Relative Atomic Mass of Iridium

I'm really confused on this question!

The relative atoic mass of the element iridium is 192.2. iridium occurs naturally as a mixture of iridium-191 and iridium-191. Work out the % of each isotope in naturally ocuring iridium by the following steps:
a) If the % of iridium-193 in naturally occuring iridium is x%, there must be x atoms of iridium-193 in every 100 atoms of the element. How many atoms of iridium-191 must there be in every 100 atoms of iridium?

I got 60 for that

b) What will the total relative mass of the aroms of iridium-193 in the 100 atom sample?

I don't get how you do it...

Please help :frown:

Reply 1

-Kav-

It sounds like they just want you to multiply 193 by the number of 193 atoms in the sample.

Reply 2

Jesska xD

-Kav-

It sounds like they just want you to multiply 193 by the number of 193 atoms in the sample.

So 193 x 40?

Apparentely the answer is 193... but i don't know how.

Reply 3

-Kav-

Jessikar

So 193 x 40?

Apparentely the answer is 193... but i don't know how.

Interesting. It may just be that they have some mad definition of the phrase "total relative mass" that is the same as "relative atomic mass." Either that or we're both missing something. :o:

Reply 4

Jesska xD

-Kav-

Interesting. It may just be that they have some mad definition of the phrase "total relative mass" that is the same as "relative atomic mass." Either that or we're both missing something. :o:

Apparentely the answer is 193x but the way i have worked it out, i;ve actually answered the questions a,b,c,e,f in one equation...

Reply 5

Zygroth

Jessikar

a) If the % of iridium-193 in naturally occuring iridium is x%, there must be x atoms of iridium-193 in every 100 atoms of the element. How many atoms of iridium-191 must there be in every 100 atoms of iridium?

I got 60 for that

A question wouldn't introduce x if it didn't want you to work it out or use it as part of some answer. In this case, the answer is 100-x.

b) What will the total relative mass of the aroms of iridium-193 in the 100 atom sample?

There are x atoms, and each has a relative mass of 193. The total relative mass is therefore...

Reply 6

Jesska xD

Zygroth

A question wouldn't introduce x if it didn't want you to work it out or use it as part of some answer. In this case, the answer is 100-x.

There are x atoms, and each has a relative mass of 193. The total relative mass is therefore...

Thankyou yes :smile:

The main problem i had was that i had already worked out the entire question in the first part of the answer that was meant to be 100 - x so therefore i couldn't work out what the answers for the other parts could be!