Ideal gas laws

[dytonn]

A rigid gas container of internal volume of 0.7m3 contains a gas at 15°C and 2.5 Bar:

State the chosen formula using the characteristic gas constant.

Transpose this making mass the subject. Find the mass, taking the characteristic gas constant of the gas as 290J/kgK

i managed to do PV/RT=m= 2.5X0.7/290X15=0.4kg

If a further 1.8 kg of gas is pumped into the container what will be the pressure when the temperature returns to 15 °C?

P=mRT/V=2.2X290X15/0.7=13.67Bar

can someone explain where I went wrong?

 

[Deleted member 4993]

A rigid gas container of internal volume of 0.7m3 contains a gas at 15°C and 2.5 Bar:

State the chosen formula using the characteristic gas constant.

Transpose this making mass the subject. Find the mass, taking the characteristic gas constant of the gas as 290J/kgK

i managed to do PV/RT=m= 2.5X0.7/290X15=0.4kg

If a further 1.8 kg of gas is pumped into the container what will be the pressure when the temperature returns to 15 °C?

P=mRT/V=2.2X290X15/0.7=13.67Bar

can someone explain where I went wrong?

How do you know you went wrong?!

Btw,

T = 273 + C

 

[dytonn]

How do you know you went wrong?!

Btw,

T = 273 + C

I got told by someone and they didnt say why.... Made me a little paranoid so thought someone else could check?

Also is that an american standardisation? Im in the UK