Converting liquid water to solid water (ice) releases 1.44 kcal/mol energy. 1. What is the sign of AH(negative or positive) for this process? 2. Write a reaction (chemical equation) showing heat in its correct place. 3. How many kilocalories are released by freezing 32 g of water? 4. How many kilocalories are absorbed by melting 1 mol of ice?​

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