Chemical reactions either release or store energy. In endothermic reactions, energy is stored as heat, and you might notice a decrease in temperature. In exothermic reactions, heat energy is released, and temperature will increase. Chemical reactions store or release chemical energy, too. Chemical energy is stored in chemical bonds, and when bonds break, that energy is released. According to the passage, what evidence can show if a reaction is endothermic or exothermic?

a. the presence of bubbles
b. a temperature change
c. glass breaking

Agas has a volume of 0.7 l at 300 mmhg. what would be the new volume at 900 mmhg

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?

Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. an industrial chemist studying this reaction fills a 25.0l tank with 4.5 mol of sulfur dioxide gas and 4.5 mol of oxygen gas at 30.°c. he then raises the temperature, and when the mixture has come to equilibrium measures the amount of sulfur trioxide gas to be 1.4 mol. calculate the concentration equilibrium constant for the reaction of sulfur dioxide and oxygen at the final temperature of the mixture. round your answer to 2 significant digits.