What are the units of Molarity? How many grams of NaOH are needed to make 0.5 L of .25 M NaOH Solution? How do I do this problem?
2007-11-13 16:57:00 · 1 answers · asked by Christine O 1 in Science & Mathematics ➔ Chemistry
Molarity = moles/liter
NaOH (aka caustic soda) comes in pellets and is very hydroscopic (absorbs water right out of the air or even your skin). It has a formula weight of 40g/mole, that means if you have 40g of this, you have 1 mole. If you were to make a liter of 1M NaOH, you'd need to dissolve 40g into 1 liter of water. If you're only making 0.5 liters of a 1M solution, you'd just dissolve 20g into 0.5 liters. If you're only making 0.5 L of a 0.25M solution, then you'd dissolve 5g into 0.5 L.
40g/L X 0.5L X 0.25mol/L = 5g/L
2007-11-13 17:00:14 · answer #1 · answered by BP 7 · 5⤊ 0⤋
Molarity Units
2016-09-28 06:43:56 · answer #2 · answered by ? 4 · 0⤊ 0⤋
Just work it out stepwise...
Molarity = mols/liter = the number of molecular weights of a solute contained in one liter of solution.
MW of NaOH is 40.0
To make one liter of 1.00M soln would require 40.0g NaOH
To make one liter of 0.25M soln would require 10.0g
To make 0.5 liters of 0.25M soln would require 5.0g NaOH dissolved in enough water to make 500ml of soln.
One step at a time avoids confusion :-))
2007-11-13 17:29:12 · answer #3 · answered by L. A. L. 6 · 0⤊ 0⤋
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Yeah mol/mL, but I'd just divide by 1000 and use M or mol/L.
2016-03-26 22:41:56 · answer #4 · answered by Anonymous · 0⤊ 0⤋