when getting mass ratio of Zn to iodine, multiply I by 2?

Matt25 · **Joined:** Sun, 9 Oct 2005 22:53:32 UTC **Posts:** 79

when calculating the mass ratio of Zn to iodine, do you multiply Iodine's atomic mass by 2?

thelostchild · **Posted:** Tue, 25 Sep 2007 14:25:35 UTC

wouldnt it just be

(RMM of Zinc)/(RMM of Iodine)

so

65.4/126.9

= 0.516 (3sf)

Ilaggoodly · **Joined:** Thu, 15 Feb 2007 06:35:15 UTC **Posts:** 755

it is true that Iodine is diatomic... but what is it that you mean by calculating the mass ratio? usually you do that when theyre in a solution?

Matt25 · **Joined:** Sun, 9 Oct 2005 22:53:32 UTC **Posts:** 79

I did a reaction of Zn and Iodine with Zn left over.
I got the mass of iodine consumed and the mass of zinc consumed in the reaction and now I have to calculate the mass ratio of zinc to iodine in ZnI2.
My real question I guess is do i do
mass zinc/mass iodine OR mass zinc/2(mass iodine) which I guess now probably would be the first choice without multiplying by 2 because everything was taken care of as I did the experiment(it would multiply itself out in the reaction)

However, assuming I'm right above, I have another problem, far greater!
calculate the mass ratio of zinc to iodine in ZnI2 based on the chemical formula and knowledge of atomic masses.
Now this is where I'm completely halted and can't figure out wether I should be multiplying the mass of iodine by 2 or not.

If anyone one of you would be able to help me, I am forever grateful.

Ilaggoodly · **Joined:** Thu, 15 Feb 2007 06:35:15 UTC **Posts:** 755

having two molecules of iodine means having twice the mass...

Matt25 · **Joined:** Sun, 9 Oct 2005 22:53:32 UTC **Posts:** 79

so to confirm, I should not multiply mass of iodone consumed in Rxn by 2,
but should multiply the mass of iodine by 2 when calculating the mass ratio of zinc to iodine with the atomic masses from a periodic table???
THank you once again for your help and I await your response.

Ilaggoodly · **Joined:** Thu, 15 Feb 2007 06:35:15 UTC **Posts:** 755

id say so

skipjack · **Joined:** Tue, 6 Feb 2007 15:49:02 UTC **Posts:** 2594

Hmm . . . zinc and iodine . . . sounds moderately exothermic . . . how did you start the reaction, and what happened?

Matt25 · **Joined:** Sun, 9 Oct 2005 22:53:32 UTC **Posts:** 79

I started the reaction with pouring acetic acid in slowly and watched purple fumes come out and BTW, it was very hot so yes it was exothermic!

skipjack · **Joined:** Tue, 6 Feb 2007 15:49:02 UTC **Posts:** 2594

Pouring acetic acid into what?

Matt25 · **Joined:** Sun, 9 Oct 2005 22:53:32 UTC **Posts:** 79

a test tube with solid zinc and iodine in it

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when getting mass ratio of Zn to iodine, multiply I by 2?

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