Chemistry Doubt

[Dhruv Pau]

Chemistry problem.......
What is a mole and there is something that there is a certian amount of atoms in a mole no matter which element is it and how much space does 1 mole of any gas occupy??

 

[smart_boy]

Chemistry problem.......
What is a mole and there is something that there is a certian amount of atoms in a mole no matter which element is it and how much space does 1 mole of any gas occupy??

What u wanna know is not very small thing to understand. You know that different elements have atoms with different atomic masses, as nucleon numbers are different. Therefore, 10 atoms of iron (just for example) will not weigh the same as 10 atoms of any other element like copper. But each atom of iron will weigh the same as any other atom of iron ONLY.
Therefore, it was found out that if any element's 6.022 X 10 raised to 23 atoms were taken, the total mass of all would be the atomic mass of one atom, but in grams.
This means, for example, if you take 6.022 X 10 raised to 23 atoms of sodium, the total mass will be equal to 23 Grams (as 23 is the atomic mass of sodium in the periodic table)
So one mole of any substance is the same thing - the atomic mass of an element expressed in grams. And one mole of ANY element will have 6.022 X 10 raised to 23 atoms..!!! This number is called Avogadro's constant (as it is named after the scientist Avogardro).
More examples are - one mole of carbon would be 12 grams, one mole of magnesium would be 24g and so on. In case of hydrogen gas, 1 mole will be 2 grams and not 1 gram because the element exists as a molecule H2. Same applies for oxygen, chlorine, bromine and many others.
This applies for compounds also. If you calculate the total mass of nuclei in a water molecule (H2O) it will be 18. So one mole of water would be 18grams!! and in this case, the number of MOLECULES (not atoms) would be equal to Avogadro's constant.
This person, Avogadro, also found out that 24 litres of any gas at room temp and pressure will have one mole of atoms (or molecules in it). So 24 liters, which is same as 24 cubic decimetre (dm3), is known as the gas constant. So 24dm3 of, for example argon, will be 1 mole of argon, 12dm3 would be 0.5 mole, and so on.
If you still dont understand, please go to xtremepapers chemistry revision... as i m tired of typing so much..!!!!

 

[Dhruv Pau]

Thank You Soo much!

 

[smart_boy]

Thank You Soo much!

Ur welcome

 

[Iishrak]

Hello, I'm here with some questions, that will be really helpful if u people can solve it, with explanation .
Q1. In term of structure, explain why the melting point of MgO is higher than that of MgO
View attachment 20398

 

[Iishrak]

 

[examkiller]

Hey guys, Im having trouble with moles, especially the pastpaper questions. They seem hard, Any tips.
I did some questions on moles and can you please show me how solve step by step. What to do and what not to do.
question is they want the mole :
1) 50.9 of CuSO4.5H20
2) 9.64g of (NH4)2S04.Fe2(So4)3.24H20 ?
What to do to when brackets and dots etc .. thanks !!
And also any tips to better understand Stoichiometry ?

 

[Iishrak]

Hey guys, Im having trouble with moles, especially the pastpaper questions. They seem hard, Any tips.
I did some questions on moles and can you please show me how solve step by step. What to do and what not to do.
question is they want the mole :
1) 50.9 of CuSO4.5H20
2) 9.64g of (NH4)2S04.Fe2(So4)3.24H20 ?
What to do to when brackets and dots etc .. thanks !!
And also any tips to better understand Stoichiometry ?

chk out khanacademy's video on stoichiometry