Comments on: Chemistry Question – Mole Concepts / Qualitative Analysis

By: Wasiq

Wasiq — Mon, 11 Jan 2010 15:26:47 +0000

Hey how did you came to know that CUSO4 is the limiting reactant pls reply

By: sean

sean — Tue, 28 Oct 2008 03:21:54 +0000

% Yield = Actual Yield/Theoretical Yield x 100%

whereas

% Purity = Amt of Pure Substance/Amt of Substance used in Rxn x 100%

Hope this helps.

Cheers
Sean
Master Trainer
SimpleChemConcepts.com

By: TEC

TEC — Tue, 21 Oct 2008 06:00:39 +0000

20cm3 of a gaseous hydrocarbon was mixed with 100cm3 of oxygen and the mixture sparked so that the hydrocarbon was completely burnt. The volume of gas remaining at the end of the combustion was 70cm3. After passing over soda lime, this volume was reduced to 10cm3. All gases were measured at 25C and at the same pressure.

(a) What volume of oxygen gas remained unburnt at the end?
(b) What volume of oxygen gas was used in the combustion?
(c) What volume of carbon dioxide was produced in the combustion?
(d) Deduce the formula of hydrocarbon.

By: sean

sean — Fri, 06 Jun 2008 23:50:55 +0000

% Yield = Actual Yield/Theoretical Yield x 100%

whereas

% Purity = Amt of Pure Substance/Amt of Substance used in Rxn x 100%

Hope this helps.

Cheers
Sean
Founder & Master Trainer
SimpleChemConcepts.com

By: Helen

Helen — Wed, 28 May 2008 19:50:17 +0000

thanks alot Sean

I would to know too how to calculate percentage purity ?

The forumula for percentage yield is :

Percentage yield = achieved output/expected output * 100%

or experimental value / theoretical value * 100%