Chemistry Help Forum dALTON LAW
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 Jul 7th 2014, 08:04 AM #1 siewlyn Junior Member   Join Date: Dec 2013 Posts: 20 dALTON LAW mixture of gases contains 16g oxygen , 14 g of nitrogen and 22g carbon dioxide. the mixture is collected above water at a temperature 25 Celsius. the total pressure is 1 atm and vapor pressure is 40 torr at 25 Celsius. what is the partial pressure of carbon dioxide? my work : mole of oxygen = 0.5 mole mole of nitrogen = 0.5 mole mole of Carbon dioxide = 0.5 mole mole fraction = number of moles CO2/ total no. of moles of gases 0.5/1.5= 0.33 total pressure is 1 atm= 760 torr water pressure is 40 torr thus, 760 torr - 40 torr = 720 torr partial pressure CO2 = total pressure * mole fraction of co2 PP co2 = 720 * 0.33= 240 TORR WHY ??? ANSWER IS 480 TORR PLEASE HELP !! THANKS YOU SO MUCH AND GOD BLESS YOU ;P
 Jul 8th 2014, 06:33 AM #2 bjhopper Senior Member   Join Date: May 2010 Posts: 491 Dalton Law Vapor pressure of water at 25 C= 23.76 mm Hg.If the total pressure is 760 mmHg then the other gasesi have partial pressure of 736.24 mm Hg.CO2 is I/3 of that or 245.4 mmHg.One mmHg =one Torr
 Jul 8th 2014, 07:25 PM #3 siewlyn Junior Member   Join Date: Dec 2013 Posts: 20 hi thanks do much !!
 Jul 8th 2014, 07:28 PM #4 siewlyn Junior Member   Join Date: Dec 2013 Posts: 20 hi i have another question... PLease help which of the following solution is the most concentrated? a. 1 M NACL b. 1 m NACL c. 55 g Of NACL mixed with 1 litre of water 1 M means 58.5g NACL in 1 L NACL right ? what's 1m means? why is the answer c but not A?

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