Question

What is the difference between (a) a covalent bond and an ionic bond? (b) boiling point and critical point? (c) deposition and sublimation? (d) freezing point and triple point?

Short answer

(a) Compare and contrast covalent bonds and ionic bonds. Covalent bonds share electrons between two non-metal atoms, forming molecules such as water and methane, while ionic bonds involve electron transfer between a metal and a non-metal, creating charged ions held together by electrostatic forces, like in table salt (sodium chloride). (b) Explain the difference between boiling point and critical point. The boiling point is the temperature at which a substance changes from liquid to gas at atmospheric pressure, while the critical point is the temperature and pressure where liquid and gaseous phases become indistinguishable, creating a supercritical fluid. (c) Differentiate between deposition and sublimation. Deposition is the process of a substance transitioning directly from its gaseous phase to its solid phase, such as frost formation, while sublimation is the direct transition from a solid phase to a gaseous phase, like dry ice turning into carbon dioxide gas. (d) Describe the difference between the freezing point and the triple point. The freezing point is the temperature where a substance transitions from liquid to solid, while the triple point is the specific temperature and pressure where all three phases (solid, liquid, and gas) of a substance coexist in equilibrium.

Step-by-step solution

(a) Covalent Bond and Ionic Bond

Covalent bonds and ionic bonds are two types of chemical bonds found in molecules and compounds. Here are the main differences between them: Covalent bond: 1. Formed by the sharing of electrons between two atoms. 2. Occurs between non-metal atoms. 3. Results in the formation of molecules, such as water (H2O) and methane (CH4). Ionic bond: 1. Formed by the transfer of electrons from one atom to another. 2. Occurs between a metal and a non-metal atom. 3. Results in the formation of positively and negatively charged ions held together by electrostatic forces, such as table salt (sodium chloride, NaCl).

(b) Boiling Point and Critical Point

Boiling point and critical point are both related to phase transitions of a substance. Here is an explanation of their differences: Boiling point: 1. The temperature at which a substance changes from its liquid phase to its gaseous phase. 2. Requires a specific temperature at atmospheric pressure. 3. Examples: Boiling point of water is 100°C (212°F) at sea level. Critical point: 1. The temperature and pressure at which a substance's liquid and gaseous phases become indistinguishable. 2. Beyond the critical point, there is no distinction between the liquid and gaseous phases. 3. The substance is in a state called a supercritical fluid. 4. Examples: Critical point of water is 374°C (705°F) and 218 atm (22 MPa).

(c) Deposition and Sublimation

Deposition and sublimation are both phase transitions that involve a substance's solid and gaseous phases. Here is a description of their differences: Deposition: 1. The process by which a substance changes directly from its gaseous phase to its solid phase. 2. Occurs without passing through the liquid phase. 3. Examples: Frost forming on a cold surface, as water vapor in the air solidifies into ice. Sublimation: 1. The process by which a substance changes directly from its solid phase to its gaseous phase. 2. Occurs without passing through the liquid phase. 3. Examples: Dry ice sublimates at room temperature, as solid carbon dioxide turns directly into carbon dioxide gas.

(d) Freezing Point and Triple Point

Freezing point and triple point both deal with phase transitions, but they occur under different conditions. Here is an explanation of their differences: Freezing point: 1. The temperature at which a substance changes from its liquid phase to its solid phase. 2. Varies for different substances. 3. Examples: Freezing point of water is 0°C (32°F) at atmospheric pressure. Triple point: 1. The unique temperature and pressure at which all three phases (solid, liquid, and gas) of a substance coexist in equilibrium. 2. A specific point on a substance's phase diagram. 3. Examples: Water's triple point is 0.01°C (32.018°F) and 611.657 pascals (0.00604 atm).