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asambeis [7]
3 years ago
11

What is the half - life formula

Chemistry
1 answer:
VMariaS [17]3 years ago
7 0

well an example, if the half-life of a 50.0 gram sample is 3 years, then in 3 years only 25 grams would remain. During the next 3 years, 12.5 grams would remain and so on.

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Which statement about a reaction is not correct?
Vikki [24]

Answer:

D

Explanation:

A reaction that is exothermic and causes a decrease in the entropy of the system cannot be a spontaneous reaction. This is not totally true because naturally For a spontaneous process, the entropy of the universe (system plus surroundings) must increase. This is the 2nd law of thermodynamics. The system entropy can decrease as long as the entropy of the surroundings increases enough to make the sum of the system and surroundings positive.

And we know that a spontaneous reaction is a reaction that occurs in a given set of conditions without intervention. Spontaneous reactions are accompanied by an increase in overall entropy or disorder. If the Gibbs Free Energy is negative, then the reaction is spontaneous, and if it is positive, then it is nonspontaneous.

5 0
3 years ago
Calculate the energies of the n=2 and n=3 states of the hydrogen atom in Joules per<br> atom
kondor19780726 [428]

Answer:

See Explanation

Explanation:

Positional Energy for electron as function of principle energy level (n)

=> Eₙ = -A/n²; A = 2.18x10⁻¹⁸J

Positional Energy for electron in n=2 => E₂ = -2.18x10⁻¹⁸/(2)² = -5.45x10⁻¹⁹J

Positional Energy for electron in n=3 => E₃ = -2.18x10⁻¹⁸/(3)² = -2.42x10⁻¹⁹J

ΔE(n=3→2) = -5.45x10⁻¹⁹J - (-2.42x10⁻¹⁹J) =   -3.03x10⁻¹⁹J

7 0
3 years ago
What happens to the energy that is stored in cells? Check all that apply.
Delvig [45]

Answer:A, D & ECells store energy in the form ATPs.

Explanation:

5 0
3 years ago
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Please help! Due today. Look at the image:<br> Reuploaded
kirza4 [7]

Answer:

3

Explanation:

2+2=4-1=3 quick maths

8 0
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How do you think this food web would be affected if the plants were eliminated
NNADVOKAT [17]
The Answer would be C. Without plants in the ecosystem, it could not feed. Plants are mainly the only producers that feed 3rd level consumers which feed 2nd level consumers which feed 1st level consumers.
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4 years ago
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