Which of the following will cause an increase in the rate of evaporation of a liquid?
A. Increase in surface area
B. Increase in humidity
C. Decrease in wind speed
D. Decrease in temperature
Answer: Option A
Solution (By JKExamLibrary)
Evaporation increases with an increase in surface area, temperature, and wind speed, and decreases with an increase in humidity. A larger surface area allows more liquid molecules to be exposed to the air, enabling them to escape into the vapor phase more quickly, thus increasing the rate of evaporation.
Explanation:
Temporary hardness is due to dissolved bicarbonates of Ca and Mg. These can be removed by boiling, which precipitates carbonates. Calcium sulfate and chloride cause permanent hardness. Sodium chloride does not cause hardness. Boiling: Ca(HCO₃)₂ → CaCO₃↓ + H₂O + CO₂. Bicarbonates are formed when water containing CO₂ passes over limestone.
Explanation:
The critical temperature (Tc) is the temperature above which a gas cannot be liquefied, regardless of how much pressure is applied. Above Tc, the kinetic energy of the molecules is too high for intermolecular forces to hold them together in a liquid state, even under extreme pressure.
Explanation:
Plaster of Paris is CaSO₄·½H₂O. It is made by heating gypsum (CaSO₄·2H₂O) at 373 K. It sets with water to form gypsum again. Used for plastering fractured bones, making statues.
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