Answer:
Chemical reaction, compound, molecule, covalent bonds, ionic bonds, ions. (first page)
Oxygen and hydrogen, 1 hydrogen 2 oxygen, H2O, a covalent bond, then mark off is always a liquid. (Second page)
Explanation:
What are you making a hypothesis for
Explanation:
A physical change is change that alters the physical properties of matter especially its form and state.
In many cases, the change is easily reversible.
Examples are change of state such as boiling, melting, freezing, condensation, sublimation e.t.c
A chemical change is one in which a new kind of matter is formed. It is always accompanied by energy changes.
Examples are combustion, rusting , precipitation, milk souring.
- Chemical changes are irreversible
- Physical changes do not lead to the formation of new kinds of matter.
- Most physical changes requires little energy.
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Answer:
Extinction
Explanation:
When a species becomes extinct, every last specimen has died out
Environmental Hazards are usually any chemicals that donot naturally occur to exist anywhere and are usually made in the fields of industry or experimental sciences
So if you happen for example to throw a bit of mercury in some river while being in a school trip then this is an environmental hazard created by humans
