Identify the true statement(s) regarding the entropy of chemical substances.
a. All pure substances have a positive entropy at room temperature.
b. The dissolution of an ionic salt in water usually leads to an increase in entropy of the system (salt + water).
c. So(one mole O3(g)) > So(one mole O2(g)) at 25oC.
d. The entropy of ice at 0oC is lower than that of water at 0oC.
e. When a metallic crystal is heated, its entropy increases due to increasing atomic vibrations.
i know a, c and d are true, but im not sure about b and e
Identify the true statement(s) regarding the entropy of chemical substances.
a. Two moles of a substance at temperature T and pressure p has twice the entropy of one mole of the same substance at the same temperature and pressure.
b. Precipitation reactions are typically associated with a decrease in entropy.
c. So(one mole N2O4(g)) > So(one mole NO2(g)) at 25oC.
d. The entropy change for the reaction N2O4(g) ® 2 NO2(g) is positive.
e. Entropy increases when a 1 L cylinder of gas is opened within a 5 L evacuated cylinder.
c,d
abde
To determine whether statements b and e are true, let's analyze each statement individually and explain the reasoning behind them:
b. The dissolution of an ionic salt in water usually leads to an increase in entropy of the system (salt + water).
When an ionic salt dissolves in water, the organized, rigid crystal lattice structure of the salt breaks down, and the individual ions disperse throughout the water. This dispersal of ions increases the overall disorder or randomness of the system, leading to an increase in entropy. Therefore, statement b is true.
e. When a metallic crystal is heated, its entropy increases due to increasing atomic vibrations.
When a metallic crystal is heated, the thermal energy causes an increase in the atomic vibrations within the crystal lattice. As the atoms vibrate more vigorously, the number of microstates available to the system increases, resulting in a higher level of disorder or entropy. Therefore, statement e is also true.
In conclusion, the true statements regarding the entropy of chemical substances are: a, b, c, and d.