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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: 12345676543 on June 08, 2016, 08:20:01 AM

Title: Question has little info, what now?
Post by: 12345676543 on June 08, 2016, 08:20:01 AM

A gas cylinder has a volume of 0.024m^3 and is fitted with a valve designed to release the gas if the pressure of the gas reaches 115 kPa. Calculate the pressure on the cylinder of this amount of gas at 8oC. The molar gas constant has a value of 8.31 J mol-1 K-1. At Standard Temperature and Pressure (STP) 1 mole of any gas has a volume of 0.024m^3.

How would I go about doing this? It says to calculate the pressure of "this gas" what is this gas? Is it 0.024m^3? To be able to find the pressure of 8oC I tried to find the standard temperature to go from there but which gas law is it?

Ok I've figured out the gas law but information is lacking in this for me to complete the question, what now?

Title: Re: Question has little info, what now?
Post by: mjc123 on June 08, 2016, 09:52:28 AM

I agree, there's not enough information to answer the question. All you can do is go back to your teacher and say so. (Make sure you have read the question accurately first.)

Title: Re: Question has little info, what now?
Post by: Enthalpy on June 12, 2016, 04:30:43 PM

The only possibility I see to answer would be IF the initial amount of gas is big enough to open the valve, and then the pressure is 115kPa.

Title: Re: Question has little info, what now?
Post by: AWK on June 12, 2016, 04:49:47 PM

I assume (my guess) that gas cylinder is filled at STP, then warmed. In this case pressure in cylinder without valve will be greater than 115 kPa, and with valve reach just this limit.