Using the given information, determine the cost of one no rechargeable alkaline battery ~ and compare with the cost of one rechargeable NiCad battery ~.*Assumption: The cost of the electricity to recharge the NiCad is negligible (about $0.01).NiCad batteries can be recharged (reused) 100 times. A 4 pack of AA NiCad rechargeable batteries cost $10.80.A 4 pack of AA alkaline no rechargeable batteries cost $3.69.

a:

by the combination of an unlimited number of elements

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