Our bodies are not very efficient. what happen to most our energy

One similarity and one difference between an element and a mixture of elements

Two solids are mixed in a flask and stirred. after a few minutes, the flask becomes cold. which of the following best describes this reaction? a. an exothermic reaction b. a combustion reaction c. an endothermic reaction d. a decomposition reaction

Avogradoa number was calculated by determining the number of atoms in?