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3 years ago

Nitrogen-13 has a half-life of about 10 minutes. How much of a 320g sample of N-13 would remain after 40 minutes?

Chemistry

1 answer:

lubasha [3.4K]3 years ago

5 0

Answer:

The half-life of a radioisotope describes the amount of time it takes for said isotope to decay to one-half the original amount present in the sample.

Nitrogen-13, because it has a half-life of ten minutes, will experience two half-lives over the course of the twenty minute period. This means that 25% of the isotope will remain after this.

0.25 x 128mg = 32mg

32mg of Nitrogen-13 will remain after 20 minutes.

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. Copper(I) oxide, Cu2O, is reduced to metallic copper by heating in a stream of hydrogen gas. What mass of water is produced wh

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Answer: 0.07868 mol H₂O

Explanation:

1) Chemical equation:

Cu₂O +H₂ → 2Cu + H₂O

2) mole ratios:

1 mol Cu₂O : 1 mol H₂ : 2 mol Cu : 1 mol H₂O

3) Convert 10.00 g of Cu to grams, using the atomic mass:

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4) Use proportions

2mol Cu 0.1574 mol Cu
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That is the answer

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3 years ago

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The equilibrium constant has been estimated to be 0.12 at 25 °C. If you had originally placed 0.069 mol of cyclohexane in a 2.8

scZoUnD [109]

Answer: Concentrations of cyclohexane and methylcyclopentane at equilibrium are 0.0223 M and 0.0027 M respectively

Explanation:

Moles of cyclohexane = 0.069 mole

Volume of solution = 2.8 L

Initial concentration of cyclohexane = $\frac{moles}{Volume}=\frac{0.069}{2.8}=0.025M$

The given balanced equilibrium reaction is,

cyclohexane ⇔ methylcyclopentane

Initial conc. 0.025 M 0

At eqm. conc. (0.025-x)M (x) M

The expression for equilibrium constant for this reaction will be,

K= methylcyclopentane / cyclohexane

Now put all the given values in this expression, we get :

$0.12=\frac{(x)}{(0.025-x)}$

By solving the term 'x', we get :

x = 0.0027

Concentration of cyclohexane at equilibrium = (0.025-x ) M = (0.025-0.0027) M = 0.0223 M

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4 years ago

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The formula will be AI2O3

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Answer:

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Explanation:

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3 years ago

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