quiz 4[redox n thermo]
DESCRIPTION
chemistry revision SPMTRANSCRIPT
QUIZ 4 (REDOX AND THERMOCHEMISTRY)1. Definition of redox reaction:
OXIDATION REDUCTION1. Loss or gain of oxygen A substance gain oxygen [1]2. Loss or gain of hydrogen [1] A substance gains hydrogen3. Transfer of electrons A substances loses electrons [1]4. Change in oxidation number Increase in oxidation number [1]
2. Complete the table into:
Chemical reaction Substance oxidized
Substance reduced
Oxidizing agent
Reducing agent
i) Mg + CuO MgO + Cuii) H2S + Cl2 S + 2HCliii) 2Na + Cl2 2NaCliv) Mg + CuSO4 MgSO4 + Cu
3. Complete the following table to explain redox reactions in the three test tubes:
Displacement of Metal Change from iron(II) to iron(II) Displacement of Halogen
Experiment
Observation
Oxidizing agentReducing agentReduction half equationExplain reduction in terms of change in oxidation number
4. Redox reaction : Transfer of electron at a distance.Label anode and cathode for the given U-tube below.
Complete the table below by classifying the reagent given into oxidizing/reducing agent and state the observation:
Reagent Oxidizing/ Reducing
Agent Observation Reagent
Oxidizing/ Reducing
AgentObservation
Iron(II) sulphate
Bromine water
Acidified K2Cr2O7
Potassium bromide
Chlorine water
Acidified KMnO4
Potassium iodide
Reactive metal e.g
ZincIron(III)
sulphate
THERMOCHEMISTRY5. Complete the table below:
Heat of Reaction
Definition Thermochemicalequation
Ionic equation Energy level diagram
Heat of Precipitation
Pb(NO3)2 + Na2SO4
PbSO4 + 2NaNO3
∆H=-50.4kJmol-1
Heat of Displacement
Zn + CuSO4 ZnSO4 + Cu
∆H=-217 kJmol-1
Heat of Neutralisation
KOH + HNO3 KNO3 + H2O
∆H=-57kJmol-1
Heat of Combustion
C2H5OH + 3O2 2CO2 + 3O2
∆H=-1366kJmol-1
6. Draw the apparatus set-up to determine the heat of combustion of propanol [2m]
7. The table below shows the molecular formula and the hat of combustion of three types of alcoholAlcohol Molecular Formula Heat of Combustion/ kJmol-1
Methanol CH3OH 725Ethanol C2H5OH 1376
Propan-1-ol C3H7OH 2015
Explain why there are differences in the value of heat of combustion of the alcohols in the table [3m]………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
8. Question from Quiz 1 ….....................................................................................................................................................................................................................................................................................................................................................
9. Question from Quiz 2 ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………...
10. Question from Quiz 3…..………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………