Answer to Question #338047 in General Chemistry for Carrot

Question

Direction: Solve the following problems. Attach your solutions.

1. Calculate the standard enthalpy ∆H°, for the following reaction:

2CH3OH (l) + 3O2 (g) ---> 2CO2 (g) + 2H2) (g)

Given: CH3OH (l) ∆Hf° = - 238.7 kJ

CO2 (g) ∆Hf° = - 393.5 kJ

H2O (l) ∆Hf° = - 285.8 kJ

Essay.

Water, compared to other substances, has one of the highest specific heat values. What is the advantage of this fact for the human body?

Answer 1

∆H° of reaction: 1836 kJ

Water has the highest specific heat of any common substance, 1 calorie/gm °C = 4.186 J/gm °C. This provides stability of temperature for land masses surrounded by water, provides stability for the temperature of the human body, makes it an effective cooling agent. 

The very high heat capacity makes the body a very stable environment.

For example exercise generates a lot of surplus heat since muscles have a low efficiency 18–25%. Then it takes quite some time for the body to heat up, so the body has time to take counter measures and start to sweat.

Sweat also has a high capacity to remove surplus heat from the skin. So a trained human can perform on a high level for a long time, under the right conditions outperforming most other mammals on endurance. It also allows most of the body to have a similar temperature by the blood(mostly water) circulating and spreading the heat around.

In the same way the body is quite resistant to cold. It takes quite some time to cool it down.