describe me briefly about mole number and it's numerical solving techniques
Answers
Firstly I have a very fast friend called rajat rawat so it feels like I am answering this to him . Anyways , mole number also called Avogadro's number or constant is a no . It's just a small cute number as any other . Most of the times it frightens the students because it seems to be complex. But , it is not. Like one dozen has 12 units similarly mole number has 6.022 ×10^23 units. That's it . I wish I could have 1 mole of money . Anyways . This mole no is not as simple as that . It was actually given by a renowned scientist Avogadro on whose name it is named . It stands for the number of atoms present in 1 mole of any substance . Like if I say I have 1 mole of iron , can you tell how many atoms are there in it ? Answer would be 1 mile iron would have 6.022×10^23 atoms of iron . So that's your superhero , The Mole Number .
Now coming to numericals. The very basics are how many moles are there in 25 grams of Hydrogen gas. So you have to learn molar masses of few elements . For hydrogen it is , 1gm/mol . It says 1 gram per mole. 1 mole of hydrogen gas weighs 1 gram . So calculating for moles in 25 gram H2 , we divide available mass by molar mass I.e. 25/1=25 . Therefore 25 grams of hydrogen gas would have 25 moles oh H2 . Similarly you can do for other elements as well !
Secondly if you have been give no of atoms present in an element the divide it by Avogadro's constant I.e. 6.022×10^23 . Also , there's a law which says any 1 mole of gas occupies volume of 22.4 L . So dividing given volume by 22.4 also gives no of moles . I'm summarising it below
No of moles =given mass /molar mass = given no of atoms / Na (no. Of avogadro ) = given volume /22.4 .
Also there is this concept for calculating mass of the element if moles are given . So using same formula ~ moles = mass/molar mass. You know molar mass , no of moles. You can easily find out the mass present . I hope it's clear to you