Question

12. Molarity, M, is defined as A. moles of solute dissolved in 1 mol of solvent. B. moles of solute dissolved in 1 kg of solvent. C. moles of solute dissolved in 1 L of solvent. D. moles of solute dissolved in 1 L of solution. E. moles of solute dissolved in the solution. 13. What volume of 2.50 M NaOH (40.00 g/mol) contains 0.100 mole of NaOH? A. 0.250 L D. 0.250 mL B. 40.0 mL E. 0.0400 mL C. 25.0 mL 14. How many grams of sodium chloride (NaCl, 58.44 g/mol) are needed to make up 250 mL of a solution that is 2.00 M? 4.28 g D. 29.2 g B. 7.30 g E. 117 g C. 14.6 g 15. How many grams of solid potassium chlorate (KCIO3, 122.55 g/mol) are needed to make 150 mL of 0.50 M solution? A. 0.11 g B. 37 g C. 9.2 g D. 0.41 g E. 2.7 x 102 g 16. In the dilution of 10.0 mL of a 0.10 M solution of HCl to a volume of 20.0 mL, what remains unchanged? A. the mass of the HCl solution D. the moles of HCl in the solution B. the concentration of the HCl solution E. All of the above change. c. the volume of the HCl solution 17. What volume of 12.0 M HCl solution needs to be diluted to produce 500.0 mL of 3.00 M HCI solution? A. 0.125 L B. 0.250 L C. 0.500 L D. 2.00 L E. 1.00 L

Answer 1

12)

Molarity = mol of solute / volume of solution in L

Answer: D

13)

Molarity = mol of solute / volume of solution in L

2.50 M = 0.100 mol / volume

Volume = 0.040 L

=40.0 mL

Answer: B

14)

volume , V = 250 mL

= 0.25 L

use:

number of mol,

n = Molarity * Volume

= 2*0.25

= 0.5 mol

use:

mass,

m = number of mol * molar mass

= 0.5*58.44

= 29.22 g

Answer: D

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