What type of reaction is Zn + CuCl2 → Cu + ZnCl2?
O
A. Decomposition
O
O
O
B. Double-replacement
c. Synthesis
D. Single-replacement

D

Explanation:

It is a single replacement reaction since Cu is singly replaced by Zn in the reaction

D,

Explanation:

The Cu in CuCl2 is replaced by Zn, so it is is a single replacement reaction.

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