For each of the reactions at constant pressure, determine whether the system does work on the surroundings, the surroundings does work on the system, or essentially no work is performed.

(a) 4Fe + 3O2 --> 2Fe2O3
(b) 2H2O2 --> O2 + 2H2O

Explanation:

When work is done then there will occur change in volume. And, most change in volume occurs when there will be production of gas is taking place. We assume that no work is done when no gas is produced.

(a)   For

Here, 3 moles of gas is producing 0 moles of gas. This means that work is done on the system.

(b)  And, more is the production of a gas taking place in a reaction more will be the amount of work done by the system.

For

Here, 2 moles of a gas is producing 3 moles of a gas. Since, gas is increasing so, work will be done by the system.

2b2t

explanation:

2b2t

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.