2.18 gg of bleach solution are treated with excess KI to generate I3- according to Equation 1 on page 161 in the lab manual. 27.08 mLmL of the standardized S2O32- solution in Part B are required to reach the endpoint of the titration. How many mmoles of S2O32- is this? (Use Equation 2.)

b. examine and describe cells

the answer is c i took the test

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