list the following substances in order of increasing molar entropy at 25'c.
H2O(l), H2O(g), H2O(s), C(s), Ar (g)
Explain your reasoning
Is it this: C(s), H2O(s), H2O(l), Ar (g), H2O(g) ?
To determine the order of increasing molar entropy at 25°C for the given substances, we need to understand the factors that affect entropy.
1. Entropy increases with an increase in the number of particles: Substances in gaseous form have more particles compared to liquid or solid forms, therefore gases generally have higher entropy than liquids or solids.
2. Entropy increases with an increase in molecular complexity: More complex molecules tend to have higher entropy compared to simpler ones.
3. Entropy increases with an increase in temperature: Higher temperatures generally lead to higher entropy due to greater molecular motion.
Now let's apply these concepts to rank the substances:
1. C(s) (Solid carbon): Solids typically have lower entropy than liquids or gases because their particles are more ordered and have less freedom of movement. Carbon is a relatively simple molecule composed of one atom, so its entropy is typically low.
2. Ar(g) (Argon gas): As a noble gas, Argon consists of individual atoms and has relatively low molecular complexity. However, being a gas, it has higher entropy compared to solids like carbon.
3. H2O(l) (Liquid water): Liquids typically have higher entropy than solids but lower entropy than gases. Since liquid water has more molecular complexity compared to Ar gas, it will generally have higher entropy.
4. H2O(s) (Ice): Ice is the solid form of water. It has a more ordered structure than the liquid phase. The molecules are closely packed and have limited freedom of movement, resulting in lower entropy compared to liquid water or water vapor.
5. H2O(g) (Water vapor): Gaseous water, also known as water vapor, has the highest entropy among the listed substances. It is a gas with higher molecular complexity compared to Ar gas, and its particles have more freedom of movement.
Therefore, the substances in increasing order of molar entropy at 25°C are:
C(s) < Ar(g) < H2O(l) < H2O(s) < H2O(g)