Popular AQA Chemistry Unit 2 Questions and Answers

After doing many papers i composed the popular questions and wrote the answers to them aswell :)

HideShow resource information
Preview of Popular AQA Chemistry Unit 2 Questions and Answers

First 314 words of the document:

Equilibria
Define the term dynamic equilibrium (2)
Where the forward and backward reactions are happening at the same rate therefore
concentrations of all reactants and products remain constant
State Le Chatelier's principle (1)
An equilibrium opposes change
Justify the reason for a comprise in temperature and pressure in the Haber process (2)
Temperature- appropriate balance between rate of reaction and percentage yield
Pressure- appropriate balance between rate of reaction and cost
What is the effect of catalyst in a reversible reaction? (2)
Does not effect yield and increases rate of reaction for both reactions equally
Kinetics
Give the meaning of a catalyst (2)
A substance that increases rate of reaction without itself being chemically altered
Give the main advantage of using a powered catalyst instead of solid block (1)
Increase surface area so more catalyst surface contact
Define the term activation energy (2)
The minimum energy required for a collision to break bonds
Explain the effect an increase in temperature has on the rate of a chemical reaction (3)
Increases as more particles have energy greater than the activation energy resulting in more
successful collisions
Explain the effect an increase in pressure has on the rate of a chemical reaction? (3)
Increases as more particles are closer to together in a given volume resulting in more successful
collisions
Explain the effect an increase in concentration has on the rate of a chemical reaction? (3)
Increases as more particles are dissolved in solution per litre resulting in more successful collisions
Explain the effect of the addition of a catalyst has upon the rate of a chemical reaction? (3)
Increase dues to a lowered activation energy so more particles have energy greater than activation
energy and can also provide an alternate route to the product/s

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Energetics
Define the term standard enthalpy of formation (3)
The enthalpy change when one mole of substance is formed from its constituent elements under
standard conditions, with all reactants and products in their standard states
Define the term stand enthalpy of combustion (3)
The enthalpy change when one mole of substance is completely burnt in oxygen under standard
conditions, with all reactants and products in their standard states
States Hess' Law (1)
The enthalpy change from reactants to products remains the same whatever route is…read more

Page 3

Preview of page 3

Here's a taster:

H2SO4 +6
SO2 +4
Write a half equation for the reduction of Sulphur from H2SO4 to SO2 (1)
H2SO4 + 2H+ + 2e- SO2 + 2H2O
Write a half equation for the oxidation of Bromide ions to Bromine molecules (1)
2Br - Br2 + 2e ­
Construct an overall equation for this reaction (1)
H2SO4 + 2HBr Br2 + SO2 + 2H2O
Write a half equation for the reduction of Sulphur from H2SO4 to H2S (1)
H2SO4 + 8H+ + 8e - H2S + 4H2O…read more

Page 4

Preview of page 4

Here's a taster:

State any solid products produced from the full reaction between NaI and H2SO4 and the
observation of the products (2 or 3)
NaHSO4 (white solid)
Sulphur yellow power
State why an acid may be added to a aqueous solution of a particular halide ion before
reacting with Silver Nitrate (1)
To remove OH- or CO3- impurities
Write an ionic equation for the removal of OH- impurities and CO3- impurities with Nitric acid (2)
H+ + OH- H2O
2H+ + CO3- CO2 + H2O
State the…read more

Page 5

Preview of page 5

Here's a taster:

Write an equation including state symbols of the reaction between Magnesium and water (2)
Mg(s) + 2H2O(l) Mg(OH)2(s) + H2(g)
State a use of Magnesium hydroxide (1)
Used for indigestion problems
Write an equation including state symbols of the reaction between Magnesium and steam (2)
Mg(s) + H2O(g) MgO(s) + H2(g)
State the reagent and write an ionic equation including state symbols of the test for aqueous
Barium Chloride (2)
Reagent:- Na2SO4
BaCl2(aq) + SO4- (aq) BaSO4(s) + 2Cl-(aq)
Extraction of Metals
Name the process…read more

Page 6

Preview of page 6

Here's a taster:

State why recycling Iron is a better alternative to extraction of Iron oxide (1)
Less energy is used
State why Aluminium oxide is dissolved in molten cryolite (1)
Reduces reaction temperature
Write a half equation for the electrolysis of Aluminium oxide at the positive electrode to
produce aluminium (1)
Al3+ + 3e- Al
Write a half equation for the electrolysis of Aluminium oxide at the negative electrode to
produce oxygen (1)
2O2- O2 + 4e-
Give two reasons as to why electrolysis of Aluminium oxide…read more

Page 7

Preview of page 7

Here's a taster:

Advantage:- Less Mg than Na is required
Disadvantage:- MgCl2 has no value/uses
Write an equation for the reduction of Tungsten (VI) by hydrogen (1)
WO3 + 3H2 W + 3H2O
Explain why using Hydrogen is a last resort (1)
Hydrogen is flammable and can cause an explosion
State why Carbon is not used as a reducing agent (1)
A carbide is formed…read more

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »