# help in chemistry please!?

The element europium exists in nature as two isotopes: 151Eu has a mass of 150.9196 amu, and 153Eu has a mass of 152.9209 amu. The average atomic mass of europium is 151.96 amu. Calculate the relative percent abundance of the two europium isotopes.

Hint: what do you know about the sum of the two percent

abundances?

whats is the relative percent abundances anyway and how can we calculate it?

thanks!

Favorite Answer

But relative abundance is how often each isotype occurs, compared to each other. In thiscase there are only two so it’s just working out x the abundance out of 1 of the smaller isotope and y – the abundance of the larger one.

You have (x*150.9196)+(y*152.9209)=151.96 but y = 1-x

so (x*150.9196 +152.9209- x*152.9209 =151.96

x*-2.0013=-0.9609

x=.9609/2.0013

=0.48013

That is the smaller isotope occurs 48.014% of the time (the large occurs 51.986 of the time

That 151.96 up there just won’t show up properly

http://eppe.tripod.com/stoictry.htm