This is not a math question, but a chemistry question, no one is answering in the chemistry section so I figured I'd ask my question here.

An element has three naturally occurring isotopes. Use the information below to calculate the weighted average atomic mass of the element, showing both the setup and the final answer for the calculation.

Question

This is not a math question, but a chemistry question, no one is answering in the chemistry section so I figured I'd ask my question here. 

An element has three naturally occurring isotopes. Use the information below to calculate the weighted average atomic mass of the element, showing both the setup and the final answer for the calculation.

anonymous · Answer

attachment

anonymous · Answer

okay, I multiplied the atomic mass by the abundance but I now the answer I got is incorrect, can someone please help explain to me how this works?

anonymous · Answer

know*

anonymous · Answer

ill do the math, give me a sec

ganeshie8 · Answer

ok hw much did u get.. . i think we need to multiply and take average

ganeshie8 · Answer

scratch that. average is not needed. just myltiplying is enough

anonymous · Answer

15.99(0.99762)+16.99)0.00038)+17.99(0.002) = 16.5697002

anonymous · Answer

thats what I got

anonymous · Answer

16.99(0.00038)*

ganeshie8 · Answer

time to burn ur calculator

anonymous · Answer

first, I converted my percentages to decimals and plugged in the numbers

ganeshie8 · Answer

wolfram says 15.99438 http://www.wolframalpha.com/input/?i=%2815.99*%2899.762%2F100%29+%2B+16.99*%28.038%2F100%29+%2B+17.99*%28.2%2F100%29+%29

anonymous · Answer

do u know what I did wrong on mine?

ganeshie8 · Answer

1 sec

anonymous · Answer

okay

anonymous · Answer

calculate it again

ganeshie8 · Answer

conversion looks okay to me, while adding something went wrong i guess

anonymous · Answer

okay, im gonna try doing it again, hold on

ganeshie8 · Answer

15.99(0.99762)+16.99(0.00038)+17.99(0.002) $\huge \ne $ 16.5697002

anonymous · Answer

okay, I got the right one, I must have made a mistake in my calculator the first time, its 15.99438 :)

ganeshie8 · Answer

awesome ! :)

anonymous · Answer

but would I write  it like that or would I have to round to get a smaller answer?

anonymous · Answer

and  I have to put a unit behind it right?

anonymous · Answer

or does it just stay like that?

anonymous · Answer

would I have to put the u behind it or something?

ganeshie8 · Answer

i  think so.. . since all masses are rounded to hundreth in the input, you may round the answer as well... an d yes unit is "u"

anonymous · Answer

okay so i could put this as 16.0 u?

ganeshie8 · Answer

u rounded too much ;)

anonymous · Answer

or too much, okay..

ganeshie8 · Answer

round it to hundreth

15.99438 ~ 15.99

anonymous · Answer

then I could do 15.99

anonymous · Answer

haha, yeah! :)

ganeshie8 · Answer

looks good :)

15.99 u

anonymous · Answer

okay thanks again so much, you have been an enormous help! :)

ganeshie8 · Answer

np :)