A sample of oxygen, O2, occupies 32.2 mL at 30 °C and 452 torr. What volume will it occupy at -70 °C and the same pressure? O 22.2 mL
O 21.6 mL
O 23.9 mL

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

the answers are

c and c