How are N2 , CN − , and CS alike? Mark all that are true. All three chemical species have the

a. same overall formal charge.
b. the same number of valence electrons.
c. a bond order of 3.
d. a double bond.
e. σp HOMO
f. σp* HOMO
g. πp LUMO
h. πp* LUMO

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