1. Is it possible to obtain 2 liters of a solution of NaOH (Mw = 40) 1 M by diluting a solution containing 0,2 grams of NaOH in 100 ml of solution ?
2. How many water you have to add to 450 ml of a solution 0.3 M to obtain a solution 0.25 M ?
3. The molecular weight (mw) of HCl is 36, calculate: i) the grams of HCl contained in 0.2 moles; ii) the grams of HCl needed to prepare 500 ml of a solution 1 M.
4. 500 ml of a solution contains 20 grams of NaOH (mw = 40). Calculate the molarity of the solution.
5. A solution of NaOH (mw = 40) is prepared by dissolving 20 grams of the base in enough water to make one liter of solution. Calculate the molarity of this solution.
6. Calculate the grams of NaCl (mw = 58) contained in 30 ml of a 0.2 M solution.
7. 2 liter of a solution contain 1 mole of HCl. Calculate the molarity of the solution.
8. Calculate the grams of HCl (mw = 36) present in two liter of a solution 0.3 M.
9. Calculate the ml of a 1 M solution of NaCl needed to prepare 100 ml of a 0.2 M solution.
10. How many grams of Na2SO4 (Mw = 142) are needed to prepare 5 liters of a solution 0.1 M ?
11. Calculate the concentration expressed in grams% (w/v) of a 1 M solution of HCl (Mw=36).
12. You need to withdraw 200 grams of a KCl solution having density = 1.16 g/ml. How many ml of the solution you will withdraw ?
13. Calculate the molarity of a solution containing 100 gr of NaCl (Mw = 58.5) in 1.5 liters of water.
14. One liter of a solution 6 M HCl is to be prepared by mixing two different solutions of the acid:
1. HCl 12 M
2. HCl 3 M
Assuming that there is no variation of the volume during the mixing, calculate the ml of solution 1 and solution 2 to be mixed.
15. The preparation of 300 ml of a 10% (w/v) solution of NaCl is to be accomplished by mixing two different solutions of the salt:
1. NaCl 5%
2. NaCl 20%
Assuming that there is no variation of the volume during the mixing, calculate
the ml of 1 and 2 needed.
16. Potassium permanganate (KMnO4) reacts with oxalate ion (C2O4--) according to the following reaction:
2MnO4- + 5C2O4-- + 16H+ = 2Mn++ + 10CO2 + 8H2O
Calculate the milliliters of 0.10 M KMnO4 that react completely with 0.01 moles of oxalate.
17. Calculate the density of a solution obtained by mixing 150 ml of NaOH (d = 1.70 gr/ml) and 350 ml of distilled water (d = 1 gr/ml).
18. When 300 ml of water are added to 100 ml of H2SO4 solution (d = 1.2 g/ml) a contraction of the volume of 4% is observed. Calculate the density of the final solution.
19. A solution of HNO3 is 20% by weight (i.e., 20 g of acid in 100 g of solution) and has a density of 1.11 gr/ml. Calculate which volume of the solution contains 10 g of HNO3.
20. A solution of H2SO4 (density = 1.834 gr/ml) contains 95 g of the acid per 100 grams of solution. Calculate the volume of the solution containing 38 gr of the acid.
21. A solution of KOH (density = 1.4 gr/ml) was obtained by mixing 100 ml of a solution of KOH (density = 1.5 gr/ml) with 100 ml of another solution having density = 1.1 gr/ml. Calculate the volume of the resulting solution.
22. A solution of NaCl was obtained by mixing two different solutions of the salt:
1. one liter of a solution containing 1.8 g/100 ml of solution
2. 750 ml of another solution containing 3.3 g/100 ml of solution.
Calculate the concentration of the resulting solution expressed as grams/100 ml of solution.
23. Calculate the molality and molarity of a solution of ethanol in water, by knowing that the mole fraction of ethanol is 0.05 and the density of the solution is 0.997 grams/ml.
24. Calculate the weight of a solution prepared by mixing:
200 ml of a solution of HNO3 (d = 1.48 g/ml)
200 ml of a solution of H2SO4 (d = 1.9 g/ml)