a 2L container is charged with 2atm of O2 at 298 Kelvin.
Ch4(g) + 2O2(g) --> CO2(g) + 2H20(g)
calculate the partial pressure of methane needed to react completely with the O2 in the vessel. What is the total pressure after the reaction is complete if the temperature increased to 750 Celcius?
Responses
AP chem - DrBob222, Saturday, April 11, 2009 at 11:54pm
Use PV = nRT
You know P, V, R, and T, calculate n for oxygen.
That allows you to calculate CH4 moles and from there moles CO2 and moles H2O.
Then calculate total P from new conditions for PV = nRT.
NEW:
once I have calculated the number of moles, how do i calculate the partial pressure of methane needed to completely react with O2? is that the number of moles?
I have you need .0817 moles of methane but i don't know if this is the same as partial pressure
No, moles isn't the same thing as partial pressure. I obtained an answer of 0.0818 moles CH4 needed.
Now use PV = nRT again.
You know V, R, n, and T (but T is different at the new conditions); calculate P of CH4 and that will be the partial pressure of CH4. (By the way, note the correct spelling of Celsius.)
To calculate the partial pressure of methane needed to react completely with the oxygen in the vessel, you first need to calculate the number of moles of methane required for the reaction.
From the balanced equation, you can see that 1 mole of CH4 reacts with 2 moles of O2. Since you know the number of moles of O2 in the container (which you obtained using the ideal gas law equation PV = nRT), you can calculate the number of moles of CH4 needed for complete reaction.
For example, if you calculated that there are 0.0817 moles of O2 in the container, you would need 0.0817/2 = 0.0409 moles of CH4.
To calculate the partial pressure of methane, you need to know the total pressure after the reaction is complete. Since the question mentions that the temperature increased to 750 degrees Celsius, you would need to use the new temperature to calculate the new total pressure.
Using the ideal gas law equation PV = nRT, you can rearrange the equation to solve for P:
P = (nRT) / V
Where P is the pressure, n is the number of moles, R is the ideal gas constant, T is the temperature in Kelvin, and V is the volume.
Now that you have the number of moles of CH4 (0.0409) and the new temperature in Kelvin (750 Celsius = 1023 Kelvin), you can calculate the partial pressure of methane by substituting these values into the equation above.
However, please note that this calculation only determines the partial pressure of methane after the reaction is complete. If you want to know the initial partial pressure of methane needed to react completely with the oxygen, you would need to consider the initial conditions before any reaction occurred.