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# chemistry question watch

1. Thank you got it now

Calculate the relative atomic mass of Chlorine to three significant figures given the following data.

Chlorine exists as two isotopes, 35Cl and 37Cl with relative abundance of 75% and 25%, respectively.

Can someone please explain how to get the answer.

Thank you!
2. 75/100 have mass 35 and 25/100 have mass 37

so the average is (35 x .75) + (37 x .25)
3. (Original post by EierVonSatan)
75/100 have mass 35 and 25/100 have mass 37

so the average is (35 x .75) + (37 x .25)
I don't get it can you break it down further please
4. to find the relative atomic mass of any elements you must multiply the percentage by the Ar (atomic mass). Add the answer to all elements together and divide by 100
5. This is Unit 1 Chemistry. :s
6. Multiply the 35 by its percentage, and the 37 by its percentage, and add them together. Then divide by 100 (as the percentages add up to 100).
You're basically just finding the average.
7. (Original post by The_Dark_Knight)
Calculate the relative atomic mass of Chlorine to three significant figures given the following data.

Chlorine exists as two isotopes, 35Cl and 37Cl with relative abundance of 75% and 25%, respectively.

Can someone please explain how to get the answer.

Thank you!
Chlorine exists as two isotopes

35Cl is 75% of the total Cl atoms in existence
37Cl is 25%of the total Cl atoms in existence

OK??

So to get the relative atomic mass (RAM) of Chlorine we need to bear in mind that 35Cl is 75% out of all the Cl atoms while 37Cl is only 25%. OK?

So the RAM would be 75% being 35 and 25% being 37.

So we find out what 75% of 35 (0.75*35)
and then we find out what 25% of 37 is (0.25*37)

add them up, and thats your RAM.

So you will get RAM = (35*0.75) + (37*0.25)

Any better?

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