Answer:
No One is going to answer all this because it hard to type it all in her. its easy to search it up
Explanation:
If not all of the salt has dissolved then the measurement of the concentration at the time is really inaccurate.
<h3>What is concentration?</h3>
The concentration is the amount of substance that is present in solution. We know that we can not measure the concentration unless all of the solute have been dissolved in the solution.
Thus, if not all of the salt has dissolved then the measurement of the concentration at the time is really inaccurate.
Learn more about concentration:brainly.com/question/10725862
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Answer:
a) a0 was 46.2 grams
b) It will take 259 years
c) The fossil is 1845 years old
Explanation:
<em>An unknown radioactive substance has a half-life of 3.20hours . If 46.2g of the substance is currently present, what mass A0 was present 8.00 hours ago?</em>
A = A0 * (1/2)^(t/h)
⇒ with A = the final amount = 46.2 grams
⇒ A0 = the original amount
⇒ t = time = 8 hours
⇒ h = half-life time = 3.2 hours
46.2 = Ao*(1/2)^(8/3.2)
Ao = 261.35 grams
<em>Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 34.0% of an Am-241 sample to decay?</em>
t = (ln(0.66))-0.693) * 432 = 259 years
It will take 259 years
<em>A fossil was analyzed and determined to have a carbon-14 level that is 80% that of living organisms. The half-life of C-14 is 5730 years. How old is the fossil?</em>
<em />
t = (ln(0.80))-0.693) * 5730 = 1845
The fossil is 1845 years old
Answer:
Valence electrons of selenium will be placed in s and p-orbitals.
Explanation:
Hope this helps.
