Chapter 3

Question 1

Mole definition

Answer 1

The amount of substance that contains 6.02 x 10^23 particles

Question 2

Avogadro constant

Answer 2

The number of particles in each mole of carbon -12

Question 3

Molar mass

Answer 3

The mass per mole of a substance

G mol -1

Question 4

Molecular formulae

Answer 4

The number of atoms of each element in a molecule

Question 5

Empirical formula

Answer 5

The simplest whole ratio of atoms of each element in a compound

Question 6

Relative molecular mass

Answer 6

Compares the mass of a molecule with the mass of an atom of carbon 12

Question 7

Relative formula mass

Answer 7

Compares thé mass of a formula unit with the mass of an atom of carbon 12 - substances that don’t exist as molecules

Question 8

Hydrated =

Answer 8

Water molecules are part of their crystalline structure

Question 9

When heated bonds between water are broken Leaving white anhydrous copper (II) sulfate

Method:

Answer 9

Weigh empty crucible
Weigh c + hydrated salt
Heat c
Weigh c + anhydrous salt

Question 10

Standard solution

Answer 10

Solution of known concentration

Question 11

Stoichiometry

Answer 11

The balancing numbers that give the ratio of the amount of each substance

Question 12

Theoretical yield

Answer 12

The maximum mass of a product that could be formed in a reaction

Question 13

Percentage yield

Answer 13

Shows the conversion of starting materials into desired product

Question 14

Factors that may affect percentage yield

Answer 14

• reactants may react in a different way then expected
• reaction may not go to completion
• may lose product

Question 15

Limiting reagent

Answer 15

The reactant that is not in excess will be used up first and stop the reaction

Question 16

Atom economy

Answer 16

A measure of how many atoms in the reactants form a desired product

Atoms with higher atom economies produce fewer waste

Question 17

Molar gas volume

Answer 17

Volume per mole of gas molecules at stated temperature and pressure

Question 18

Assumptions for ideal gas

Answer 18

Random motion
No intermolecular forces
Negligible size
Elastic collisions

Question 19

Finding the relative molecular mass of a volatile liquid

Answer 19

Add sample of volatile liquid to a small syringe via needle 
Inject the sample into a gas syringe 
Rewrite the gas syringe 
Place gas syringe in boiling water bath 
Liquid vaporises producing a gas 
Record the pressure of the gas