Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Ter on December 18, 2012, 10:51:15 AM
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Hi I was wondering when to apply the molar volume for gases where you can determine the volume of a gas in a reaction given the stoichiometric coefficients of every reactant and product.
I am not sure if the following is correct, I know how I allocate A, B, C and D as the different states of matter may be wrong in terms of reaction but they are examples. Please correct me if I'm wrong.
Say
A+B->C+D
Scenario 1: I know if A, B, C, D are gases, I can use the molar volume to determine the volume of any of their gases.
Scenario 2: If A is a solid, B is a liquid and C and D are gases, if I want to find out how much A is needed to form a particular quantity of D ( maybe 3g ), then since A is not a gas, I will have to use the molar calculation method, by finding no of moles and equating then multiplying by the molar mass of A etc. I cannot use the molar volume method, simply because not all of the elements I am 'comparing' are not in gaseous state.
Scenario 3: If A is a solid, B is a gas and C is a liquid and D is a gas, if I want to find out how much B is needed to form a particular quantity of D ( maybe 3g ), then can I use the molar volume method? I'm not sure as the reaction is not all gases..
I really need to understand this.
Thank you so much!
Thanks in advance,
J
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At least all components are connected over the moles.
A + B => C + D
So you can calculate each of them. The molar Volume you can use if it is a gas. In all other cases you have to go over the molar mass.
Or what is your question?
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Thanks, sorry I wasn't clear.
I know that I can use the molar volume if it is a gas. But if let's say I want to know how much of solid A is formed from gas B, can I still use molar volume since A is not a gas?
If I want to know how much of gas A is formed from gas B and the other elements involved in the reaction are in the solid and aqueous state, can I still use molar volume since not every element in the equation is a gas?
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Yes you can use. You convert the Volume to mole and then you get the moles of your solid as well.