C1

Question 1

What is a group ?

Answer 1

• column of elements on periodic table
• indicates the number of valence electrons an atom of an element in that group has

Question 2

What is a period ?

Answer 2

• row of elements on periodic table
• indicates the number of energy levels an element in that period has

Question 3

Balance the equation: Fe2O3 + CO –> Fe + CO2

Answer 3

Fe2O3 + 3CO -> 2Fe + 3CO2

Question 4

What is the law of conservation of mass ?

Answer 4

Mass can neither be created nor destroyed

Question 5

Name 3 differences between mixtures and compounds.

Answer 5

• 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

Question 6

Describe a method for making dry crystals of copper chloride salt with evaporation/crystallisation method.

Answer 6

• 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

Question 7

Describe the history of atomic theories.

Answer 7

Dalton (atomic weight) -> JJ Thompson (plum pudding, electrons) -> Rutherford (nuclear model, protons) -> Bohr (energy levels) -> Chadwick (neutrons)

Question 8

Describe JJ Thompson’s plum pudding model.

Answer 8

A ball of positive charge with electrons embedded.

Question 9

Balance: C4H10 + O2 -> CO2 + H2O

Answer 9

figure out