[notepad]

Let's say I have a reaction of of all gases with the form 2A -> 4B + C. If I start with 100 Torr of A, and the reaction goes to completion what is the total pressure of the system? Is it 250 Torr (200 from B, and 50 from C)? If this is correct, why can I treat pressure like moles?

[rabolisk]

Well, let me ask you. If pressure can be treated like moles, that means that when a reaction results in double the amount of gas, the pressure also doubles. Using the ideal gas law, PV=nRT, convince yourself that this is only true under specific circumstances... Then derive what these specific circumstances are.

[dzoys]

Let's say I have a reaction of of all gases with the form 2A -> 4B + C. If I start with 100 Torr of A, and the reaction goes to completion what is the total pressure of the system? Is it 250 Torr (200 from B, and 50 from C)? If this is correct, why can I treat pressure like moles?

you are given the torr per A,B,C for ONE MOLE...

in the given equation you have MORE THAN ONE mole in the coefficients.

apply algebra...

 you are given 100 torr as the measured standard for 1 moles of A.... but you have 2 moles of A in the equation... you plug it in to match your equation.