Chapter 1: Chemistry is a science of change a water molecule is consisted of one oxygen(氧) atom and two hydrogen(氢) atoms A cup of water contains about 1024 water molecules Looking at he World of Aroms and Molecules 化 学Chapter 1: Chemistry is a Science of Change A water molecule is consisted of one oxygen (氧) atom and two hydrogen (氢) atoms. A cup of water contains about 1024 water molecules