It is known that 40% by mass of compound XY3 is substance X. While XY3 was formed from X and Y, all 24 grams of Y substance were used, and 16 grams increased from X. What is the mass of the initial substance X in grams?
16
24
32
40
64
same question here

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.