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.
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.
To make a 100mL 0.500M solution of NaOH using the given resources, you can follow two different methods:
Method 1: Dilution using solid NaOH and water
Step 1: Calculate the number of moles of NaOH needed for a 0.500M solution using the formula:
Moles = Molarity × Volume (in liters)
Moles = 0.500 M × 0.100 L = 0.050 moles
Step 2: Determine the mass of solid NaOH required using its molar mass:
Mass = Moles × Molar mass
Mass = 0.050 moles × 40.00 g/mol = 2.00 grams
So, for this method, you need to measure 2.00 grams of solid NaOH.
Step 3: Dissolve the measured 2.00 grams of solid NaOH in a container by adding a small amount of water and stirring until it completely dissolves.
Step 4: Once the solid NaOH is dissolved, transfer the solution to a 100 mL volumetric flask using a funnel. Top up with distilled water until the solution reaches the 100 mL mark on the volumetric flask.
Method 2: Dilution using a concentrated NaOH solution (2.0M)
Step 1: Calculate the volume of the concentrated 2.0M NaOH solution required using the formula:
Volume = (Moles × Molar volume) / Molarity
Molar volume = 22.4 L/mol at STP (standard temperature and pressure)
Volume = (0.500 M × 0.100 L) / 2.0 M = 0.025 L = 25 mL
For this method, you need to measure 25 mL of the 2.0M NaOH solution.
Step 2: Transfer the measured 25 mL of the 2.0M NaOH solution to a 100 mL volumetric flask using a pipette or graduated cylinder.
Step 3: Top up the volumetric flask with distilled water until the solution volume reaches the 100 mL mark on the flask.
Both methods will give you a 100 mL 0.500M NaOH solution using the given resources.