Quantative Chemistry

Question 1

What is the law of conservation of mass?

Answer 1

The law of conservation of mass states that no atoms are lost or made
during a chemical reaction so the mass of the products equals the mass
of the reactants.

Question 2

Define relative atomic mass and relative formula
mass.

Answer 2

RAM - average mass of atoms in an element taking into account masses
and abundance of its isotopes, relative to 12C.
RFM - sum of RAM’s of all atoms in the formula.

Question 3

What is Avogadro’s constant?

Answer 3

The number of atoms, molecules or ions in a mole of a given substance.
The value of the constant is 6.02 x 10^23

Question 4

What is the formula that links mass, molecular mass and moles
together

Answer 4

Mass = Mr x Moles

Question 5

State what we mean by a limiting reactant in a chemical reaction

Answer 5

In a chemical reaction involving two reactants, it is common to use an
excess of one of the reactants to ensure that all of the other reactant is
used. The reactant that is completely used up is called the limiting
reactant because it limits the amount of products.

Question 6

Write down the two formulae that link concentration, mole/mass
and volume together

Answer 6

Concentration (g per dm3
) = Mass (g)/Volume (dm3
)
Concentration (mol per dm3
) = nr of moles/volume (dm3
)