Register to reply 
So easy but yet I can't solve itby cpatel23
Tags: solve 
Share this thread: 
#1
Jan2714, 09:19 PM

P: 17

Hello.
I am doing a chemistry problem but it is mainly mathematics Here it is. A little info that is useful to this problem. Molar mass is always an average, given by Molar Mass = (mass of isotope1 * abundance of isotope 1) + (mass of isotope2 + abundance of isotope 2) Masses of isotopes are always constant, they do not vary from place to place. So how do I solve this? 


#2
Jan2714, 09:59 PM

Homework
Sci Advisor
HW Helper
Thanks
P: 13,052

While the molar masses do not change, the relative abundances can and do.
An element has isotopes X and Y which have molar masses m_{x} and m_{y} with percentage abundances p_{x} and p_{y} ... rearrange those variables to give an equation for the average molar mass for the element. 


#3
Jan3014, 05:11 PM

Math
Emeritus
Sci Advisor
Thanks
PF Gold
P: 39,682

If we are to assume that the two isotopes given here are the only ones we need consider, then let "x" be the relative abundance of the first (U235) and then the relative abundance of the other (U238) is 1 x.
So we must have x(235.043924)+ (1 x)(238.050784)= 238.0375. Solve that equation for x. 


Register to reply 
Related Discussions  
Trying to find an easy way to solve this  Calculus & Beyond Homework  8  
Easy problem, but no idea how to solve it?  Introductory Physics Homework  1  
I know this might be easy...but i forgot how to solve...please help ...  Calculus & Beyond Homework  7  
Easy Question Anyone Can Solve  Introductory Physics Homework  3  
Easy for you to solve, need an anwser pls  General Physics  4 