Question

Only 235u can be used as fuel in a nuclear reactor, so uranium for use in the nuclear industry must be enriched in this isotope. if a sample of enriched uranium has an average atomic mass of 237.482 amu, what percentage of 235u is present?

Answer 1

There are two isotopes of uranium abundant in nature

U235 and U238

As given that the sample has average molar mass of 237.482 amu

Let the amount of U235 in 100g sample = x

the amount of U238 in 100 g sample = 100-x

the average molar mass = [235(x) + 238 (100-x)] / 100

237.482 = [235(x) + 238 (100-x)] / 100

237.482 X 100 = [235(x) + 238 (100-x)]

23748.2 = 235 x + 23800 - 238x

51.8 = 3x

x = 17.27 g

So percentage of U-235 = 17.27 %