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Igoryamba
2 years ago
11

Fossils provide evidence that

Chemistry
1 answer:
katrin2010 [14]2 years ago
7 0
Of these options, I'd say the third choice or "Many species of organisms that lived long ago are now extinct". I hope this helps :)
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A method used by the U.S. Environmental Protection Agency (EPA) for determining the concentration of ozone in air is to pass the
baherus [9]

Answer: 1. 9.08\times 10^{-6} moles

2. 90 mg

Explanation:

O_3(g)+2NaI(aq)+H_2O(l) \rightarrow O_2(g)+I_2(s)+2NaOH(aq)

According to stoichiometry:

1 mole of ozone is removed by 2 moles of sodium iodide.

Thus 4.54 \times 10^{-6} moles of ozone is removed by =\frac{2}{1}\times 4.54 \times 10^{-6}=9.08\times 10^{-6} moles of sodium iodide.

Thus 9.08\times 10^{-6} moles of sodium iodide are needed to remove 4.54\times 10^{-6} moles of O_3

2. \text{Number of moles of ozone}=\frac{0.01331g}{48g/mol}=0.0003moles

According to stoichiometry:

1 mole of ozone is removed by 2 moles of sodium iodide.

Thus 0.0003 moles of ozone is removed by =\frac{2}{1}\times 0.0003=0.0006 moles of sodium iodide.

Mass of sodium iodide= moles\times {\text {molar mass}}=0.0006\times 150g/mol=0.09g=90mg    (1g=1000mg)

Thus 90 mg of sodium iodide are needed to remove 13.31 mg of O_3.

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2 years ago
Radio waves are ____________ waves​
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3 years ago
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Calculate the number of molecules in 210 grams of H2O
spin [16.1K]
H2O=18.01g/mole. 210g divided by 18.01g/mole=11.653mole. 1 mole has 6.22x10^23 molecules. So there is 11.653x(6.22x10^23) molecules. Just multiply 11.653 by 6.22. Then put it as answerx10^23 molecules
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5. Base your answer to the following question on the
elixir [45]

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Explanation:

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3 years ago
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It refers to a charged particle or atom.
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<h2><u>QUE</u><u>STION</u></h2>

It refers to a charged particle or atom.

<h2><u>CHOI</u><u>CES</u></h2>

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