Question

Consider the following generic chemical equation:

A + B → C + D

Reactant A contains 85.1 J of chemical energy. Reactant B contains 87.9 J of chemical energy. Product C contains 38.7 J of chemical energy. If the reaction absorbs 104.3 J of chemical energy as it proceeds, how much chemical energy must product D contain? Explain your answer.

Answer 1

The law of conservation of energy states that energy is not created or destroyed during chemical reactions. The total amount of energy in the reactants, plus the energy absorbed during the reaction, must be equal to the total energy of the products.

Product D contains (85.1 J + 87.9 J + 104.3 J) – 38.7 J = 238.6 J of chemical energy.

Answer 2

Answer: 238.6 J

Step-by-step explanation:

According to the law of conservation of energy, energy can neither be created nor be destroyed. It can only be transformed from one form to another.

Endothermic reactions are those in which heat is absorbed by the system and thus the energy of products is higher than the energy of reactants.

For the given reaction:

`A+B+energy\rightarrow C+D`

Energy of A = 85.1 J

Energy of B = 87.9 J

Energy on reactant side = Energy of A + Energy of B + Energy absorbed 85.1 + 87.9 + 104.3 = 277.3 J

Energy on reactant side = Energy on product side = 277.3 J

Energy on product side = Energy of C + Energy of D

277.3 J = 38.7 J + Energy of D

Energy of D = 238.6 J

Thus chemical energy product D must contain is 238.6 J