When an athlete gets hurt they apply sometimes an instant cold pack to the injury. the instant cold pack works by mixing two chemicals that create a chemical reaction. what evidence is there that a chemical reaction is taking place in the cold pack?
a. change in odor
b. change in color
c. formation of gas
d. temperature change

16. why must the number of electrons lost equal the number of electrons gained in every redox reaction? use 3 – 4 sentences in your own words to address this question. 18. what type of radiation is emitted when chromium-51 decays into manganese-51? show the nuclear equation that leads you to this answer. 19. a radioactive nucleus alpha decays to yield a sodium-24 nucleus in 14.8 hours. what was the identity of the original nucleus? show the nuclear equation that leads you to this answer.

Which of the following units is not an official si unit

•hydration •dissociation •dissolving which one goes to which