Answer:
19
Explanation:
The mass of an atom is found in the nucleus: number of protons + number of neutrons; 9 + 10 = 19
The mass number of fluorine is 19
Answer:
1. A substance that can be separated into two or more substances only by a chemical change is a(n) _____.
solution
element
mixture
compound
2.
Which of the following materials is a substance?
air
gasoline
stainless steel
silver
3.
The first figure in a properly written chemical symbol always is _____.
boldfaced
capitalized
italicized
underlined
4.
Which of the following represents a compound?
H
H-3
H2O
O-16
5. What do chemical symbols and formulas represent, respectively?
elements and compounds
atoms and mixtures
compounds and mixtures
elements and ions
Explanation:
Answer:
force is a derived quantity
work is a fundamental quantity
2.Force is measured in Newton why work is measured in Newton per seconds (N/s)
Explanation:
no
(1) Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect. (2) A greenhouse stays warm because sunlight and heat coming through the glass roof are mostly trapped. (3) The heat doesn't radiate back into the atmosphere because it's held in by the glass. (4) Something like that happens on Earth. (5) The atmosphere acts like a blanket that keeps the Sun's heat from leaking away into space.
What is the main conclusion you are to draw from this paragraph?
A. The atmosphere is what keeps the planet warm.
B. The greenhouse effect is changing Earth's atmosphere.
C. The sun's heat can easily leak away out into space.
D. Greenhouses help most plants to grow more quickly.
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