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  • What is the rate constant of a first order reaction that is 40% complete in one hour?

    Hi,

    A first order reaction is 40% complete in one hour. What is the value of the rate constant and in how long will the reaction be 80% complete?

    I tried plotting the ln of the concentration (of the reactants) vs time (saying that at t=0 min, the concentration is 100%, and at t = 60 min, the concentration of the reactants is 60%). I don't think this is the right way to go about the question.

    I was wondering if anyone can provide some direction as to how to solve to problem? Thanks!

    (the right answer should be: k=1.42*10^-4 s^-1, and 189 min to reach 80% completion)

    1 AnswerChemistry9 years ago

  • Role of hexanes in a Diels-Alder reaction?

    Hi,

    I performed a Diels-Alder reaction between an unknown diene and maleic anhydride. The solvent was toluene. After the reaction was refluxed for 40 minutes, it was allowed to cool. Hexanes was then added dropwise to cause the product to precipitate. I was just wondering what role the hexanes plays? How does it cause the product to precipitate?

    Thanks!

    2 AnswersChemistry10 years ago

  • Why do you dissolve sample in a minimum of solvent in column chromatography?

    Hi there,

    When applying a sample to the column during chromatography, why do you dissolve it in a minimum of solvent?

    Thanks!

    1 AnswerChemistry10 years ago

  • Glitter on the dancefloor lyrics?

    Hi,

    I've been hearing this song on the radio lately and it has a line that goes "we spill glitter on the dancefloor" (or something!). Sorry that's the only part I remember... Does anyone know what song this is? Thanks!

    2 AnswersLyrics1 decade ago

  • Are -cos^(2)(1-3x) and -cos(1-3x)^2 the same thing?

    also, how would you find the derivative?

    1 AnswerMathematics1 decade ago