Question

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?

Direction: Solve the following problems. Attach your solutions.

1. Calculate the standard enthalpy change ΔH°, for the following reaction:

2CH3OH (l) + 3O2 (g) --> 2CO2 (g) + 2H2O (g)

Given: CH3OH (l) -------> ΔHf° = -238.7 kJ

CO2 (g) -------> ΔHf° = -393.5 kJ

H2O (l) -------> ΔHf° = -285.8 kJ

Answer 1

Specific heat is the quantity defined by the amount of heat needed to raise the temperature of 1 gram of a substance 1 degree Celsius (°C). Water has a high specific heat, meaning it takes more energy to increase the temperature of water compared to other substances. The human body contains more than 50 % of water, so it helps to control the body temperature and prevent it from overheating.

1. $2CH_3OH (l) + 3O_2 (g) = 2CO_2 (g) + 2H_2O (g)$

$\Delta H^0 = \sum \Delta H_f^0(prod) - \sum \Delta H_f^0(react)$

$\Delta H^0 = 2\Delta H_f^0(CO_2) + 2\Delta H_f^0(H_2O) -$

$- 2\Delta H_f^0(CH_3OH) +3 \Delta H_f^0(O_2)$

$\Delta H^0=2\times(-393.5) + 2 \times (-285.8) - 2\times (-238.7) +3\times 0$

$\Delta H^0=-881.2 kJ$