Discussion :
A Rusting of iron nails.
1. The iron nails rust when in contact with water and air.
2. The rust is the new substance.
B Adding vinegar onto baking power
1. When vinegar is added onto baking power, bubbles of carbon dioxide are formed.
2. Carbon dioxide is the new substance.
C Burning of magnesium in air
1. When magnesium is burnt, a white powdery substance is formed.
2. The white powdery substance is the new substance.
Conclusion :
Chemical changes are the changes in a substances which produce one or more new substances that have different properties than the original substance.
Physical and chemical changes play an important role in our daily life. Some ples are listed in the table below.