Astudent takes a measured volume of 3.00 m hcl to prepare a 50.0 ml sample of 1.80 m hcl. what volume of 3.00 m hcl did the student use to make the sample? use mc020-1.jpg. 3.70 ml 16.7 ml 30.0 ml 83.3 ml

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