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Strontium consists of four isotopes with masses of 84 (abundance 0.50%), 86 (abundance of 9.9%), 87 (abundance of 7.0%), and 88 (abundance of 82.6%). What is the atomic mass of strontium?
87.71 amu (I am assuming degrees of significance here...) In order to determine the average of an element, we take the weighted average of all of the of that element....
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The atomic weight of a newly discovered element is 110.352 amu. It has two naturally occurring isotopes. One has a mass of 111.624 amu. The other has an isotopic mass of 109.75 amu. What is the percent abundance of the last isotope (109.75 amu)?
The idea here is that each isotope will contribute to the average of the element proportionally to their respective abundance. Now, the key to this problem lies in how you...
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Vanadium has two naturally occurring isotopes, 50-V with an atomic mass of 49.9472 amu and 51-V with an atomic mass of 50.9440. The atomic weight of vanadium is 50.9415. What is the percent abundance of the vanadium isotopes?
The idea with that have two naturally occurring is that the percent abundances of those two must add up to give $100%$. In calculations, it is often easier to...
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The element copper has naturally occurring isotopes with mass numbers of 63 and 65. The relative abundance and atomic masses are 69.2% for a mass of 62.93 amu and 30.8% for a mass of 64.93 amu. What is the average atomic mass of copper?
$""^63Cu$ has $69.2%$ abundance. $""^65Cu$ has $30.8%$ abundance. So, the weighted average is $62.93xx69.2%$ $+$ $64.93xx30.8%$ $=$ $63.55$ $"amu"$. If we look at , copper metal (a mixture of isotopes...
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One isotope of bromine has an atomic mass of 78.92 amu and a relative abundance of 50.69%. The other major isotope of has an atomic mass of 80.92 amu and a relative abundance of 49.31%? What is the average atomic mass of bromine?
Multiply the atomic mass of each isotope times its percent abundance in decimal form. Add them together. $"Average atomic mass of Br"$$=$$(78.92xx0.5069)+(80.92xx0.49331)="79.92 u"$
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Silver has two naturally occurring isotopes with the following isotopic masses 106.90509 and 108.9047. The average atomic mass of silver is 107.8682 amu. What is the fractional abundance of the lighter of the two isotopes?
We know that: $x_(1)106.9059 + x_(2)108.9047 = 107.8682$ $(i)$ $x_(1) + x_(2) = 1$ $(ii)$ We assume that silver has only the 2 , which for a first approximation...
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The atomic weight of a newly discovered element is 10.600 amu. It has two naturally occurring isotopes. One has a mass of 10.000 amu
and a natural abundance of 70.000%. What
is the isotopic mass of the other isotope?
So, $10.600 (mass$ $units) = 70%xx10.000 + 30%xxM_2;$ where $M_2$ is the isoptopic mass of the other isotope. So solve for $M_2$! A priori would you expect $M_2$ to...
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An element has two naturally occurring isompes widx atomic masses of 10.01 amu and 11.01 amu. The relative abundances of these elements are 19.8% and 80.2%, respectively. What is the average atomic mass of the element?
Now I hope you have been exposed to the concept of weighted average; If not here is a video Now lets get our data; Lets call our element...
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The atomic weight of Ga is 69.72 amu. There are only two naturally occurring isotopes of gallium: $"^69Ga$ with a weight of 69.0 amu, and $"^71Ga$ with a weight of 71.0 amu. What is approximate natural abundance of the $"^71Ga$ isotope?
Let the percentage of the isotope $""^71Ga$ be $=x%$ Then, The percentage of the isotope $""^69Ga$ is $=(100-x)%$ We write the mass balance equation $100*69.72=x*71+(100-x)*69$ $6972=71x+6900-69x$ $2x=6972-6900=72$ $x=36$ Therefore, The...
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The atomic mass of element A is 63.6 atomic mass units. The only naturally occurring isotopes of element A are A-63 and A-65. What is the percent abundance in a naturally occurring sample of element A closest to?
The average isotopic mass is the weighted average of the mass of the individual . Because the quoted average, $63.6$ $"amu"$, is closer to $""^63A$ than $""^65A$, the $""^63A$...
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