the interior of the earth between a depth of 5200 kilometers and 6300 kilometers is inferred to be composed mostly of

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.

Remember that rust prevented by placing a sacrificial electrode in electrical contact with the iron. the sacrificial electrode must be composed of a metal that  oxidizes  more easily than iron (that is, it must be below iron in table 18.1).

Each calcium ion has a charge of +2, which can also be written as ca2+. if those ions move out of the neuron and no other ions are moving, the neuron would lose the positive charge associated with those ions and become more negatively charged.

The ground state electron configuration of a phosphorous atom has  three unpaired electrons. they're in the 3p sublevel. the electron configuration is: , for a total of  15 electrons.