This chart shows four atoms, labeled W X Y and Z. These atoms can combine with each other to form molecules Which combination of atoms will form a molecule, bu not a compound? KDW and X K. X and Y Atom W X KDW and Z Element oxygen hydrogen carbon oxygen DIY and Z​

Explanation is in the file

cutt.ly/nz6VGda

14 days is the half-life of phosphorus-32

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