1
Q
What is a group ?
A
- column of elements on periodic table
- indicates the number of valence electrons an atom of an element in that group has
2
Q
What is a period ?
A
- row of elements on periodic table
- indicates the number of energy levels an element in that period has
3
Q
Balance the equation: Fe2O3 + CO –> Fe + CO2
A
Fe2O3 + 3CO -> 2Fe + 3CO2
4
Q
What is the law of conservation of mass ?
A
Mass can neither be created nor destroyed
5
Q
Name 3 differences between mixtures and compounds.
A
- Mixtures:
o no fixed composition
o not chemically bonded
o separated using physical methods - Compounds:
o fixed composition
o chemically bonded
o separated with chemical methods
6
Q
Describe a method for making dry crystals of copper chloride salt with evaporation/crystallisation method.
A
- in a beaker, pour hydrochloric acid
- add solid copper oxide with a spatula and stir with glass rod until fully dissolved
- repeat process until no more copper oxide dissolves in the acid
- in a conical flask with a filter and filter paper, slowly pour the solution through the filter
- discard the excess copper oxide left in the filter paper
- set up a bunsen burner under a tripod with gauze and an evaporating dish
- pour the solution into the evaporating dish then place on the gauze
- light the bunsen burner and heat solution until crystals begin to form at the edges
- cut the heat - do not touch immediately as it is hot
- allow to continue evaporating off water until fully crystallised overnight
7
Q
Describe the history of atomic theories.
A
Dalton (atomic weight) -> JJ Thompson (plum pudding, electrons) -> Rutherford (nuclear model, protons) -> Bohr (energy levels) -> Chadwick (neutrons)
8
Q
Describe JJ Thompson’s plum pudding model.
A
A ball of positive charge with electrons embedded.
9
Q
Balance: C4H10 + O2 -> CO2 + H2O
A
2(C4H10) + 13(O2) -> 8(CO2) + 10(H2O)
