Project Of Christopher Boo

Chemistry Level 2

There are two rubidium isotopes occurring in nature: $\text{Rb}^{85}$ , which has a molar mass of $84.91$ , and $\text{Rb}^{87}$ , whose molar mass is $86.92$ . The atomic mass of rubidium is $85.47$ . What is the percentage of $\text{Rb}^{87}$ out of the total existing $\text{Rb}?$