NUMERICAL PRACTICE

DAY 3
23.4.20

GOOD MORNING BOYS,
Today we will have assesment of topics covered in the form of MCQ through google form, after that we will cover the topics of limiting reagent and methods of expressing concentration.

FIRST ATTEMPT THE MCQ .




  LEARNING OUTCOMES;

Students will be able to

• Define limiting reagent
• Apply concept
• learn different methods of expressing concentration.

Limiting Reagent:

It is the reactant which  gets consumed first or limits the amount of product formed.

For a balanced reaction reaction:

                                    A +B →  C + D

B would be a limiting reagent if n_A /n_B > n_B/n_A

Similarly, A is a limiting reagent if n_A /n_B < n_B/n_A

Concentration of the solutions

Mass Percent:

• It is the mass of the solute in grams per 100 grams of the solution.
• 

Volume Percent:

• It is the volume of the solute  per 100 units of the volume of solution.
• 

Parts per million ( ppm):

• It is the amount of the solute in gram per million (10⁶) gram of the solution.
• 

Mole fraction:

• It is the ratio of the moles of one component of the solution to the total number of moles of solution
• Total mole fraction of all the components of a solution is equal to 1.

Molarity (M):

•  It is the number of moles of solute dissolved per litre (dm³) of the solution.
• 

Molality (m):

• It is the number of moles of solute present in 1 kg of solvent.
• 

Note: Why m is not affected by change in temperature?

Since it is dependent on mass of solute and mass do not change to small shift in temperature due to close packing of solid atoms therefore it is independent of temperature change.

video to revise mole concept, percentage composition and empirical formula

Numerical practice :

What is the molarity of a solution containing 0.32 moles of NaCl in 3.4 liters?

Solution:



            = 0.94 M NaCl

What is the molarity of a solution containing 0.46 mole of solute in 2.0 kg water?

Solution:





= 0.23 m

THATS ALL FOR THE DAY, WE WILL CONTINUE WITH NUMERICAL PRACTICE IN OUR NEXT THEORY CLASS.

STAY SAFE AND TAKE CARE.

MARK YOUR ATTENDANCE ON GOOGLE FORM AS WELL AS COMMENT SECTION OF BLOGGER.