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How many half-lives should have elapsed if 12.5 percent of the parent isotope remains in a fossil at the time of analysis?
Wiki User
∙ 8y ago
0.5x = 0.0625
x log(0.5) = log(0.0625)
-0.30103 x = -1.20412
x = 1.20412 / 0.30103
x = 4
===========================
Check:
1/2 x 1/2 x 1/2 x 1/2 = 1/16 = 0.0625 yay!
Wiki User
∙ 14y ago
Wiki User
∙ 8y agoConvert the percent to a decimal or fraction (0.125, or 1/8), and solve the equation:(1/2)^x = 1/8 (using "^" for power)
or:
0.5^x = 0.125
In this case, you can solve the problem by inspection (just try out different powers). In more difficult cases, where the solution ISN'T an integer, you can use logarithms (basically you divide the logarithm of 0.125 by the logarithm of 0.5).
Wiki User
∙ 12y ago3.125 percent of a sample is one 32nd of a sample. In the half-life scale it is the fifth half-life. (1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, etc.)
Wiki User
∙ 10y agofour
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The time it takes for 50 percent of the nuclei in a radioactive sample to decay to its stable isotope is called?
the half-life
If the half-life of a radioactive substance is 10 hours how long will it take for 50 percent of it to decay?
The half-life of a radioactive isotope is defined as the time taken for the isotope to decay to half of its initial mass. So to decay to 50 percent of its initial mass will take one half-life of the isotope. One half-life of the isotope is 10 hours so the time taken to decay is also 10 hours.
What are the percent natural abundances of the two isotopes Ru-85 and Ru-87?
Their percent natural abundances are Ru-85 (72. 2 percent) and Ru-87 (27. 8 percent). Ru-85 and Ru-87 are the only naturally occurring isotopes of Rubidium out of its 35 known isotopes.
What is fuel enrichment - nuclear?
Natural uranium contains approx 0.7 percent U235, the rest U238. The 235 is the useful fissile isotope. Some reactors using graphite or heavy water can use natural uranium, but light water reactors need to have the U235 proportion increased to about 4 percent. this is called enrichment.
How many half-lives have elapsed when the amount of a sample's Radioactive isotopes is reduced to 3.125 percent of the original amount in the sample?
The idea is to convert the percent to a fraction (divide it by 100), and then solve the equation: (1/2)^x = (that fraction) (Note: Using "^" for "power".) In the general case, solving this equation requires logarithms. But in this specific case, you can just try out different whole numbers for "x". # 1/2 lives vs fraction 1 0.5 2 0.25 3 0.125 4 0.0625 5 0.03175 6 0.015875 The answer falls between 5 and 6 half lives, closer to 5.
Why is each isotope's mass multiplied by the isotope's percent abundance?
That is done to calculate the weighted average.
How do you calculate the atomic weight of a chemical element that has two or more isotopes?
Calculation of the atomic weight of an element having many isotopes:ia - atomic mass of the isotope a x percent concentration of the isotope in the elementib - atomic mass of the isotope b x percent concentration of the isotope in the elementic - atomic mass of the isotope c x percent concentration of the isotope in the element...........................................................................................................................iz - mass of the isotope z x percent concentration of the isotope in the elementMake the sum: I = ia + ib + ic + ..... izThe atomic weight of the element is: I/100 (the term weight is recommended by IUPAC in this case).
What is the natural percent abundance of the heavier isotope of gallium?
5%
Consider an element Z that has two naturally occurring isotopes with the following percent abundances the isotope with a mass number of 19 is 55 percent abundant the isotope with a mass number?
19.9
The 1st isotope occurs 75.47 percent of the time and has a mass of 248.7 amu the 2nd isotope occurs 24.53 percent of the time and has a mass of 249.4 amu calculate the average atomic mass?
248.90
Which uranium isotope is onley 0.7 percent of natural uranium and is the fissile part?
Uranium 235 is 0.7 percent of natural uranium and is fissile
After three half-lives what percent of the radioactive isotope is remaining?
12.5% is remaining.
What is Phenols in 5 percent percent solutions use for?
Carbohydrate analysis.
The daughter isotope is 87.5 percent if the half-life of the isotope is 150 million years how old is the sample?
a sample is brought to the laboratory and the chemist determines the percentage of the daughter isotope is 87.5%. if the half-life of the isotope is 150 million years, how old is the sample?
The percent of fixed assets to total assets is an example of?
profitability analysis
If an Isotope has a 75 year half life how long until the parent isotope has decayed to 1 percent of the initial number?
It will take between 450 and 525 years.
What is percent abundance?
Take percent abundance times atomic mass for each isotope then add all up for average atomic mass.
