Question

Uranium has three common isotopes: U-238 (99.2745%), U-235 (0.7200%), U-234 (0.0055%). Calculate the average atomic mass of uranium. (Round to two decimal places)

Answer 1

Answer:

237.98

Explanation:

U-238 (99.2745%), U-235 (0.7200%), U-234 (0.0055%).

Multiply mass with percentage of abundance

238 × 99.2745 = 23627.331 %

235 × 0.72 = 169.2 %

234 × 0.0055 = 1.287 %

Add all the percentages.

23627.331 + 169.2 + 1.287 = 237978.818 %

As a whole number it is = $\frac{237978.818}{100}$

Average atomic mass of Uranium= 237.98 [rounded to 2 decimal places]