paper 2

Question 1

Concentration = (of a solution)

Answer 1

moles (mol) / volume of solution (dm^3)

Question 2

Number of Moles = (in a solution)

Answer 2

concentration (mol/dm^3) x volume (dm^3)

Question 3

Volume = (in a solution)

Answer 3

Moles (mol) / Concentration (mol/dm^3)

Question 4

Grams per dm^3 =

Answer 4

Mass of chemical (g) / volume of solvent (dm^3)

Question 5

Avagrado’s Law =

Answer 5

One mole of gas occupies 24 dm^3

Question 6

Convert the moles of any gas at RTP to a volume:

Answer 6

Volume (dm^3) = Moles of gas x 24

Question 7

Calculating volumes in reactions with known masses:

Answer 7

1) Calculate the moles of the known substance.
2) Find the moles of gas using the balanced equation.
3) Convert the moles into a volume using vol = mol x 24

Question 8

Define Electrolysis:

Answer 8

Breaking down of a substance using electricity

Question 9

What is Oxidation and Reduction?

Answer 9

Oxidation is the loss of electrons

Reduction is the gain of electrons

Question 10

What is a cation?

Answer 10

positive ions in the electrolyte

Question 11

What is a cathode?

Answer 11

The negative electrode

Question 12

What is the anode?

Answer 12

The positive electrode

Question 13

How does electrolysis occur?

Answer 13

An electric current is passed through an electrolyte (molten or dissolved ionic compound), causing it to decompose.

Question 14

Why can molten ionic compounds be electrolylsed?

Answer 14

The ions can move freely

Question 15

What is an ionic half equation?

Answer 15

They show what is happening at each electrode, (splits the equation up so it is easier to understand).

Question 16

What is attracted to the cathode?

Answer 16

The Positive (+ve) ions are attracted to the cathode (-ve)

Question 17

What is attracted to the anode?

Answer 17

The Negative (-ve) ions are attracted to the anode (+ve).

Question 18

What are the electrodes made from?

Answer 18

Inert material so they don’t take part in the reaction.

Question 19

What is an electrochemical cell, and what components are in them?

Answer 19

A circuit made from an anode, cathode, electrolyte, power source and wires connecting the electrodes.

Question 20

Which inert elements are usually used in the electrodes?

Answer 20

Graphite or Platinum

Question 21

Why are aqueous solutions harder to electrolyse?

Answer 21

Aqueous solutions contain all the ions from the ionic compound as well as Hydrogen and Hydroxide ions from the water.

Question 22

What is the charge on ions

Hydrogen and Hydroxide

Answer 22

Hydrogen = H+
Hydroxide = OH-

Question 23

At the cathode in an Aqueous solution, what happens if Hydrogen & Metal Ions are present?

Answer 23

If hydrogen is more reactive than the Metal then Hydrogen gas is produced.
If the Metal ion is more reactive than Hydrogen then a solid pure metal layer is produced.

Question 24

At the anode in an Aqueous solution, what happens is Hydroxide and Halide Ions are present?

Answer 24

Molecules of Chlorine, Bromine or Iodine will be formed.

Question 25

How many electrons are present in the outer shell of group 1 elements.

Answer 25

1 outer shell electron

Question 26

Why do atoms become more reactive as you move down the group? (in group 1)

Answer 26

The outer shell electron is further from the nucleus, meaning there is less attraction between them. The outer shell electron is more easily lost and they become more reactive.

Question 27

How many atoms does a Halogen need to gain to form a stable outer shell?

Answer 27

Needs to gain an electron and form a 1 - atom.

Question 28

Does reactivity decrease or increase for Halogens as they go down the group.

Answer 28

Reactivity decreases as the outer shell is further away from the nucleus so the attraction is weaker.

Question 29

What are reaction profiles?

Answer 29

Diagrams that show the relative energies of the reactants and products in a reaction, and how energy changes in the course of a reaction.

Question 30

In an reaction profile for an endothermic reaction, which has more energy, the products or reactants?

Answer 30

The products, as the energy is taken in during the reaction

Question 31

In an reaction profile for an exothermic reaction, which has more energy, the products or reactants?

Answer 31

The reactants, as energy is given out during the reaction