Answer:
In science, amodel is a representation of an idea, an object or even a process or a system that is used to describe and explain phenomena that cannot be experienced directly. Models are central to what scientists do, both in their research as well as when communicating their explanations.
Explanation:
Answer:
More than 40 percent measured above 5 ppb of lead, which the researchers considered an indication of a “very serious” problem.
I believe it is C; reasoning being that the hint for physical change is," the producing of a gas," chemical "that's new and diff. substance. "
Answer:
SbcI3
Explanation:
The symbol of antimony is 'Sb'.
The symbol of chlorine is 'Cl'
First write down the symbol of the first element.
Use the prefix to determine the atoms of first element. If there is no prefix on element then there is only 1 atom.
Now write down the symbol of the second element.
Use the prefix to determine the atoms of second element.
Use prefix as 'mono' for '1', 'di' for '2', 'tri' for '3' and so on.
