Question

2. Show all work (2 pts), units on every number that has units (1 pt), and the correct answer (2 pt) A relatively old container of NaOH (MW: 39.997 g/mol) pellets is used to make a -0.1 M solution. 2.00 g of the solid NaOH is weighed out, dissolved into water and diluted to a total solution volume of 500.0 mL. The NaOH solution is standardized using KHP (204.22 g/mol). It takes 15.90 mL of the NaOH solution to titrate a solution containing 0.3004 g of KHP to the endpoint. Assuming water is the only contaminant in the NaOH pellets, calculate the % by mass of water contamination in the solid NaOH pellets.

Answer 1

Your answer! The balanced equation for the reaction between - KHP and nach is KEP+ NaOH MakP+Ho- Mo. of moles of KHP = wt. Mo. of moler of K HP = Motot. 0.3004 g 20.001441 204. 22g/ml Based on equal, according to stoichiometing mole of KHP reacts with Imole of NaOH ..0.001471 mol kHP reacts also with 0.001471 mol pla 2. No. of moles of NaOH = 0.0014 # nol. Mass (wt.) y NaOH = moles x mol.wt igpach = 0.001471 % 39.997 g/mol = 0.0588359. It takes 15.90 mL of Nach Solu- to reach and point. mo That means, Mass of NaOH in 15.90 mL of solution = 0.058835g. Mass of Naoth in 500 mL of solution = 0.0588358500 not in 500 mL of 15.90 a 1.850157 g. Mass of wat Alaot in 2.00g of Solid HaOH = 1.8501579 .. Mass of water z 2.00 -1.850157 = 001498439 Mass percent of water contamination 0:149843 $ x 100 = 17491. 2500 g CScanned with CamScanner