Solubility help please..

Question

how do i calculate the molar concentration of the following solution?

3.5 L solution containing 2.2 mol potassium nitrate. (KNO3)

how do i calculate the final molar concentration when the following is mixed?

50.0 mL of 0.20 M NaOH and 50.0 mL of 0.20 M NaOH.

Answer 1

how do i calculate the molar concentration of the following solution?

3.5 L solution containing 2.2 mol potassium nitrate. (KNO3)

Answer: 2.2 mols KNO3/ 3.5 L = 0.63 M KNO3/L.

how do i calculate the final molar concentration when the following is mixed?

50.0 mL of 0.20 M NaOH and 50.0 mL of 0.20 M NaOH.

Answer:

You could go through the exercise of actually calculating this:

1st solution 0.20 Mols/L x 0.050L = 0.010 mols

2nd solution 0.20 mols/L x 0.050L = 0.010 mols

0.010 mols + 0.010 mols = 0.020 mols

0.020 mols/ (0.050L + 0.050L) = 0.20 mols/L or 0.20 M NaOH

OR you could simply realise that when you mix two solutions of the exact same concentration of the same substance, the concentration remains the same. I'm pretty sure THAT answer would actually be preferred to calculating it out, because it demonstrates better understanding.

Answer 2

if u mix equal volume of the solution and normality also same u r totl concentartion will be 0.2MNaOH itself