[Nikky Wong]

30. What are the molarities of the constituent ions if 25.0 g of sodium carbonate-10-water crystals(Na₂CO₃·10H₂O) are dissolved in distilled water and made up to 250.0cm³?
(Relative atomic masses: H=1.0, C=12.0, O=16.0, Na=23.0)

31. You are given 25.0cm³ of 11.0 M HCl(aq). Calculate the molarity of the newly prepared HCl if the following volumes of distilled water are added successively:
(a) 25.0cm³
(b) 75.0cm³
(c) 100cm³

32. (a) What volume of distilled water is needed to dilute 45.0 cm³ of 0.65 mol dm^-3 HNO₃(aq) to 0.45 mol dm^-3
(b) The distilled HNO₃(aq) in (a) is left uncovered for three hours, 30.0cm^-3 of the HNO₃(aq) remains. What is the molarity of this solution?

33. A commercial ammonia called '0.68 ammonia' has a density of 0.68 g cm^-3 and contains approximately 34% of ammonia by mass.
(a) Calculate the mass of ammonia present in 1 dm³ of the solution of this commercial ammonia.
(b) Calculate the molarity of this solution.
(c) Calculate the volume of distilled water added if the solution has to be diluted to 1 mol dm^-3.
(Relative atomic masses: H=1.0, N=14.0)

34. A student is going to prepare a 250.0 cm³ solution of oxalic acid from its pure crystals((COOH)₂·2H₂O). He weighs out 1.8 g of oxalic acid crystals and dissloves them in 25.0 cm³ of distilled water. Then the solution is diluted to 250.0 cm³.
(a) Calculate the number of moles of oxlic acid obtained from 1.8 g of its crystals.
(b) Calculate the molarity of the 25.0 cm³ solution of oxalic acid.
(c) Calculate the molarity of the soultion of oxalic acid after it has been diluted to 250.0 cm³.

[billnotgatez]

Forum rules require you show attempts at solving
you showed solving attempts before on other posts by posting your thoughts in red
in the future you should do the same
for this post just reply with your attempts
good luck