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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: medic2PA on October 06, 2010, 10:50:40 AM

Title: is this just extra info to compute RMS speed?
Post by: medic2PA on October 06, 2010, 10:50:40 AM

I'm asked to determine the RMS speed of Nitrogen at 25 deg C, but I'm also given some other information like number of grams of nitrogen and the volume of the vessel its contained in. Do I need this information? How does the number of grams of Nitrogen affect the RMS speed of nitrogen molecules, because I thought the RMS speed is just based on temp and molar mass (in this case 28g, but converted to kg = .028kg) using the equation:

sq root of 3RT/ molar mass ---------i dont see where volume or grams of nitrogren fits in. Thanks!

Title: Re: is this just extra info to compute RMS speed?
Post by: Schrödinger on October 06, 2010, 02:08:45 PM

I think there's this another formula in which you can use pressure and density to calculate RMS speed... I think it's sq root of (3P/rho)... rho=density of gas... Probably you are given mass and volume to find density and the other data to find pressure using the ideal gas equation.... Of course this is not the best way to solve this... You could directly use sq root of 3RT/M

Please correct me if I am wrong