Answer:
A physical change is a change that does not change the chemical properties of the substance and is purely physical.
Explanation:
The appearance of the object of chemical may change but its chemical properties are the same.
For example:
- Ice melting
- Water boiling
- Dissolving salt in water
- Cutting paper
that would be waste exchange
Answer:
False
Explanation:
According to kinetic molecular theory, all collisions are perfectly elastic and energy is conserved.
Chemical reaction is the basis of life for living organisms; no organism can remain alive without the occurrence of chemical reactions.
Chemical reactions that occur in the living organisms are called biochemical reactions, these reactions are needed for the organism to grow, develop, survive and remain alive; when the chemical reactions stop the organism die.
For instance, to remain alive one has to eat. The food eaten can not be useful to the body if the digestive enzymes do not carry out chemical reactions on it and convert it to a form that can easily enter the blood where it is needed.