chemistry

posted by .

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!

  • chemistry -

    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.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry

    A hydrated MgSO4 salt, weighing 3.211g, is heated in a crucible until reaching a constant weight. The weight of the anhydrous MgSO4 is 1.570 grams. 1. Calculate the moles of H20 removed and the moles of anhydrous MgSO4 remaining in …
  2. Chemistry

    What would be the mass of a bag of anhydrous magnesium sulfate, MgSO4, if it contained the same amount of magnesium as a 1.00kg bag of Epsom Salts, MgSO4 . 7H2O?
  3. Chemistry

    When dilute nitric acid was added to a solution of one of the following chemicals, a gas was evolved. This gas turned a drop of limewater, Ca(OH)2, cloudy, due to the formation of a white precipitate. The chemical was.... a. the household …
  4. ap chemistry

    The formula for epsom salt is MgSO4 . 7H20 If 1.250 g of the compound is dissolved in water, calculate the number of milliliters of .200 M Ba(NO3)2 that would be required to precipitate all of the sulfate ions as barium sulfate. Do …
  5. chemistry

    What would be the mass of a bag of anhydrous magnesium sulfate, MgSO4, if it contained the same amount of magnesium as a 1.00kg bag of Epsom salts, MgSO4 x 7H2O?
  6. chemistry

    What is the formula weight for Epsom salt?
  7. chemistry

    I need help with this lab. Write the equation for the decomposition of the hydrate, CuSO4*XH2O. Mass of crucible and hydrate: 93.000g Mass of crucible and pure salt: 91.196g I need to calculate the following: 1. mass of water in hydrate …
  8. Chemistry

    A student analyzing 2.000g of Epsom Salt found that it contained 39.0% by mass water. What is the hydration number for this sample?
  9. chemistry

    Epsom salts, a strong laxative used in veterinary medicine, is a hydrate, which means that a certain number of water molecules are included in the solid structure. The formula for Epsom salts can be written as MgSO4 ยท x H2O, where …
  10. Chemistry college

    You are given a recipe for a buffer that contains 5% (w/v) MgSO4.7H2O. However, you only have MgSO4 anhydrous available to you. How much MgSO4 anhydrous do you need to make 0.5L of the buffer with the same molar concentration as in …

More Similar Questions