QUESTION 21
Sam weighed out 49.99g of sodium hydroxide (NaOH). The final volume of his solution is 750mL. What is the molarity of Sam's working stock of NaOH? The MW of NaOH is 39.99.
1.67M?
molarity=49.99/(39.99(.750))=1.67
To find the molarity of Sam's working stock of NaOH, we need to use the formula:
Molarity (M) = moles of solute / volume of solution (in liters)
First, let's calculate the moles of NaOH:
moles of NaOH = mass of NaOH / molar mass of NaOH
mass of NaOH = 49.99g
molar mass of NaOH = 39.99g/mol
moles of NaOH = 49.99g / 39.99g/mol = 1.250 mol
Next, let's convert the volume of the solution from milliliters (mL) to liters (L):
volume of solution = 750 mL = 750/1000 L = 0.750 L
Now we can substitute the values into the formula to find the molarity:
Molarity (M) = 1.250 mol / 0.750 L = 1.67 M
So, the molarity of Sam's working stock of NaOH is indeed 1.67 M.