7. A pupil was asked to investigate three metal oxides XO, Y20 and ZO. On heating strongly, XO broke down into a metal X and oxygen. The other two oxides did not break down.
a) From this evidence what can be deduced about the reactivity of metal X?

b) How could you test Y20 and ZO in order to find out which was the more reactive of the metals Y and Z?

more infor would

a lot

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