EVERYDAY SCIENCE

Detailed explanation-1: -In a chemical reaction, only the atoms present in the reactants can end up in the products. No new atoms are created, and no atoms are destroyed. In a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.

Detailed explanation-2: -According to the modern view of chemical reactions, bonds between atoms in the reactants must be broken, and the atoms or pieces of molecules are reassembled into products by forming new bonds. Energy is absorbed to break bonds, and energy is evolved as bonds are made.

Detailed explanation-3: -Chemical reactions involve breaking chemical bonds between reactant molecules (particles) and forming new bonds between atoms in product particles (molecules). The number of atoms before and after the chemical change is the same but the number of molecules will change.

Detailed explanation-4: -During a chemical reaction no atoms are created or destroyed. The atoms are rearranged. This results in the formation of new substances with different properties to the starting substances.

Detailed explanation-5: -Bond-breaking is an endothermic process. Energy is released when new bonds form. Bond-making is an exothermic process. Whether a reaction is endothermic or exothermic depends on the difference between the energy needed to break bonds and the energy released when new bonds form.