Question

Imagine a campfire on a cold day. At first, the temperature of each log is as cold as the air around it. A few hours after the fire has burned out, the temperature of the ashes will also be cold. But in between, when the fire is burning, the temperature of the logs and surrounding air is very hot. What is the source of this thermal energy? For the answer, begin by identifying the reactants and products for the overall chemical reaction of burning wood. Wood is mostly carbohydrates, the bulk of which is cellulose. Cellulose is made up of hundreds to thousands of glucose groups connectected by oxygen molecules. The chemical formula for cellulose is (C6H12O6)n, where n is the number of glucose groups. For more manageable models, carbohydrates will be modelled as glucose with a chemical formula of C6H12O6.

Answer 1

Answer:

See explanation

Explanation:

According to the first law of thermodynamics, energy can neither be created nor destroyed, but can be transformed from one form to another.

The thermal energy observed in the hot air while the fire rages is obtained from the chemical energy stored in carbohydrates(cellulose) that compose the wood material. As the wood is burnt, this chemical energy stored in chemical bonds of the wood material is converted to heat. The chemical reaction in the combustion of wood can be simply modeled as the combustion of n moles of glucose.

nC6H12O6(s) + 6nO2(g) ===> 6nCO2(g) + 6nH2O(g)

Note that n may even be thousands of glucose molecules that combine to form cellulose present in wood.