please help, how many milliliters of a .100 solution of NaOH would be needed to contain 2 g of NaOH?

Question

please help, I tried doing this problem and I am not sure how it is supposed to be set up. Thanks

Answer 1

If this is in Normality;

0.1 Normal solution of NaOH
2 grams of NaOH in a liter = 0.05 N

N = weight in grams divided by MW (molecular weight ) = 40 / valence =1 / 1 liter. = 0.05

MW = (Sodium) 23 + 16 (Oxygen) + 1 (hydrogen) = 40

Therefore: Using the formula N1V1 = N2V2
(0.1)( X) = (0.05) ( 1 liter)

By cross multiplication:

X = (.0.05) ( 1) divided by ( 0.1)
X = 0.5 liters or 500 milliliters

because 1,000 ml = 1 liter

You will get the same answer for Molarity because the valence is one.

so the answer is 500 milliliters.

Answer 2

1) 2g NaOH x (1 mole NaOH / 40g) -->this is the molar mass of
NaOH---> This gets 0.05mol NaOH.
2) 0.05mol NaOH x (1 L / 0.100mol) = 0.5L --> this is your volume
3) CONVERT TO MILLILITERS!!! 0.5L x (1000 mL / 1L) = 500mL

The concept in the first step is finding the molar mass of the whole compound from the mass of each individual element on the periodic table and adding them together. (i.e. Na=23g/mol, O=16g/mol, H=1g/mol ---> 23+16+1=40g/mol for NaOH)

The concept in the second step is realizing that the molarity that they give you can be used as a conversion factor. Recall: molarity is measured in moles per liter, so you have 0.100 mol/L.

And the third step is probably designed to screw you up because the first answer you get will be in liters, and if you report that answer, you are wrong, so remember to answer what the problem asks, in this case, convert to milliliters by using the conversion facts 1000mL/1L.

Hope this helped...

Answer 3

.1N solution of NaOH contains 0.1x40gm of NaOH in 1litre.
here 40 is the molecular weight of NaOH.
Hence for 2g you have to take 500ml.