Stoichiometry theory Flashcards
What is relative atomic mass (Ar)
It is the average mass of an atom of an element relative to the 1/12th of mass of an atom of c-12 isotope
Formula for relative atomic mass
Mean mass of an element÷ 1/12th of the mass of an atom of C12
What is relative molecular mass (Mr)
It is the average mass of a molecule relative to the 1/12th of mass of an atom of C-12 isotope
How can relative molecular mass be calculated?
By adding relative atomic mass values of atoms in the molecule
What is relative formula mass?
Similar to relative molecular mass.
When molecules are associated with water of crystallization the term formula mass comes into play
What is molar mass?
Molar mass is the mass per mole (mass of 1 mole) of any substance
What is the unit for molar mass ?
Grams/Mol
What is the formula to calculate number of moles
n=m/M
n= no of moles
m= mass of substances
M= Molar mass of substance
Unit Is mol
What is avogadros constant?
It is the number of particles in one mole of a substance
What is the numerical value of avogadros constant?
6.02×10^23
How are moles and avogadros constant related?
1 mol= 6.02×10^23
What is a mole?
Mole is the amount of substance which contain the same number of particles as the number of atoms which are exactly there in 12g of C-12 isotope
Why do we need to balance chemical equations?
*They tell us how much of each substance is involved in a chemical reaction and how much product is made
- if we have too much of a reacting it will be wasted
*if we have too little of a reactant not all of the other reactant will react
- provides the molar ratios between the reactants and products
How to calculate the formula of a compound?
- the formula of a compound can be deduced using the masses of the reactants
- follow the law of conservation of mass
What is conservation of mass principle?
The total mass of a chemical reactions reactants is equal to the total mass of the product