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KIM [24]
3 years ago
13

How do we know that stars explode in our galaxy?

Chemistry
1 answer:
yanalaym [24]3 years ago
5 0
We know that it is a certainty based on things such as the size, mass, brightness, etc. They can determine to within a relative level of accuracy the age. Of course they can be off by millions of years, but that’s pretty precise for a 10–20 billion year time period for the life of a star. BUT we absolutely cannot predict exactly when it will explode and we see supernovas in other galaxies, but the last one in the Milky Way that we observed was in the 1600s.
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Repeated trials and replication are the same thing. <br><br> - True<br> - False
Sauron [17]

Answer:

false

Explanation:

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3 years ago
Which of the following planets has a shorter year than Earth, as measured in Earth days? A. Uranus B. Mercury C. Saturn D. Jupit
Sergeeva-Olga [200]
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4 0
3 years ago
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What is enthalpy in chemistry pls help
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3 years ago
How many minutes will it take to plate out 2.19 g of chromium metal from a solution of Cr3+Cr3+ using a current of 55.2 amps in
Kamila [148]

Answer : The time it take to plate out will be, 3.69 minutes.

Explanation :

First we have to calculate the moles of Cr.

\text{Moles of }Cr}=\frac{\text{Mass of Cr}}{\text{Molar mass of Cr}}

Molar mass of Cr = 51.9 g/mol

\text{Moles of }Cr}=\frac{2.19g}{51.9g/mol}=0.0423mol

The cathode half-reaction is,

Cr^{3+}+3e^-\rightarrow Cr

From this we conclude that,

The number of electrons (n)  in the reaction are 3.

The quantity of charge required for the reduction of 1 mole of Cr^{3+} = 3\times F

The quantity of charge required for the reduction of 0.0423 mole of Cr^{3+} = 0.0423\times 3\times F=0.1269F=0.1269\times 96500C=12245.85C

Now we have to calculate the time taken.

We know that,

q=I\times t

t=\frac{q}{I}=\frac{12245.85C}{55.2A}=221.845s=3.69min

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4vir4ik [10]

Answer:

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Explanation:

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3 years ago
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