Definitions: Amount of Substance

Question 1

Define Ar

Answer 1

The relative atomic mass (Ar), is the weighted average mass of an atom of an element,

taking into account its naturally occurring isotopes,

relative to the relative atomic 1/12th mass of an atom of carbon-12.

Question 2

Define Mr

Answer 2

The relative molecular mass, Mr, of a molecule is the mass of that molecule

compared to 1/12 the relative atomic mass of an atom of carbon-12.

Question 3

Define Avogadro Constant

Answer 3

The Avogadro constant or Avogadro number is the number of atoms in 12g of carbon-12.

Question 4

What is the ideal gas equation?

Answer 4

pV = nRT

Question 5

What is the EMPIRICAL formula?

Answer 5

the formula that represents the simplest whole number ratio of the atoms of each element present in a compound.

Eg, the empirical formula of CO2, for every carbon atom there are two oxygen atoms.

Question 6

Define Concentration

Answer 6

The concentration of a solution tells us how much solute is present in
a known volume of solution.

Question 7

What is the mole?

Answer 7

The amount of substance that contains 6.022 x 1023 particles is called a mole.

Question 8

What is stoichiometry?

Answer 8

The ratio in which the reactants react and the products are produced, in simple whole numbers, is called the stoichiometry of the reaction.