{kPa}$$

raffle_snaffle · Answer

we add P gage and P surroundings together?

raffle_snaffle · Answer

@PRAETORIAN.10

raffle_snaffle · Answer

my solution is pretty much the same except I subtracted P gage from P surroundings