Dr. Smith wants to examine whether a new drug increases the maze running performance of older rats. Just like aging humans, older rats show signs of
poorer memory for new things. Dr. Smith teaches two groups of older rats to
find a piece of tasty rat chow in the maze. One group of rats is given the new
drug while they are learning the maze. The second group is not given the
drug. One week after having learned the maze he retests the rats and records
how long it takes them to find the rat chow. what is the Independent, Dependent, and Constants Variable

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