When a solution holds the maximum solute for the amount of liquid, at a given temperature, it is said to be (9) . Any time the solution has less than the maximum amount, it is said to be (10) . The amount (grams) of solute that 1 Liter of solution can hold is known as the (11) of the substance. In some cases, by (12) the solution, it is possible to increase the amount of solid solute that a solution can dissolve.

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