The evaporation rate from a spill is directly proportional to the area of the spill.

• A. False
• B. Depends on wind
• C. Depends on temperature
• D. True

Answer: (D)

Evaporation happens at the liquid’s surface, and the total amount evaporated per unit time is the rate per unit area multiplied by the exposed surface area. If you know the rate at which molecules escape per square meter (which depends on temperature, vapor pressure difference, and air movement) and you increase the surface area, you multiply that rate by the larger area. So, with wind and temperature held effectively the same, doubling the spill area doubles the evaporation rate. This is why the statement is true.

Wind and temperature do affect how fast the liquid evaporates per unit area, but they don’t destroy the proportional relationship with area; they just change the rate per unit area.