Question

How can I calculate the atomic mass of chlorine-35 Mass(amu) 34.969 Abundance(%) 75.78

Answer 1

you need the atomic mass of Cl-35? it's given in the question

Answer 2

isnt it 35?

Answer 3

its 34.969 amu. It seems like you're missing info though, the question doesn't seem complete.

Answer 4

im going to attach a file

Answer 5

sorry, i don't open files unless they're pdfs. It's a security thing.

Answer 6

i understand let me write the question

Answer 7

Given the information below calculate the atomic mass of chlorine.
Isotope
Chlorine-35
Mass(amu) 34.969
Abundance(%) 75.78

Answer 8

i think that they want the \(average\) atomic mass of chlorine. Do you have the mass of the other isotope(s)?

you would apply \(average=\Sigma(mass_i*Abundance_i)\)

Answer 9

yes its chlorine again
Chlorine -37
Mass (amu) 36.966
ABUNDANCE (%) 24.22

Answer 10

okay, so do you know how to apply the formula i posted? \(\Sigma\) just means sum, btw.

Answer 11

it would be 34.969*75.78

Answer 12

you need to use both of the isotopes, remember this is the average (technically the weighted average). You also have to convert the percents given, 75.78%=0.7578 (divide by 100).

Answer 13

so 34.969*.7578 and 36.966*.2422. From there am I ok with the two answers?

Answer 14

thats good. now you just need to add them up

average atomic mass = (34.969*.7578) + (36.966*.2422)

Answer 15

i get it thank you

Answer 16

cool cool, no problem.