13) Lithium and nitrogen react to produce lithium nitride: 6Li (s) + N2 (g)  2Li3N (s)
How many moles of N2 are needed to react with 0.500 mol of lithium?
A) 3.00
B) 0.500
C) 0.167
D) 1.50
E) 0.0833

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personal, she chose to do it.

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