FST Lab 2 (Basic Concept of Analysis and Understand the method for expression of concentration)

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OBJECTIVE: 

  1. To understand the basic concept of chemical analysis

  2. To understand the method for the expression of concentration 

THEORY: 

Chemical Analysis: Chemical analysis is the process of identifying, separating and quantifying the components of a sample to understand its nature and composition.

Types of Chemical Analysis: 

  1. Qualitative Analysis: Qualitative analysis is used to identify the presence or absence of certain chemical compounds or elements in a sample. This method is often used in organic chemistry to identify unknown substances.

  2. Quantitative Analysis: Quantitative analysis is used to determine the amount or concentration of a particular compound or element in a sample.

Concentration: The amount of a substance (solute) present in a specific volume or mass of solution or solvent.

Molarity: Molarity represents a concentration of a solution expressed as the no. of moles per solute/litre of solution.

Molality: No.of moles of a solute per mass(kg) of a solvent.

Normality: No. of equivalents of a solute per litre volume of solution. 

Formality: Formality is a measure of the concentration of a solute in a solution, expressed in terms of the formal concentration of the solute. 

Mole Fraction: Mole fraction is given as the number of moles of a given solute in the solution to the total number of moles in the solution.

Serial Dilution: A serial dilution is the stepwise dilution of a substance in solution, either by using a constant dilution factor, or by using a variable factor between dilutions.

NUMERICALS

  1. How many moles of NaCL are present in 500ml of a 0.1 molar solution?

Moles= Molarity*Volume(ltr)

Moles= 0.1*0.5

Moles= 0.05 moles

  1. What mass of NaOH is required to prepare 250ml of a 0.5M solution?

Amount of solute(moles)= Molarity*vol(litre)

                                            0.5*0.25= 0.125 moles

  1. How to prepare 0.1 molar HCl solution in 500ml distilled water?

X = 0.1 moles* 0.5L

X = 0.05 moles.

  1. Calculate the normality of 0.98g of H2SO4 is prepared in 500 ml of a solution.

Mass of H2SO4= 0.98g

Volumes of Solution= 500ml= 0.5l

Molar mass of H2SO4+ 98gm/mol

Solution:

No.of moles= Mass / Molar mass

                                   0.98g / 98g/mol

            No.of moles= 0.01 mol

            No.of equivalents= No.of moles*2

                                            0.01*2

           No.of equivalents=         0.02 equi

           Normality= No. of equivalents/ Volumes(in litres)

                           =0.02 equi/ 0.5L

           Normality= 0.04N

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