Which of the following is NOT a sign of a chemical change? Mixing two white powders in water and the resulting mixture turns red in color.
Steam collecting on the lid of a pot of boiling water.
Cracking a light stick which starts to glow.
a
Putting drops of water on calcium carbonate and watching bubbles appear.

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a

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.

here are some of the ways in which chemical and nuclear reactions differ.

explanation: