2a) Name two elements Found in waler.
b) Tap water is clean but not Pure explain what this means.
b) Name two Common water pollutante
and their effects on humans.

Hydrogen and Oxygen

Pureified water has been filtered or processed to remove impurities like chemicals and other contaminants, while tap water is not and it is composed of minerals that may not be seen in purified water.

Chemicals are the most common type of water contaminants. They affect both surface and underground water bodies. Industries and farming activities are the leading cause.

Alcohol: Probable human mrcinogen

Arsenic: Skin hyperpigmentalion: oxidative stress;

peripheral neuropathy; bladden skin,

liver, lung, and lymphatic cancer

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.