1. NaOH has a MW of 40. A 0.12M solution is made by adding how much NaOH to 100mL of water?
You want how many moles? That is M x L = 0.12 x 0.100 = ?moles NaOH. Then
moles NaOH= grams NaOH/MW NaOH. You know moles and MW, solve for grams NaOH.
To find out how much NaOH needs to be added to water to create a 0.12M solution, we can use the formula:
Molarity = moles of solute / volume of solution in liters
First, we convert the volume of solution from milliliters to liters:
100 mL = 0.1 L
Next, we rearrange the formula to solve for moles of solute:
Moles of solute = Molarity x volume of solution
Moles of solute = 0.12 mol/L x 0.1 L
Finally, we can use the molecular weight (MW) of NaOH to calculate the mass of NaOH needed:
Mass of NaOH = Moles of NaOH x MW
Mass of NaOH = (0.12 mol/L x 0.1 L) x 40 g/mol
Therefore, the mass of NaOH that needs to be added to 100 mL of water to create a 0.12M solution is 0.48 grams.