Naturally occuring boron is 80.20% boron-11 and 19.80% of some other isotopic form of boron. What must be the atomic mass of this second isotope be in order to account for the 10.81 amu average atomic mass for boron?

Do you have the mass of B-11?

Let X = mass B-X , then,

0.8020(mass B-11) + 0.1980(X) = 10.81
Substitute mass B-11 and solve for X

10.0amu

b is for b and d is for ak

To determine the atomic mass of the second isotope, we need to use the given information:

1. The natural abundance of boron-11 is 80.20%. This means that 80.20% of all boron atoms in nature are boron-11.

2. The natural abundance of the second isotope is 19.80%. This is the percentage of boron atoms that are the second isotope.

3. The average atomic mass of boron is 10.81 amu.

Based on this information, we can set up an equation to solve for the atomic mass of the second isotope:

(Atomic mass of boron-11) x (Fractional abundance of boron-11) + (Atomic mass of the second isotope) x (Fractional abundance of the second isotope) = Average atomic mass of boron

Let's plug in the values we have:

(11 amu) x (0.8020) + (Atomic mass of the second isotope) x (0.1980) = 10.81 amu

Now we can solve for the atomic mass of the second isotope:

(11 amu x 0.8020) + (Atomic mass of the second isotope x 0.1980) = 10.81 amu
8.822 amu + (Atomic mass of the second isotope x 0.1980) = 10.81 amu
(Atomic mass of the second isotope x 0.1980) = 10.81 amu - 8.822 amu
(Atomic mass of the second isotope x 0.1980) = 1.988 amu

Now we can solve for the atomic mass of the second isotope by dividing both sides of the equation by 0.1980:

Atomic mass of the second isotope = 1.988 amu / 0.1980
Atomic mass of the second isotope ≈ 10.03 amu

Therefore, the atomic mass of the second isotope must be approximately 10.03 amu in order to account for the average atomic mass of boron.