Chemistry Help!

Question

There are 2 main isotopes of uranium. The first has an atomic mass of 235.1 amu, and the second has an atomic mass of 238.3 amu. The abundance of the first is 1.720 % and the abundance of the second is 98.28%.

 

I did 235.1 amu x 0.1820 = 40.4372 

238.3 x 0.9828 = 234.20124 

 

40.4372 + 234.20124  = 274.6 ? the answer says it is supposed to be 238.2 amu ?? help 

Answer 1

Try (0.0172)(235.1) + (0.9829)(238.3)

Answer 2

Hi Lebron from Huntsville...hope you had a great day at school.

 

You're on the right track...however...you make two simple computing errors...which after you realize what you did will help you see that it was simple mistakes. It is always good to check your work.

 

Here is the hint to helping you...the rest you can do by yourself.

 

Hint: First you multiplied the Atomic mass of 235.1 by 0.1820...copied the numbers incorrectly.

 

Secondly...what is the decimal value of 1.720%? This is your small glitch...and when you answer that it will give you the correct answer.

 

If you need any further help...let me know...I'm on Wyzant...will be glad to assist.

Have a great evening.

Jon