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marissa [1.9K]
3 years ago
5

Radioactivity in our world _____.

Chemistry
1 answer:
sergij07 [2.7K]3 years ago
4 0
Radioactivity in our world <span>b. is as old as the universe.
</span><span>Radioactive atom spontaneously emits energetic particles or waves, while decays on lighter nuclei (atoms with smaller atomic mass). Radioactivity is used to calculate how old is Earth and living things, for that purpose isotope of carbon is used.</span>
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Is Coffee an Acid or a Base​
kvasek [131]
Coffee is acidic so the first one would be correct
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3 years ago
6.5 Moles of Al reacts with 7.2 Moles of H2O What is the limiting reactant and calculate the Theoretical Yield?
SVEN [57.7K]

Answer:

H₂O is the limiting reactant

Theoretical yield of 240 g Al₂O₃ and 14 g H₂

Explanation:

Find how many moles of one reactant is needed to completely react with the other.

6.5 mol Al × (3 mol H₂O / 2 mol Al) = 9.75 mol H₂O

We need 9.75 mol of H₂O to completely react with 6.5 mol of Al.  But we only have 7.2 mol of H₂O.  Therefore, H₂O is the limiting reactant.

Now find the theoretical yield:

7.2 mol H₂O × (1 mol Al₂O₃ / 3 mol H₂O) × (102 g Al₂O₃ / mol Al₂O₃) ≈ 240 g Al₂O₃

7.2 mol H₂O × (3 mol H₂ / 3 mol H₂O) × (2 g H₂ / mol H₂) ≈ 14 g H₂

Since the data was given to two significant figures, we must round our answer to two significant figures as well.

4 0
3 years ago
Select one metal which will displace Sn from a compound and form metallic tin (Sn).
zaharov [31]

Answer:

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Explanation:

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Answer:

In the 150 years since Darwin proposed the theory of evolution by natural selection, a mountain of evidence has accumulated ... How can you know what happened millions of years ago if no one was there to see it? Evidence and observation are the building blocks of all scientific inquiry; evolutionary science is no different

Explanation:

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3 years ago
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3 years ago
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