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Question 1 of 3

What is the molarity of a solution containing 1.07 moles of Succinic Acid in 1225 cm3? Answer to 4 significant figures.

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M
The solution is 0.8735 M Succinic Acid to 4 significant figures.

Molarity = Number of Moles
Volume in dm3

1225 cm3 = 1.225 dm3
Molarity of Succinic Acid =    1.07    moles/dm3
1.225
Molarity of Succinic Acid = 0.87346 moles/dm3
Molarity of Succinic Acid = 0.8735 moles/dm3 to 4 sig figs

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Question 2 of 3

A pharmacist weighs out 37.25 grams of Potassium Chloride (RMM 74.5) and makes a solution up to 150 cm3 with water. What is the molarity of the solution to 4 significant figures?

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M
The solution is 3.333 M Potassium Chloride to 4 significant figures.
Molarity = Number of Moles
Volume in dm3
  1. Find the number of moles of Potassium Chloride present.
    Moles of KCl = Mass/RMM = 37.25/74.5 = 0.5 moles
  2. Convert the volume in cm3 to dm3 .
    150 cm3 = 0.15 dm3
  3. Find the molarity of Potassium Chloride in the solution.
    Molarity of Potassium Chloride =    0.5    moles/dm3
    0.15

Molarity of Potassium Chloride = 3.3333 = 3.333 moles/dm3 to 4 sig figs

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Question 3 of 3

Physiological or normal saline contains 0.9 grams of Sodium Chloride in 100 cm3 of solution. What is the millimolarity of physiological saline to 4 significant figures?

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mM
Physiological saline is 153.8 mM Sodium Chloride to 4 significant figures.
Millimolarity = Number of millimoles
Volume in dm3
  1. Find the number of millimoles of Sodium Chloride present.
    Moles of NaCl = Mass/RMM = 0.9/58.5 = 0.015384 moles
    Millimoles of NaCl = Moles x 1000 = 0.015384 x 1000 = 15.384 millimoles
  2. Convert the volume from cm3 to dm3 .
    100 cm3 = 0.1 dm3
  3. Find the millimolarity of Sodium Chloride.
    Millimolarity of Sodium Chloride = 15.384 millimoles/dm3
    0.1
    Millimolarity of NaCl = 153.84 = 153.8 millimoles/dm3 to 4 sig figs
Physiological saline has the same osmotic pressure as body fluids.

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