Which statement best describes the difference between endothermic and exothermic reactions?

they are opposites because endothermic reactions require energy and exothermic reactions release energy.
they are opposites because endothermic reactions release energy and exothermic reactions require energy.
they the same because they are both ways of forming precipitates.
they the same because they are both ways of forming gasses.

They are opposites because endothermic reactions require energy and exothermic reactions release energy.

Explanation:

Since exothermic reactions release energy in the form of heat they are characterized by the fact that the energy levels of their reagents are higher than those of their product, which means that part of the chemical energy contained in their bonds has been released in a new way .

A chemical reaction is endothermic when it absorbs energy (heat) from the environment. In this case, heat is transferred from outside to inside the system

therefore the correct option is They are opposites because endothermic reactions require energy and exothermic reactions release energy.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west