Evaporation rate factors: surface area, temperature, and air movement

Steps:

• Evaporation occurs when liquid molecules escape into the air, faster with more exposed surface, higher temperature, or drier moving air.
• Blowing air (A) removes humid air, increasing evaporation.
• Heating (B) boosts molecular energy, speeding evaporation.
• Larger beaker (D) exposes more surface area, raising evaporation rate.
• Lid (C) traps vapor, saturating air above liquid and slowing escape.

Why C is correct:

• A lid creates a closed system where water vapor accumulates, increasing partial pressure above the liquid until it equals the vapor pressure, halting net evaporation (from Raoult's law principles).

Why the others are wrong:

• A increases rate by replacing saturated air with dry air, enhancing diffusion.
• B increases rate by raising temperature, which elevates vapor pressure exponentially (Clausius-Clapeyron equation).
• D increases rate by enlarging surface area, directly proportional to evaporation.

Final answer: C