Hottest Cities in United States. Two major cities contend for the title of hottest city in the United States. The city that comes out on top depends on how you measure heat. Phoenix Arizona excels at extreme hot weather. It consistently ranks number one for the most days a year when temperatures rise above 89 Â°F or 99 Â°F. Miami challenges Phoenix for top spot on hottest year-round temperatures.
would a chemist most likely study: a leaf changing color in the fall. OR. a leaf floating on water. Follow.
Doing chemical reactions is the main focus of chemistry because that's where the action is. That's when something gets made, changed, or destroyed. So a lot of emphasis is placed on chemical reactions. Chemical reactions can be understood by these three areas of focus. A reaction is basically shuffling around the building blocks of chemistry (atoms/ions/molecules/electrons). Force & energy is what decides if the reaction occurs and how fast.