BCH 331 Assignment Questions and Answers

The assignment

List and explain five factors affecting entropy except
Temperature
Physical state
Number of molecules
Adhesion unto a surface and
Saturation

Five Factors Affecting Entropy (Excluding the Given Ones)

Entropy, in simple terms, is a measure of disorder or randomness in a system. Several factors can influence entropy apart from temperature, physical state, number of molecules, adhesion onto a surface, and saturation. Here are five:

1. Molecular Complexity

The more complex a molecule is, the higher its entropy. Large and branched molecules have more ways to arrange their atoms and bonds, leading to greater randomness. For example, a long-chain hydrocarbon has more entropy than a simple gas like oxygen (Oâ‚‚) because it has more possible configurations.

2. Pressure (in Gases)

When pressure increases, gas particles are forced into a smaller space, reducing their freedom of movement and decreasing entropy. On the other hand, when pressure decreases, gas molecules spread out more, increasing disorder and thus increasing entropy.

3. Mixing of Substances

When two different substances mix, entropy generally increases because the molecules of each substance spread out and intermingle. This is why solutions usually have higher entropy than their separate components. For example, when sugar dissolves in water, the sugar molecules spread out randomly, increasing disorder.

4. Phase Transitions (Other than Physical State Changes)

While the physical state itself (solid, liquid, gas) affects entropy, specific phase transitions, like crystallization or polymerization, also play a role. When a liquid forms a crystalline solid, entropy decreases because the molecules become more ordered. Similarly, when monomers link together to form a polymer, entropy decreases because the random movement of separate molecules is now restricted in a structured chain.

5. Chemical Reactions That Increase or Decrease Disorder

Some chemical reactions naturally increase entropy, while others decrease it. For example, decomposition reactions (where a compound breaks into smaller parts) tend to increase entropy because more molecules are formed, increasing randomness. On the other hand, synthesis reactions (where smaller molecules combine into a larger one) can reduce entropy by creating more ordered structures.