QUANTATIVE CHEMISTRY

Question 1

Formula for mass, number of moles and formula mass

Answer 1

mass=Mr x mole

Mr= Mass/mole

Question 2

Balancing equations steps

Answer 2

MASS( in grams usually)
Mr
Moles
Ratio (from balanced equation)

Question 3

Law of conservation of mass

Answer 3

the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction.

Question 4

Percentage yield equation

Answer 4

percentage yield = actual yield/
theoretical yield x 100

Question 5

why do so few reactions have 100% yield?

Answer 5

-some of the products may be lost when sperated from the mixture
-Some of the reactants may react to give an unexcpected products
-the reaction may be reverisble.

Question 6

atom economy formula

Answer 6

mass of useful prod. / mass of all prod.
x 100

Question 7

Gas volume equation

Answer 7

number of moles= volume of gas/
24

Question 8

why is atom economy important in industry?

Answer 8

-helps find ways to make production more efficient: speed up reactions
- helps minimise waste and maximise profit

Question 9

What is a limiting reactant?

Answer 9

the reactant that gets consumed first in a chemical reaction and therefore limits how much product can be formed

the left over atom is IN EXCESS