Calculating mass??

If I had 120g of 2Ca would the Mr of the 2Ca be 40 or 80?

Thanks for any help :)

Posted Sun 4th November, 2012 @ 14:19 by :) PurpleJaguar (: - Team GR

you have two Ca, so 2*Mr for Ca so 2*40 =80

The weight of Ca is irrelevant in this question.

Answered Sun 4th November, 2012 @ 14:26 by Edward Pinches

Thanks edward :)

Would you be able to answer this question for me, don't worry if you don't want to;

Calculate the maximum mass of calcium oxide that may be formed from 120g of calcium metal for the following reaction: 2Ca+O2-->2CaO

Thankyou :):)

Answered Sun 4th November, 2012 @ 14:38 by :) PurpleJaguar (: - Team GR

look at the stoichemetrics of the equation 2moles goes to 2 moles

using moles = mass/mr

n=g/mr

n=120/40 n=3moles

you know this number of moles of Ca = Ca0

rearrange n=g/mr to get g=mr*n

56*3 =168 grams

ithinks this is right

Answered Sun 4th November, 2012 @ 17:34 by Edward Pinches

YAY!

That's what i got

Thanks so much for answering this :P

Answered Mon 5th November, 2012 @ 17:24 by :) PurpleJaguar (: - Team GR