Question

1. Calculate the molarity of the following solutions: a. 318 g Mg Br, in 859 ml solution b. 8.28 g Ca(C,H,O,), in 414 ml solution c. 31,1 g Al,(80.), in 766 ml solution d. 59.8 g CaCl, in 100 ml solution e. 313.5 g LICIO, in 250 ml solution | 849 Calculate the moles of solute needed to prepare each of the following: 2. LOL of a 3.0 M NaCl solution b. 0.40 L of a 1.0 M KBr solution e. 125 ml of a 2.0 M MgCl, solution 8.50 Calculate the moles of solute needed to prepare each of the following: a. 5.0 L of a 2.0 M CaCl, solution b. 40 L of a 0.10 M NaOH solution c. 215 mL of a 4.0 M HNO, solution 11.51 Calculate the grams of solute needed to prepare each of the following: a. 2.0 L of a 1.5M NaOH solution 4.0 L of a 0.20 M KCl solution c. 25.0 mL of 6.0 M HCl solution 8.52 Calculate the grams of solute needed to prepare each of the following: a. 2.0 L of a 6.0 M NaOH solution b. 5.0 L of a 0.10 M CaCl, solution c. 175 ml of a 3.00 M NaNO, solution 8.53 What volume is needed for each of the following: a. liters of a 2.0 M NaOH solution to obtain 3.0 moles of NaOH b. liters of a 1.5 M NaCl solution to obtain 15 moles of NaCl c. milliliters of a 0.800 M Ca(NO3)2 solution to obtain 0.0500 moles of Ca(NO3)2 8.54 What volume is needed for each of the following: a. liters of 4.0 M KCl solution to obtain 0.100 mole of KCI b. liters of a 6.0 M HCl solution to obtain 5.0 moles of HCI c. milliliters of a 2.5 M K SO, solution to obtain 1.2 moles of K SO. 8.55 Calculate the final concentration of each of the following diluted solutions: a. 2.0 L of a 6.0 M HCl solution is added to water so that the final volume is 6.0 L. b. Water is added to 0.50 L of a 12 M NaOH solution to make 3.0 L of a diluted NaOH solution c. A 10.0 mL sample of 259 (m/v) KOH solution is diluted with water so that the final volume is 100.0 mL d. A 50.0-mL sample of 15% (m/v) H.SO, solution is added to water to give a final volume of 250 ml 8.56 Calculate the final concentration of each of the following dilutet solutions: a. 1.0L of a 4.0 M HNO, solution is added to water so that the final volume is 8.0 L. b. Water is added to 0.25 L of a 6.0 M KOH solution to make 2.0 L of a diluted KOH solution

Answer 1

1. Molarity = number of moles of solute/ volume of solution in litres

Number of moles of solute = mass /molar mass

a) moles of MgBr2 = 316/184.113 = 1.716 mol

Molarity = 1.716/0.859 = 2 M

b) moles of Ca(C5H9O2)2 = 8.28/242 = 0.0342 mol

Molarity = 0.0342/0.414 = 0.0826 M

c) moles of Al2(SO4)3 = 31.1/342.15 = 0.0908 mol

Molarity = 0.0908/0.756 = 0.12 M

d) moles of CaCl2 = 59.5/111 = 0.536 mol

Molarity = 0.536/0.1 = 5.36 M

e) moles of LiClO3 = 313.5/90.39 = 3.47 mol

Molarity = 3.47/0.25 = 13.87 M