The valence electrons occur in what part of the atom?
2 answers:
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Explanation:
According to the given data, we will calculate the following.
Half life of lipase = 8 min x 60 s/min
= 480 s
Rate constant for first order reaction is as follows.
=
Initial fat concentration = 45
= 45 mmol/L
Rate of hydrolysis = 0.07 mmol/L/s
Conversion X = 0.80
Final concentration (S) =
= 45 (1 - 0.80)
= 9
or, = 9 mmol/L
It is given that = 5mmol/L
Therefore, time taken will be calculated as follows.
t =
Now, putting the given values into the above formula as follows.
t =
=
=
= 27.38 min
Therefore, we can conclude that time taken by the enzyme to hydrolyse 80% of the fat present is 27.38 min.
Answer:
- Option 4. 8.5%
Explanation:
The<em> half-life </em>time of a radiactive isotope (radioisotope) is a constant value, meaning that the amount of the radioisotope that decays will be (1/2) raised to the number of half-lives passed.
Naming A₀ the initial amount to the radioisotope, you can build this table to find the amount left.
Number of half-lives amount of radiosotope left
0 A₀
1 (1/2) × A₀
2 (1/2)×(1/2)×A₀ = (1/2)² × A₀
3 (1/2)³ ×A ₀
4 (1/2)⁴ × A₀
n (1/2)ⁿ × A₀
Now calculate the number of half-lives the strontium-90 sample has passed after 100 years:
- n = 100 years / 28.1 years ≈ 3.5587
Hence, the amount of strontium-90 is:
In percent, that is:
Rounding to two significant figures, that is 8.5%.
<u>Conclusion</u>: <em>The percent of strontium-90 left after 100 yeaers is 8.5% </em>(choice number 4).