subject

Sublimation

Chemistry ⇒ States of Matter

Sublimation starts at 7 and continues till grade 12. QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Sublimation. How you perform is determined by your score and the time you take. When you play a quiz, your answers are evaluated in concept instead of actual words and definitions used.
See sample questions for grade 11
A mixture contains naphthalene and sodium chloride. Suggest a method to separate them and explain your reasoning.
A student observes that naphthalene balls in a closed container decrease in size over time. What process is responsible for this observation?
Calculate the amount of heat required to sublime 10 g of dry ice (ΔHsubl for CO2 = 571 kJ/kg).
Calculate the mass of iodine that will sublime if 11.5 kJ of heat is supplied (ΔHsubl for I2 = 62.4 kJ/mol, molar mass = 254 g/mol).
Describe a laboratory method to separate a mixture of sand and ammonium chloride using sublimation.
Describe the difference between evaporation and sublimation.
Explain why camphor disappears when left in an open dish at room temperature.
Explain why snow can disappear in cold, dry weather without melting.
Explain why sublimation is considered an endothermic process.
Name one common substance that undergoes sublimation at room temperature and pressure.
What is the reverse process of sublimation called?
A chemist wants to purify a sample of benzoic acid contaminated with a non-volatile impurity. Suggest a method based on sublimation and justify your answer.
A sample of solid carbon dioxide (dry ice) is placed in a sealed, rigid container at 25 °C. Describe and explain the changes in pressure inside the container over time, considering the process of sublimation.
Calculate the energy required to sublime 5.00 g of naphthalene (C10H8), given that its enthalpy of sublimation is 72.6 kJ/mol. (Molar mass of naphthalene = 128 g/mol)
Explain, using the concept of vapor pressure, why only certain solids undergo sublimation at atmospheric pressure while others do not.
The enthalpy of sublimation (ΔHsubl) for a substance can be expressed as the sum of its enthalpy of fusion (ΔHfus) and enthalpy of vaporization (ΔHvap). Write the mathematical relationship and explain its significance in the context of phase changes.