If you could attach fluorescent marker tags to the enzyme that transfers the acetyl group from acetyl coa to oxaloacetate, and then detect that fluorescence with a powerful microscope, in which part of a cell would you predict to observe the fluorescence?

The fluorescence would be observed in the mitochondrial matrix.

We can arrive at this answer because:

In this case, we can state that both the fluorescence-labeled enzyme and the reaction it promotes occur in the mitochondrial matrix, being the place where we could see the fluorescence.

More information:

link

The fluorescence marker tags to the enzyme when see with a powerful microscope the fluorescence will be observed in the mitochondrial matrix of the cell.

Explanation:

The enzyme responsible for the transfer of acetyl CoA group to oxaloacetate is  ATP citrate lyase. It is produced in the matrix of the mitochondria in the cell during aerobic respiration.

The transfer of acetyl CoA group to oxaloacetate group marks start of the Kreb's cycle which also occurs in the matrix of mitochondria.

Hence the enzyme ATP citrate lyase when tagged with fluorescence will be seen in mitochondria of the cell.

and after water is usually warmed by the sun the water temperature raises and then evaporates .