Question

1. What is the molarity of a 12.6% solution of sodium carbonate with a density of 1.31 g/mL?

2. What is the mass percent of potassium iodide in a 2.89 M solution of KI with a density of 1.27 g/mL?

3. In an experiment similar to your 15.72 mL of a 0.1294 M Ba(OH)2 solution is titrated with 20.00 mL of a HNO3 solution. What is the molarityof the HNO3?

Answer 1

There are multiple questions here . i am allowed to answer only 1 at a time. I will answer 1st one for you. Please ask other as different question

1.
Let the total mass of solution be 100 g
Mass of sodium carbonate = 12.6 % of 100 g = 12.6 g
Molar mass of sodium carbonate= 106 g/mol
number of moles of sodium carbonate = mass/molar mass
                                                                               = 12.6/106
                                                                               =0.12 mol

volume of solution = mass of solution/ density
                                         = 100 g/1.31 g/mL
                                        =76.34 mL
                                        = 0.07634 L

M = number of moles / volume
     =0.12/ 0.07634
      = 1.56 M
Answer: 1.56 M