A chemistry student is given 600. mL of a clear aqueous solution at 27.° C. He is told an unknown amount of a certain compound X
is dissolved in the solution. The student allows the solution to cool to 27.° C. The solution remains clear. He then evaporates all of the water under vacuum. A precipitate remains. The student washes, dries and weighs the precipitate. It weighs 28.2 g. Using only the information from above, can you calculate the solubility of X at 21.° C?
Firstly, the molar mass of the dissolved solid is not given. This is necessary to calculate the number of moles present in solution. Secondly, solubility always has to do with temperature and the specified temperature is 27°c and not 21°c. This makes it impossible to calculate the solubility at 21°c. Further information must supplied before the solubility at 21°c can be accurately calculated.
Speed = Distance ÷ Time and since they both have different units we have to change one of them. Therefore if we change 30 minutes to half an hour we say 20km ÷ ¹/2
