Question

You have been asked to prepare an 8.50M solution of sodium hydroxide, NaOH in a 250mL volumetric flask. How many grams of solute will you have to mass on the balance?

Answer 1

Data:
M (molarity) = 8.50 M
m (mass) = ? (in grams)
V (volume) = 250 mL → 0.25 L
MM (Molar Mass) of Sodium Hydroxide
Na = 1*23 = 23 amu
O = 1*16 = 16 amu
H = 1*1 = 1 amu
------------------------------------
MM of NaOH = 23+16+1 = 40 g/mol

Formula:


`M = (m)/(MM*V)`

Solving:

`M = (m)/(MM*V)`

`8.50 = (m)/(40*0.25)`

`8.50 = (m)/(10)`

`m = 8.50*10`

`\boxed{\boxed{m = 85\:g}}\end{array}}\qquad\quad\checkmark`

Answer:
85 grams