A. Read the following substances commonly found in your homes, know its uses and its
composition.
1. Water (H20) is the most essential commodity for human consumption. Living things
on earth could not survive without water. (Atomic masses: H=1.019; O=16.00g from
the Periodic Table)
2. An eggshell is the hard, outer covering of an egg. It consists mostly of calcium
carbonate (CaCO3), which is a common form of calcium. (Atomic masses: Ca=40.089;
C=12.01; O=16.00g from the Periodic Table)
3. Phosphoric acid (H3PO4) is a compound used in detergents, fertilizers, toothpastes
and flavouring in carbonated beverages. (Atomic masses: H=1.01g; P= 30.979;
O=16.00g from the Periodic Table)
of each element
