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tiny-mole [99]
3 years ago
15

A 50.0g g sample of 16n decays to 12.5g in 14.4 seconds. What is its half life

Chemistry
1 answer:
mixas84 [53]3 years ago
8 0
T is amount after time t 
<span>Ao is initial amount </span>
<span>t is time </span>
<span>HL is half life </span>

<span>log (At) = log [ Ao x (1/2)^(t/HL) ] </span>
<span>log (At) = log Ao + log (1/2)^(t/HL) </span>
<span>log (At) = log Ao + (t/HL) x log (1/2) </span>

<span>( log At - log Ao) / log (1/2) = t / HL </span>
<span>log (At/Ao) / log (1/2) = t / HL </span>

<span>HL = t / [( log (At / Ao)) / log (1/2) ] </span>

<span>HL = 14.4 s / [ ( log (12.5 / 50) / log (1/2) ] </span>

<span>HL = 14.4 s / 2 = 7.2 seconds </span>
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If the volume is doubled and the number of molecules is doubled, pressure is unchanged

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Can someone help.? thanks :)​
laila [671]

Answer:

  • <u>1. Equation: 2x  + 3 = 9x - 11</u>

<u></u>

  • <u>2. Each row has 2 chairs</u>

Explanation:

The variable x represents the number of chairs in each row.

<u />

<u>1. She can form 2 rows of a given length with 3 chairs left over.</u>

Thus, she has:

number of rows  number of chairs in      chairs             number of chairs

                             each row                       left over         she has

     2                        x                                    3                      2x + 3

<u>2.  She can form 9 rows of the same length if she gets 11 more chairs.</u>

That means that she is short in 11 chairs to have 9x chairs, or that she has 11 less chairs than 9x chairs. Then she has:

  • 9x - 11

<u>3. Equation:</u>

Then, number of chairs she has is 2x + 3 and, also, 9x - 11, which allows to set the equation:

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<u>4. Solve the equation:</u>

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  • 7x = 14
  • x = 2

Therefore, each row has 2 chairs, and she has 2x + 3 = 4 + 3 = 7 chairs.

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3 years ago
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