Final answer:
Environmental hazards can be classified as physical, involving environmental factors like extreme temperatures; chemical, pertaining to harmful substances that cause toxicity; or biological, relating to disease-causing organisms. Coal burning is classified as a chemical change, and ice melting as a physical change.
Step-by-step explanation:
Classifying Environmental Hazards
To classify environmental hazards as physical, chemical, or biological, we must understand the nature of each hazard. A physical hazard involves environmental factors that can cause harm to human health without necessarily involving a substance, such as extreme temperatures or radiation. A chemical hazard refers to substances that can cause harm through chemical reactions or toxicity, like pollution or harmful household chemicals. A biological hazard includes living organisms that can cause infections or disease, such as bacteria, viruses, and other pathogens.
a. Coal burning is primarily a chemical change because it involves the chemical reaction of coal with oxygen in the air, which releases energy and various chemicals.
b. Ice melting is a physical change since the change in state from solid to liquid does not involve a chemical reaction or alter the chemical composition of the water.