Reactant and Product Energy Change Quick Check

In order for a reaction to occur, which action must happen?

Molecules must collide at a high enough energy to break bonds.

When sodium (Na) and chlorine (Cl) are combined, a small amount of table salt is formed and a bright yellow light and a lot of heat are given off. Does it take more energy to break the bonds of the reactants, or is more energy released when forming the bonds of the products? How do you know?

More energy is released when forming the bonds of the products because a lot of heat is given off, which indicates energy was released.

When hydrogen burns in oxygen and forms water, which bonds are broken and which bonds are formed?

Two H-H bonds are broken, one O=O bond is broken, and four H-O bonds are formed.

Molecules are not reacting using current methods. Which change can encourage a reaction?

adding heat

Which phrase best describes activation energy?

the minimum amount of energy required to break bonds and start a chemical reaction