Question

1. Calculate the volume in milliliters (mL) of a 6.00 M NaOH solution needed to make 5.00 x 102 mL of a 0.100 M NaOH solution. (Recall that M = molar = mol/L, and show all your work).

2. An approximately 0.1 M NaOH solution was standardized with KHP by titration to a phenolphthalein endpoint. From the following data, calculate the average molarity of the NaOH. The molar mass of KHP is 204.22 g/mol.

Trial 1 Trial 2 Mass of weighing paper + KHP 2.1467 g 2.1719 g Mass of weighing paper 1.4125 g 1.4136 g Mass of KHP __________ __________ Moles of KHP __________ __________ Final buret reading 31.80 mL 32.67 mL Initial buret reading` 0.15 mL 0.04 mL Volume of NaOH (mL) __________ __________ Molarity of NaOH (moles per liter) __________ __________ Average molarity __________

3. Calculate the average molarity, standard deviation (SD), and percent (%) variation of the three titration molarities given below. Recall: % variation = (SD/mean)*(100%).

Molarity of HCl: 0.3087 M 0.3083 M 0.3092 M

Average Molarity: ___________________ ± _____________ (SD) [UNITS!]

Percent (%) variation: ____________________ %

Is the percent variation less than 1%? _________

Answer 1