# CHEMISTRY HELP!!!

Zombie Lizzz 2009/09/24 04:57:54
I have a chemistry test tomorrow, and I don't know how to do this type of problem.

Basically, can you give me a step by step of how you did it? Please!

Isotope X-35 has an actual mass of 34.969 amu and an abundance of 75.77%. The remaining portion is made of isotope X-37 that has an actual mass of 36.966 amu.

A. Find the atomic mass for an unknown element X given the following information.

B. Identify the element on the periodic table that element X represents.

I'll love you forever, if you can teach me how!
You!

### Sort By Most Raves Least Raves Oldest Newest text size Opinions

• egglands worst! 2009/09/24 08:34:03
aight, u can do this. they practically gave u th answer...

see th amu they show? thats weight of each isotope. th abundance % tells u how much of that isotope makes up th total # of atoms of that element on average, see?

now what they want is th AVERAGE mass of BOTH of element X's isotopes, thats th atomic mass u see on th periodic table. so...

start by MULTIPLYING th amu of isotope 1 by th abundance % they gave u

34.969 (amu of an atom of isotope 1) * .7577 (abundance %) = 26.4960113

one down. now, u subtract that % (75.77) from 100 to get th remaining % number for th next isotope, so thats gonna b: 100 - 75.77 = 24.23. now do it again w/ th other isotope's amu:

36.966 (amu of isotope 2) * .2423 (abundance %) = 8.9568618

so add em up and round off, now u get 35.45. now look at ur periodic table. hmm, see chlorine?

luv u 2 snookums lol
• Zombie ... eggland... 2009/09/25 05:18:40
The funny part is that, this wasn't even on the test.

=]
• Polycra... eggland... 2009/11/07 05:58:40
Is this what they teach you in school, What r u going to do with that information. work at burger king? Pizza delivery driver, really then how long do you think it will be before you forget what you learned....half the crap they teach only applies to 1 person in each class. what a waste of money and time.
I hope you get to go to MIT and use your smarts!!!! Most kids will not have the chance
• eggland... Polycra... 2009/11/10 15:18:03
whaa? bwaha dude, i think u replies 2 th wrong thingie :P
• Polycra... eggland... 2009/11/10 20:38:56
no i didnt just goofin on ya....

wahhaaaaaahaaahaaa
• BUNNIES 2009/09/24 08:15:00
o.O

Multiply X-35's 34.969 by it's abundance of 75.77% [.7577], which would be 26.4960113.
Do the same for X-37;
Amu = 36.966

100 - 75.77 = 24.23

.36966 x 24.23 == 8.95618
35.4521913 is the Unknown element's atomic mass.. then just look on your periodic table with 35.45..ect, under the element thing.
I'm not sure if the math's right, buuut, you basically multiply each isotope's abundance by it's amu.. then add the answers together.
IF I GET THIS WRONG, DOAWNRAVE ME.(:

Btww, unknown element = Cl/Chlorine;
I think.. e.e
• Zombie ... BUNNIES 2009/09/25 05:18:53
And you are correct!

Thank you!

Living

2013/05/19 01:53:17