Hey guys,
I'm sure you can already sense my newbie vibes, so thanks to anyone who takes the time to give this the once over ^_^.
I was just looking for someone to check over my work and let me know if it's correct/point out the faults in my method.
"Work out the percentage abundance of the Gallium isotopes using the following information: -
Gallium: relative isotopic masses 68.95 and 70.95.
Relative atomic mass Ar = 69.72."
= r% of 68.95 plus (100% - r%) of 70.95 = 69.72
= (r ÷ 100 x 68.95) + (100 ÷ 100 x 70.95) – (r ÷ 100 x 70.95) = 69.72
= r x 0.6895 + 70.95 – r x 0.7095 = 69.72
= 0.6895r – 0.7095r + 70.95 = 69.72
= -0.02r + 70.95 = 69.72
= -0.02r = 69.72 - 70.95 = -1.23
= r = -1.23 ÷ -0.02 = 61.5
Isotopes of Gallium
Relative isotopic mass % abundance
68.95 61.5%
70.95 38.5%
Thanks so much =]