Post a New Question

Science

posted by .

Natural rubidium has an average mass of 85.4678 amu and is composed of isotopes
85Rb (mass = 84.9117 amu) and 87Rb. The ratio of the isotopes 85Rb/87Rb in natural rubidium is 2.591. What is the mass of 87Rb?


Let x be the fraction of the Rb atoms that are Rb85. x/2.591 is the fraction that are Rb87

x + x/2.591 = 1
1.38595 x = 1
x = 0.7215 = fraction that is Rb85
1-x = 0.2784 = fraction that is Rb87
Avg mass = 85.4678 = (0.7215)(84.9117) + (0.2784)M87
Solve for M87

  • Science -

    M87 = 86.94 amu

  • Science -

    not a very good answer... I'm sure the person asking the question is looking for an answer that applies to every question, and not only to this one.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

More Related Questions

Post a New Question