Question

3. Describe chemical changes by giving examples of some processes and explaining them
4. Distinguish between the following giving suitable examples.
a, Natural and Human-made
b. Endothermic and Exothermic
c. Slow and Fast
d. Periodic and Non-periodic
e. Desirable and Undesirable​

Answer 1

Answer:

1 ans)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. ... An example of a chemical change is the reaction between sodium and water to produce sodium hydroxide and hydrogen.