chemistry

I am enrolled in analytical chemistry after a 4 year break from any chemistry. I was recently given a problem set and I need some help on the following:

A 0.899g sample containing epsom salt, MgSO4 & 7 H2O, and other non-hydrated materials was dehydrated completely in a stream of hot, dry nitrogen. The resulting air stream was passed through a tube containing the desiccant magnesium perchlorate. The original weight of the desiccant tube was 61.997g and, after the determination, the tube weighed 62.318g. What is the % epsom salt in the sample.

I would appreciate any help. Thanks!

  1. 👍 0
  2. 👎 0
  3. 👁 38
asked by Kenneth
  1. The gain in weight of the perchlorate is the mass of H2O. Convert that to mols by mols = grams/molar mass H2O.
    Convert mols H2O to mols MgSO4.7H2O using the coefficient in the balanced equation below.
    MgSO4.7H2O+ heat ==> MgSO4 + 7 H2O
    mols MgSO4.7H2O = mols H2O x (1 mol MgSO4.7H2O/7H2O). (note how the units that we don't want cancel and leaves the units we want to keep.)
    Convert mols MgSO4.7H2O to grams.
    g = mols x molar mass.
    Finally,
    %MgSO4.7H2O = [mass MgSO4.7H2O/mass sample]*100 = ??
    Post your work if you get stuck.

    1. 👍 0
    2. 👎 0
    posted by DrBob222

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    How do you make a venn diagram of the 6 branches of chemistry? (Inorganic chemistry, organic chemistry, biochemistry, nuclear chemistry, physical chemistry, and analytical chemistry) like where would they go in the 3 circles

    asked by jake on August 26, 2012
  2. Choosing High School Courses

    I want to major in something English or History related, probably Secondary Education, International Studies, or Journalism. I am currently enrolled in chemistry and I am doing horribly. Would colleges rather see me take chemistry

    asked by Corinne on February 23, 2009
  3. CHEMISTRY

    how can different steps in the analytical process help in solving probs in Analytical Chemistry

    asked by Patrick on November 26, 2014
  4. just wondering...

    what is harder, chemistry or physics? because i've been struggling all year in chemistry and i'm taking physics next year... i have a solid a in alg.2 though... oh yeah, and i want to be a physical therapist. so if i'm not to good

    asked by sfdsajflkd on May 29, 2008
  5. chemistry

    Where can I find the answers to these questions in my text, "fundamentals of analytical chemistry" by skoog, west, holler and crouch. 1. Why is acetylsalicylic acid analyzed using back titration? 2. Discuss the importance of

    asked by smiley on July 14, 2007
  6. Math

    At small town high there are 100 students,each of whom takes atleast one of Biology,Chemistry,or physics.There are 50 student in Biology,60 in chemistry,and 70 in Physics.If 24 students are enrolled in exactly two of the

    asked by Luiz on May 19, 2016
  7. statistics

    At a certain college, 15% of the students receieved an A in their required math cousre, 10% receieved an A in their required chemistry course, and 5% receieved an A in both. A student is selected at random. a.) What is the

    asked by Sharon on October 4, 2009
  8. Chemistry labs in highschool

    I was curious to know whether it was standardized practice to have labs for chemistry classes in highschool. I personally have never had labs for chemistry in highschool. In my state we have the Regents. You may or may not have

    asked by ~christina~ on August 23, 2007
  9. Math

    At Small Town High there are 100 students, each of whom takes at least one of biology, chemistry, or physics. There are 50 students in biology, 60 in chemistry, and 70 in physics. If 24 students are enrolled in exactly two of

    asked by kyle on November 7, 2010
  10. chemistry

    I have a chemistry project where I need to make an object move using my knowledge of chemistry. The object os a small ball the size of a large marble. It must be moved using chemistry and NOT physics (ie slope wind etc). I am 15

    asked by Didier on April 8, 2010

More Similar Questions