so I have this chemistry problem which involves math and basically I need to convert 62 g/mol into mol/L but I don't know how.
like do you DIVIDE the g/mol by 1000 to convert g to L? and then how to you get the mol to become the numerator?
there are 1000 cubic centimeters which is 1000 grams of water (close enough) in a liter
which is 10 cm * 10 cm * 10 cm
now I do not know what chemical you are using that is 62 grams/mol
You better give me the whole problem carefully because unless you know M, the molarity, you can not go from grams/mol to grams/liter
molarity is mols/liter
and
62 grams/mol means 6*10^23 molecules has mass of 62 grams
oh, sorry! yes, M= 62g/mol in my case and I need to go from there to mol/L.
and the question is: The solubility of magnesium fluoride, MgF2(s), is 1.72x10^-3 g/100mL at 25 degrees. What is the Ksp value for Magnesium fluoride at 25 degrees?
I am just plodding through this
http://www.khanacademy.org/science/chemistry/acid-base-equilibrium/copy-of-solubility-equilibria-mcat/v/solubility-product-constant-from-the-solubility
Solubility MgF2 = 1.72E-3 g/100 mL. The molar mass is closer to 62.3 than to 62.
mols = g/molar mass = 1.72E-3/62.3 = 2.76E-5 mols amd that is in 100 mL; therefore, M = 2.76E-5 mols/0.1L = 2.76E-4.
.......MgF2 ==> Mg^2+ + 2F^-
I......solid....0........0
C......solid....x.......2x
E......solid....x.......2x
Ksp = (Mg^2+)(F^-)^2
(Mg) = x molar from above.
(F^-) = 2x molar from above.
Ksp = (x)(2x)^2 = 4x^3
Substitute the solubility (from above) of 2.76E-4 M and calculate Ksp at 25 C.
Already on it. :-)
thank you dr.bob and damon! :)
To convert from g/mol to mol/L, you cannot directly divide g/mol by 1000 to convert grams to liters. Instead, you need additional information to convert from g/mol to mol/L.
The unit g/mol represents the molar mass of a substance, which is the mass of one mole of that substance. So, to convert g/mol to mol/L, you need to know the density or volume of the substance.
Here's the step-by-step process:
1. Identify the substance for which you want to convert g/mol to mol/L.
2. Determine the density of the substance or the volume it occupies in liters. Let's say the density is given as 1.5 g/mL.
3. Convert the given density to g/L by multiplying by 1000 (since there are 1000 mL in one liter). In this example, the density would be 1500 g/L.
4. Divide the molar mass (62 g/mol) by the g/L value obtained in the previous step. It gives you the conversion factor from g/mol to mol/L.
- Convert 62 g/mol to mol/L: 62 g/mol รท 1500 g/L = 0.04133 mol/L
So, in this case, the conversion factor for the substance is approximately 0.04133 mol/L. Multiply this conversion factor by any value in g/mol to get the corresponding value in mol/L.
Remember, the conversion from g/mol to mol/L depends on the density or volume of the substance. If that information is not provided, you will need additional data to perform the conversion accurately.
so
you have
1.72 * 10^-3 g /100 mL
which is
17.2 * 10^-3 g/liter ten times as much because 1000mL is 1 liter
how many mols is 17.2 * 10^-3 g
17.2*10^-3 g/L / 62 g/mol
= .277 * 10^-3 mol/Liter
2.77 *10^-3 mols/Liter or M
Now to get from there to Ksp
I suggest looking at
https://www.khanacademy.org/science/chemistry/acid-base-equilibrium/copy-of-solubility-equilibria-mcat/v/solubility-product-constant-from-the-solubility
you have Mg ++
and 2 F-