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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: jjkwest1 on February 03, 2010, 08:21:06 PM

Title: colligative properties and Chemical Kinetics
Post by: jjkwest1 on February 03, 2010, 08:21:06 PM
1. The colligative effects of 1 molal sugar solution would be _________ 1 molal sodium chloride solution.
a. greater than
b. the same as
c. less than

Would it be less than since in a solution the concentration of sodium chloride would double since it splits into na+ and cl- ?

2. Ethane (C2H6) dissociates into methyl radicals by a first order reaction at elevated temperatures. If 110 mg of ethane is confined to a 500 ml reaction vessel and heated to 700 degree celsius what is the initial rate of ethane decomposition if k= 5.5 * 10^-4 s^-1 in the rate law (for the rate of dissociation of C2H6)?

What i did for this problem was that i converted .11 g of ethane into .0014 moles and then i found the molarity by .0014mol/(.5L)
which was .0028 mol/L. Then i used the 1st order rate law k[C2H6] and found that the initial rate was (5.5*10^-4)*(.0028)=
1.55*10^-6 mol/L*s. Does this approach seem correct? Thanks
Title: Re: colligative properties and Chemical Kinetics
Post by: Schrödinger on February 03, 2010, 10:33:46 PM
1. Yup
2. Yes (unless, the temperature has something to do with it :P)

Please correct me if I am wrong with the 2nd question.