A hypothetical pure element consists entirely of two isotopes. The natural percent abun- dance of theisotopewithmass 25.4 uis 82.6%. The other isotope has mass 29.5 u. Calculate the atomic weight of the naturally occurring element.
See above.
To calculate the atomic weight of the naturally occurring element, you need to consider the atomic masses and abundances of the isotopes.
Step 1: Convert the percent abundances to decimal form.
The natural percent abundance of the isotope with mass 25.4 u is 82.6%. Convert this to decimal form by dividing it by 100: 82.6% / 100 = 0.826.
Step 2: Find the atomic masses of the isotopes.
The atomic mass of the isotope with mass 25.4 u is 25.4 u, and the atomic mass of the other isotope with mass 29.5 u is 29.5 u.
Step 3: Calculate the atomic weight.
Multiply the atomic mass of each isotope by its respective abundance and then sum the results.
Atomic weight = (Atomic mass isotope 1 x Abundance isotope 1) + (Atomic mass isotope 2 x Abundance isotope 2)
Atomic weight = (25.4u x 0.826) + (29.5u x (1 - 0.826))
Atomic weight = (20.948u) + (5.000u)
Atomic weight = 25.948 u
Therefore, the atomic weight of the naturally occurring element is approximately 25.948 u.