TEACHER ORIENTATION PROGRAM
DIGITAL DIARY
SUBJECT -CHEMISTRY
TOPIC
-SOLUTION
CONCEPT - DIFFERENT METHODS OF EXPRESSING
CONCENTRATION
DETAILS:------
Methods of expressing concentration of solution(1) Mass percentage
(2) Molarity of solution
(3) Molality of solution
(4) Mole fraction
(1)MASS PERSENTAGE- mass of component per 100 gram of
solution
MASS PERSANTAGE OF COMPONENT=WA/(WA+WB ) X 100
(2)MOLARITY OF SOLUTION-- no. of moles dissoleved in
1litre of solution
Molarity=moles of solute/volume of solution in litres
(3)MOLALITYOF SOLUTION-no. of moles dissolved in 1kg of
solvent
Molality= moles of solute/weight of solvent in kg
(4)MOLE FRACTION-ratio of no. of moles of component to the
total no. of moles .
EVALUATION TOOLS:
CONCEPT: MOLARITY AND MOLALITY
HOMEWORK:
Q1.Define the term molaritiy and molality?
Q2. Which out of molarity and molality will change with
temperature?
Q3. How is the molarity of solution different from molality?
Q4. Concentrated nitric acid used in lab. Is 68% nitric acid by mass
in aq. Solution .what should be the molarity of such sample of acid
if density of solution is 1.504 g/ml
ASSIGNMENT
LEVEL-1
Q1. Define molarity?
Q2. Write the unit of molality?
Q3. If 11g of oxalic acid are dissolved in 500ml of solution ,what
is the mass percentage of oxalic acid in solution ? d = 1.1 g/ml
Q4. Calculate the mass of urea required in making .25 molal
aqueous solution?
LEVEL-2
Q1. Calculate molarity, molality & mole fraction of KI if density
of 20% (m/m) aq. Solution of KI is 1.202g/ml
Q2. A sugar syrup of weight 214.2 g contains 34.2g of sugar
(C12H22O11)
Q3. Which one is better way for the expression of concentration
Molarity or molality?
Q4. Calculate the molarity of pure water (density of water=1g/ml)
LEVEL-3
Q1. How many ml of .1M HCl are required to react completely 1g
mixture of Na2CO3 and NaHCO3 containing equimolar amounts of
two?
Q2. Calculate the molarity of pure water(density of pure
water=1g/ml)?
Q3. The mole fraction of benzene in a solution with toluene is .50.
calculate the mass percentage of benzene in the solution?
Q4. The density of 10% by mass of KCl solution in water is
1.06g/ml . calculate molarity and molality of solution?
PROJECTQ1. Prepare the solution -- M/30 Solution of NaOH
 M/50 solution of oxalic acid
 M/100 Solution of KMnO4
Q2. Calculate the amount required to prepare M/50 Mohrs salt?
REFERENCES--1. MODEREN abc OF CHEMISTRY
2. PRADEEP
3. N.C.E.R.T TEXT BOOK
4. DINESH
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