[shavira]

i have purity of CaCO₃ 95%.

the reaction would be CaCO3  :rarrow:CaO + CO₂

I wanted to calculate the purity pf CaO
the method i know by using molecular weight

CaO purity = CaO/CaCO3  x 95 %
CaO = 56/100* 95% = 53.2%

Is the calculation correct?

Is that any CaCO3 purity higher than 95%?

[Borek]

You can't calculate purity of the product, not knowing how the impurity behaves during roasting. It can be left unchanged (in which case purity of the CaO will be lower than the purity of CaCO₃), it can decompose completely (in which case you will be left with 100% pure CaO).

Regardless of what the impurity is, your calculations are wrong. Purity of the CaO will be mass of CaO/mass of the sample*100%. You need to know final mass of the sample after roasting, you can calculate mass of the CaO in the sample from stoichiometry and the original sample composition.

[shavira]

in case i have 1000 gram of sample with purity of 80% CaO.
Do i can calculate purity of CaCO₃ base on purity of CaO?
or the purity just can be calculate by lab testing method?

Thank You

[Borek]

No idea what you are saying.

[shavira]

I just wanna make sure if Can I get the purity of CaO from purity of CaCO3 by calculation...
by u explanation, the purity of CaO and CaCO3 dont have any correlation by calculation.
please the explaination

[Borek]

I can only repeat what it wrote two posts earlier. Purity is

[tex]\frac {\text{mass of the substance}} {\text{mass of the sample}} 100\%[/tex]

Knowing how much CaCO₃ was present in the initial sample, and knowing the reaction equation, you can calculate how much CaO will be present in the final sample. But not knowing how the impurities behave you can't predict the final sample mass (unless you assume it doesn't decompose on roasting, which can be, but doesn't have to be, true).

[shavira]

Thank You
i understand now.