explain two different ways you could make 100ml of .500M solution of NaOH if you have an unlimited amount of water, 100g solid NaOH and a bottle of 2.0M NaOH.

Answer 1

1. Use the solid.
How many moles do you want? That's M x L = 0.5 x 0.100 = 0.05
How many grams is that? mols = grams/molar mass or
grams = mols x molar mass = 0.05 x 40 g/mol = ?
Weigh ? grams NaOH, place in a 100 mL volumetric flask, add some water, swirl to dissolve, add water to the mark of the flask, mix thoroughly, cap, label.

2. Use the 2.0 M solution.
mL1 x M1 = mL2 x M2
100 x 0.5 = mL2 x 2
Solve for mL2, pipet that amount of 2.0 M NaOH solution into the 100 mL volumetric flask, add water to the mark on the flask, mix, cap, label.