Explain why 2.54 g of iron does not produce 2.54 g of copper in a reaction between iron and copper sulfate solution

Explanations:- The balanced equation for the reaction is:

From above reaction, there is 1:1 mol ratio between Fe and Cu. It means 1 mol of Fe will produce 1 mol of Cu.

The atomic masses of Fe and Cu are different and for this reason 2.54 g of fe does not produce 2.54 g of Cu.  

Below are the calculations that makes it more clear.

= 2.89 g Cu

So, calculations show that 2.54 g of Fe will produce 2.89 g of Cu. The difference is just because of the difference in their atomic masses.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.