posted by .

i don't really understand molality. I know that it is a big concept but could someone explain it a little.

the question is how would you prepare a molality solution.


    Molarity is about as simple as it gets. The definition is all you need.
    The definition of molarity is
    Molarity = M = # moles/Liter of solution.
    So, to prepare a 1 molar solution, of something, say NaCl, you dissolve 1 mole of NaCl in water, shake it around until all of it dissolved, then make the final volume of the solution to 1 L. Simple, eh what? A 2 molar solution you dissolve 2 moles of NaCl in ......, a 3 M by dissolving 3 moles NaCl.... etc.
    What is a mole of NaCl? moles = g/molar mass. So 1 mol of NaCl is about 23 for Na and about 35.5 for Cl or about 58.5 grams for a mole NaCl. (You can look up Na and Cl on the periodic table and get the exact mass if you want it). Since M = mols/L, that can be rearranged to make M x L = moles and L = mols/M.
    Please let me know if this doesn't do the job BUT be sure and tell me exactly what is still unclear about it.


    thanks i didn't really get molarity either but my question is for molality.


    I didn't answer your original question because it makes no sense. There is no such thing as preparing a molarity solution. You can prepare a MOLAR solution or a TWO MOLAR solution but you can't prepare a molarity solution. You CAN add an maount of material to a certain amount of water and ask for the molarity of that solution and it's th same concept. Its mols/L = Molarity. So if you are given 29.25 g NaCl in a final volume of 500 mL (0.50 L), then the solution is M = moles/L. We have 29.25 grams NaCl which is 20.26/58.5 = 0.500 g in 0.500 L = 0.5/0.5 = 1 M.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chem

    how do u set up with problem How would you prepare 165 mL of a 0.0317 m solution of benzoic acid (C7H6O2) in chloroform (CHCl3)?

    A bottle of wine contains 13.1% ethanol by volume. The density of ethanol (C2H5OH) is 0.789 g/cm3. Calculate the concentration of ethanol in wine in terms of mass percent and molality. i don't know how to get molality. please help!!!! …
  3. Chemistry

    What is the molality of a glucose solution prepared by dissolving 18.0g of glucose, C6H12O6 in 125g of water?
  4. Chemistry

    Hello Jiskha, I'm hoping you are able to help me with my homework. Its on General Chemistry. Question One - When the solid NH4NO3 is dissolved in water at 25 C, the temperature of the solution decreases. What is true about the signs …
  5. Chemistry

    How would you prepare 1.00L of 0.13m solution of sugar, C12H22O11?
  6. Physical Chemistry

    Calculate the concentrations of each of the following solutions. (a) the molality of chloride ions in an aqueous solution of iron(III) chloride for which xFeCl3 is 0.0195 (b) the molality of hydroxide ions in a solution prepared from …
  7. chemistry

    what is the molality of a 10.5% by mass glucose solution?
  8. Chemistry

    An aqueous solution of ethanol is 14.1M C2H5OH. The density of the solution is 0.853g/mL. What is molality of ethanol in the solution?
  9. chemistry

    this is a really long question. i don't understand how to answer it. help please. A 10.0% aquueous solution of sulfuric acid has a density of 1.0661 g/mL at 20 degrees celsius. A. how many grams of H2SO4 are found in 50.0 g of this …
  10. chemistry

    State how you would prepare each solution: 1) 455g of a solution of C3H5(OH)3 in water in which the mole fraction of glycine is .250 2) 755g of 1.4 molality solution of napathalene C10H8 in benzene C6H6. My instructor told us to find …

More Similar Questions