Question

Uranium has 3 isotopes: 234 amu at 0.0057%, 235 amu at 0.72% and 238 amu at 99.27%. calculate the massatomic.,

Answer 1

1) We need to multiply each atomic mass by its relative abundance

$U\text{ (234) = 234 u}\cdot\frac{0,0057}{100}=0,013338\text{ u}$$U\text{ (235) = 235 u}\cdot\frac{0,72}{100}=\text{ 1,692 u}$$U\text{ (238) = 238 u}\cdot\frac{99,27}{100}=\text{ 236,2626 u}$

2) Add the values above

0,0133338 u + 1,692 u + 236,2626 u = 237,9679 u