HELP PLEASE an unknown gas has a pressure of 121.6 kPa, a volume of 31 L and a Temperature of 256K. How many moles of gas
are there?

0.031moles

Explanation:

ok so it would help if I knew the marks but 1 mole = 1000L so if the volume was 31L then if you convert you will get that answer

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol