A solution contains 3.75 g of a nonvolatile pure hydrocarbon in 95
g acetone. The boiling points of
pure acetone and the solutions are
55.95°C and 56.50°C, respectively.
The molal boiling-point constant of
acetone is 1.71°C kg/mol.
(i) Calculate the molarity of the
solution

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.

yes the answer is total mass in unchanged   : )