شرح درس
Concentration of Solutions
CHEMISTRY - Secondary 1
In This part we will study
Examples:
 Calculate the mass percentage (m/m) of the solution produced from dissolving 10 g of sucrose in 240 g of water.
 Calculate the volume percentage (V/V) of the solution produced from the addition of 25 mL of ethanol to an amount of water to form 50 mL of the solution.
 Molarity (M):
Molarity: Is the number of moles of solute dissolved in one liter of solution.
 Molality (m):
Molarity: It is the number of moles of solute in one kilogram of solvent.
The unit of molality is (mol/kg) or (m).
Example (1):
Calculate the molarity for 85.5 g cane-sugar C12H22O11 in a certain amount of water to form 0.5 L of solution. [C = 12 , H = 1 , 0 = 16]

Example (2):
Magnesium reacts with hydrochloric acid, according to the equation:
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
Calculate the volume of 1.5 M hydrochloric acid which is required to react completely with 17.28 g of magnesium (at STP). [Mg = 24 , H = 1 , Cl = 35.5]

Example (3):
Calculate the molality of a solution prepared by dissolving 20 g of sodium hydroxide NaOH in 800 g of water. [Na= 23, O = 16, H = 1]

Example (4):
Calculate the concentration of a solution produced from mixing 1 g of ethanol C2H5OH with 99 g of water H2O, expressed by:
(a) The mass percentage.
(b) Molality.
Solution:

Example (5):
Calculate the concentrations of the cations and the anions in 0.4 M (NH4)2Cr2O7 solution.

Best wishes to you
Mr.Ahmed Elbasha

كيمياء الصف الاول الثانوي لغات - الفصل الدراسي الاول
شرح كيمياء لغات اولي ثانوي - مستر احمد الباشا
كيمياء لغات - الصف الاول الثانوي - كيمياء اولي ثانوي الترم الاول - كيمستري اولي ثانوي الترم الاول