Question

How many grams of NaOH are needed to make a 250.0 mL or a 4.2 M NaOH solution?Group of answer choicesA. 1.05 grams NaOHB. 42,000 grams NaOHC. 42 grams NaOHD. 1050 grams NaOH

Answer 1

Explanation

Given:

Volume = 250.0 mL = 0.250 L

Concentration/molarity = 4.2 M

Required: Mass of NaOH

Solution

Step 1: Calculate the moles of NaOH

C = n/V C is the concentration, n is the moles and V is the volume

n = C x V

n = 4.2 x 250

n = 1050 mol

Step 2: Calculate the mass of NaOH

m = n x M where m is the mass, n is the moles and M is the molar mass

m = 1050 mol x 40.0 g/mol

m = 42000 g

Answer

B. 42,000 grams NaOH