Quantitative Chemistry Flashcards
Relative atomic mass
- The average mass of all the isotopes of that element
What is the symbol for relative atomic mass?
Ar
What is the symbol for relative formula mass?
Mr
% mass of an element =
no. of atoms of an element x Ar of element
___________________________ x100
total mass of compound
What is the formula that links mass, moles, and Mr?
mass = moles x Mr
1 mole of any substance:
6.02 x 10²³ particles
What does the law of conservation of mass state?
No atoms are lost or made during a chemical reaction
What is a chemical change?
A rearrangement of the atoms in the reactants, to form the products
In a chemical reaction, is there any change in the overall mass of the substances?
No
Why is it more difficult to measure the mass of a gas than the mass of a liquid or solid?
A gas can easily escape into the air
What does it mean for a reactant to be a ‘limiting reactant’?
It all reacts and limits how much product can be formed
What does it mean for a reactant to be ‘in excess’?
It does not all react, and has no affect on the amount of product formed
