Explain Boyle's Law and calculate the final volume of a gas given initial conditions and a final pressure. Differentiate between simple molecular and giant covalent structures.

Initial volume ($V_1$) = $400 \text{ cm}^3$  
Initial pressure ($P_1$) = $1 \text{ atm}$  
Final pressure ($P_2$) = $4 \text{ atm}$  
Final volume ($V_2$) = ?

$$
P_1V_1 = P_2V_2
$$

$$
V_2 = \frac{P_1V_1}{P_2}
$$

$$
V_2 = \frac{1 \text{ atm} \times 400 \text{ cm}^3}{4 \text{ atm}}
$$
$$
V_2 = \frac{400 \text{ atm} \cdot \text{cm}^3}{4 \text{ atm}}
$$
$$
V_2 = 100 \text{ cm}^3
$$
The volume of the gas at $4 \text{ atm}$ is $\boxed{\text{100 cm}^3}$.

b) Two properties of Covalent Compounds are:
*   They generally have **low melting and boiling points** because the intermolecular forces between molecules are weak and require little energy to overcome.
*   They are typically **poor conductors of electricity** in both solid and liquid states because they do not contain free-moving ions or delocalized electrons to carry charge.

b) Electronegativity influences bond formation by determining the **type** of bond formed between two atoms and its **polarity**:
*   If two atoms have a **small or zero difference** in electronegativity, they will share electrons relatively equally, forming a **non-polar covalent bond**.
*   If there is a **moderate difference** in electronegativity, the electrons will be shared unequally, being pulled closer to the more electronegative atom. This creates partial positive and negative charges on the atoms, resulting in a **polar covalent bond**.
*   If there is a **large difference** in electronegativity, the more electronegative atom will essentially pull the electron(s) completely away from the less electronegative atom, leading to the formation of ions and an **ionic bond**.