Question

Please help me in this 2 questions I finish my whole post lab question but I been stuck 3 days in this two question. I will like to know how to do them please.

b. Calculate the number of grams of potassium chloride in 1 drop of 0.10M KCl solution.

9. How many grams of sodium Chloride are require to prepare 350mL of 0.15M NaCl solution?Show calculations.

Answer 1

b. Calculate the number of grams of potassium chloride in 1 drop of 0.10M KCl solution.

Generally 1 drop of an aqueous solution has a volume = 0.05 mL

So we can say volume of KCl solution taken = 1 drop = 0.05 mL

Concentration of KCl solution taken = 0.10M KCl

That means mols of KCl present = concentration * volume

= 0.10M * 0.05 mL

= 0.10 mol/ 1000 mL * 0.05 mL

= 0.000005‬ mol

That means mass of KCl present = moles * molar mass of KCl

= 0.000005‬ mol * 74.55 g/mol

= 0.00037 g

9. How many grams of sodium Chloride are require to prepare 350 mL of 0.15 M NaCl solution?

Similarly given

volume of NaCl solution taken = 350 mL

Concentration of NaCl solution taken = 0.15 M KCl

That means mols of NaCl present = concentration * volume

= 0.15 M * 350 mL

= 0.15 mol/ 1000 mL * 350 mL

= 0.0525‬ mol

That means mass of NaCl present = moles * molar mass of NaCl

= 0.0525‬ mol * 58.44 g/mol

= 3.068 g

So 3.068 g of NaCl is required to prepare 350mL of 0.15M NaCl solution