The way it says to do it in the book (multiply mass of each isotope by it's natural abundance, expressed as a decimal and then add the products) confuses me a lot. Can someone dumb it down for me and give an example. I have a chemistry exam tomorrow and I need to know this. Thanks
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AMU is average (rounded) atomic number (number of protons) plus number of neutrons in nature, or the number underneath the element name, for example, cl (chlorine) has an AMU of 35.5.
another way to do it is this.. ill write out a problem, calculate the average atomic mass of iridium using the following data for two iridium isotopes.
isotope- ir-191 and ir-193 (the AMU of each is 191.0 and 193.0, the relative abundance is 0.3758 and 0.6242)
next you'd just multiply each AMU (191.0 and 193.0) by their relative abundance (0.3758 and 0.6242)
you should get 71.778 and 120.47
add them to get 192.2 AMU
does this help?
by the way my shift key is broken that's why the c in cl is not capitalised sorry about that. it should be though.
another way to do it is this.. ill write out a problem, calculate the average atomic mass of iridium using the following data for two iridium isotopes.
isotope- ir-191 and ir-193 (the AMU of each is 191.0 and 193.0, the relative abundance is 0.3758 and 0.6242)
next you'd just multiply each AMU (191.0 and 193.0) by their relative abundance (0.3758 and 0.6242)
you should get 71.778 and 120.47
add them to get 192.2 AMU
does this help?
by the way my shift key is broken that's why the c in cl is not capitalised sorry about that. it should be though.