<span>9370 years
First, you need to determine how many half-lives the sample has undergone. Since 67.7% has been lost, that means that 100% - 67.7% = 32.3% has been retained. So calculate the logarithm to base 2 of 0.323:
log(0.323)/log(2) = -0.490797478/0.301029996 = -1.63039393
The number -1.63039393 tells you that 1.63039393 half-lives have occurred since the mastodon died. A quick sanity check will assure you that this is true. Because after 1 half live, there would be 50% of the carbon-14 remaining. And after another half life, there would be 25% of the original carbon-14 remaining. And since 32.3% is between 25% and 50%, the value of 1.63 half lives is quite reasonable. Now just multiply the number of half lives expended by the half life of carbon-14.
1.63039393 * 5750 = 9374.765097
Rounding to 3 significant figures gives us 9370 years.</span>
Answer:
(a)
(b)
(c)
Explanation:
For a reaction involving sodium hydroxide and hydrochloric acid, the balanced equation of reaction is:
For a reaction involving sodium hydroxide and acetic acid, the balanced equation of reaction is:
For a reaction involving sodium hydroxide and phosphoric acid, the balanced equation of reaction is:
To calculate the percent
of the radioactive isotope rhenium after 3 half-lives is
(1/2)^3 = 0.125 x 100 =
12.5%
We calculate that there
is 12.5% percent activity of the radioactive isotope.
<span>Radioactive isotope
other called as radioisotope, radioactive nuclide or radionuclide, in any of
the several species of the same chemical element with different masses whose
nuclei are unstable and dissipate excess energy by spontaneously emitting
radiation in the form of gamma, alpha and beta rays. Rhenium is a chemical element
and has an atomic number of 75. Its chemical symbol is Re. It is in the
third-row transition metal in group 7 of the periodic table.</span>
Answer:
Overpopulation will strain current water resources to their limits, cause an increase in water pollution, and lead to an increase in civil and international conflicts over existing water supplies. ... Growths in regional and global population will also lead to increased cases of water pollution