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0.800 g Sodium hydroxide is added 0.800 g to a beaker Water is added 200 mL to t

ID: 591787 • Letter: 0

Question

0.800 g Sodium hydroxide is added 0.800 g to a beaker

Water is added 200 mL to the beaker

1. Calculate the expected concentration of the sodium hydroxide solution . The molar mass of NaOH is 39.997 g/mol.

2. Calculate and record the expected mass of benzoic acid required to react with 20.00 mL of a 0.100 M sodium hydroxide solution. Record the mass of benzoic acid using three significant digits

100 mL of water is added to a clean Erlenmeyer flask.

The required mass of benzoic acid calculated in question 2 is added to the Erlenmeyer flask. The 100 mL of water should be enough to dissolve the solid benzoic acid.

Explanation / Answer

1.

concentration of the sodium hydroxide solution = (w/M)*(1000/V)

             = (0.8/39.997)*(1000/200)

             = 0.1 M

2. 1 mol NaOH = 1 mol benzoicacid

   no of mol of NaOH = 20*0.1/1000 = 0.002 mol

   no of mol of benzoicacid reacted = 0.002 mol

   mass of benzoicacid = 0.002*122.123 = 0.244 g