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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: tinkas22 on May 18, 2009, 06:14:45 PM

Title: Stiochiometry help?? Not understanding how to go from volume to mass
Post by: tinkas22 on May 18, 2009, 06:14:45 PM

Find the mass of sugar (C₆H₁₂O₆) required to produce 1.82 L of carbon dioxide gas at STP from the reaction described by the following equation:
The balanced equation is
C₆H₁₂O₆  :rarrow: 2C₂H₆O+2CO₂

I don't know how to start out the problem..  My chem teacher won't help us...

Title: Re: Stiochiometry help?? Not understanding how to go from volume to mass
Post by: ARGOS++ on May 18, 2009, 06:32:45 PM

Dear tinkas22;

Again:   - That’s a normal "Stoichiometry Problem".

Translate the Volume of CO₂ generated into moles with the help of the “Molar Volume of Gas” (MVoG) according to the table below:
      http://en.wikipedia.org/wiki/Standard_temperature_and_pressure#Molar_volume_of_a_gas

Take care for what STP should mean,  there are different meanings of it!
I would suggest for STP:  0°C and 1 atm; then the MVoG will be 22.41 L/mole.

Good Luck!
                    ARGOS⁺⁺

Title: Re: Stiochiometry help?? Not understanding how to go from volume to mass
Post by: Gerry on May 20, 2009, 11:36:57 PM

Hellow...i'm gerry from Indonesia, maybe I could help you a little to help your case. the first thing you have to do is convert volume carbon dioxide into mole unit. how? STP means the condition of this reaction is ----> 22.4 liter per mole. thus, now you'll have the mole of CO2. after that, see the completed reaction, mole ratio of glucose is a half of the carbon dioxide one. That means, now you know your glucose's mole. How weight is it? use this general equation: m = n x Mr....well then.....you'll get everything clear..  :)