JEE Advanced Some Basic Concepts of Chemistry Important Questions

Let us tackle this with a real-world example. Say you’ve got to make coffee and you’re told that every cup of coffee requires 1 spoon of coffee powder, 2 spoons of sugar and half a glass of milk. Now you notice that you have a lot of sugar, lots of milk at home, but only 4 spoons worth of coffee powder. You will soon understand that you can only really make a maximum of 4 cups of coffee, regardless of how much excess sugar or milk you have. The coffee powder, in this case, acts as an example of a limiting factor, which sort of “limits” the maximum product you can obtain from the given materials. In chemistry, these are called limiting reagents and one of the reactants in a chemical reaction acts like one.

A mole is something that contains 6.022 X 10²³ of any chemical entity, that entity being atoms, molecules, ions or others. The number 6.022 X 10²³ is known as the Avogadro number based on the Italian scientist, Amedeo Avogadro. The mole is often used as the standard chemical unit in order to quantify chemical substances. The mole also was previously defined as the number of atoms experimentally determined to be found in 12 grams of the Carbon-12 atom. This definition was later modified in and the one in use today is mentioned above.

All the three are nothing but different units of concentration used based on the situation. Considering how similar all these words look, it might be confusing for students to remember what each of them means. Let’s define each of them as simply as possible.

1. Molality: Denoted by ‘m’, it is calculated as the number of moles of solute present in 1 kilogram of solvent.
   
   Formula: Molality (m) = \[\frac{Take\: Moles\: of\: Solute}{Total\: Kilograms\: of\: Solvent}\]

2. Molarity: Denoted by ‘M’, it is defined as the number of moles of solute, divided by the total volume (in litres) of the solution
   
   Formula: Molarity (M) = \[\frac{Total\: Moles\: of\: Solute}{Total\: Litres\: of\: Solution}\]

3. Normality: Denoted by ‘N’, normality is just another ratio that relates the number of equivalents that exists per litre of the solution
   
   Formula: Normality (N) = \[\frac{Number\: of\: equivalents}{1\: L\: of\: the\: Solution}\]

The Le-chatelier’s principle is basically an observation about chemical equilibria and the factors that lead to it, influence it, disturb it, etc. The points worth noting down about Le-Chatelier’s principles are as follows:

• Used to predict the behaviour of a system in equilibrium when changes in temperature, pressure, or concentration are introduced.

• The addition of heat in a chemical reaction at equilibrium will favour the endothermic direction of the reaction, and the opposite is true for the removal of heat.

• An increase in the concentration of reactants will drive the equilibrium to the right, whereas a decrease in the concentration will drive the equilibrium to the left.

That pretty much wraps it up from our side and we really hope you found this article of some use. Students preparing for the JEE advanced and wanting to secure a seat in one of the prestigious IITs must daily focus on preparing all three subjects equally well and this won't come without constant efforts, revision and practice. 

We recommend students solve such important questions on a regular basis so as to ensure that they don't forget or lose touch with the formulas and important concepts that they have learnt over the past two years. Not just for this chapter but Vedantu has you covered from nearly all fronts by providing dedicated articles for every single chapter in your syllabus. We wish every aspirant the best of luck in their preparation as well as for their final exam! Students can get access to all the important questions and topics from the website of Vedantu. The student can visit the website and download the study materials in the PDF format for free from the app and website.