1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Concentration problem

  1. Feb 11, 2009 #1
    1. The problem statement, all variables and given/known data
    Find the required mass of Al2(SO4)3.18H2O (molar mass = 666 g/mol) to prepare 50 mL of an aqueous solution, concentration = 40 mg of Al3+ per mL

    3. The attempt at a solution
    0.04 grams of Al3+/1mL = x g / 50 mL
    x = 2g

    I think this is the required mass of Al3+, now I don't know how to find how much Al2(SO4)3.18H2O do I need to get 2 g of Al3+

    The answer is 24.7g
  2. jcsd
  3. Feb 12, 2009 #2


    User Avatar

    Staff: Mentor

    How many moles of Al do you need?

    In how many moles of aluminum sulfate there will be required amount of Al?

    What will be mass of these moles?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Concentration problem Date
Mass of ammonia through nitrate concentration problem Jun 11, 2017
Easy Stoichiometry Concentration Problem Jan 5, 2016
Concentration Problem Jan 19, 2015