What is the total number of electron pairs shared between the carbon atom and one of the oxygen atoms in a carbon dioxide molecule?

In numbering carbon atoms in the parent chain of a hydrocarbon, why would you number from right to left, rather than left to right

Compare and contrast physical changes with chemical changes.

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.