Answer:
C. oxygen atom
Explanation:
H2O contains two hydrogen atoms and one oxygen atom.
Answer:
key concepts and summary. When electrons move from a higher energy level to a lower one, photons are emitted, and an emission line can be seen in the spectrum. Absorption lines are seen when electrons absorb photons and move to higher energy levels
Explanation:
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Answer:
Two half lives.
Explanation:
It is known that the decay of isotopes and radioactive material obeys first order kinetics.
Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
That means for a sample 100% to decay to 50 % it will take one half-life, and to decay the remaining 50% to 25% it will take another half-life.
So, for a sample has 25% parent and 75% daughter it will have two half-lives.
Answer:
- <u><em>0.80 mol Al</em></u>
Explanation:
<u>1) Word reaction:</u>
- Aluminum + ferrous oxide → aluminum oxide + iron
This is a single replacement reaction, in which aluminum, a more acitve metal than iron, replaces the iron in the ferrous oxide to form aluminum oxide and iron.
<u>2) Skeleton chemical equation:</u>
<u>3) Balanced chemical equation:</u>
Add the coeffcients to comply with the law of conservation of mass:
<u>4) Mole ratio of Al and FeO:</u>
<u>5) Set a proportion with the unkown and solve:</u>
- x / 1.2 mol FeO = 2 mol Al / 3 mol FeO
- x = 1.2 mol FeO × 2 mol Al / 3 mol FeO =<u> </u><u>0.80 mol Al ← answer</u>
calculate the molar mass of Fe + 3(Cl)
that is your total mass
percent composition of FeCl3
mass % Fe = molar mass FE / total mass X 100 = %
mass % 3Cl = molar mass 3Cl / total mass X 100 = %
that is percent composition
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