Extra questions - C5
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What is the meaning of the term precipitation reaction
insoluble solid being formed
How can magnesium hydroxide be separated from calcium chloride solution
filtration
Method that can be used to change calcium chloride solution into solid calcium chloride
crystallisation
Complete equation Ca -> Ca 2+ +
2e-
Why can the formation of calcium ions from calcium atoms be described as oxidation
electrons are lost
The reaction between sodium and titanium chloride is a redox reaction. Write a half equation to show that sodium is oxidised in this reaction
Na -> Na+ + e-
Describe how sodium metal conducts electricity
delocalised electrons carry electrical charge through metal
Explain how sodium chloride can conduct electricity
When molten because ions are free to move.
Plan an investigation to find the order of reactivity of three metals Use temp change when each metal reacts with hydrochloric acid
• measure volume of h acid • measure initial temperature with thermometer of h acid • add 3g of each metal • stir • measure highest temp reached of solution after 2 minutes • repeat for each metal • use results to arrange metals in order of reactivity - most reactive metal has largest temperature change
Tungsten is a metal. It is extracted from tungsten oxide. Evaluate the following three methods for extracting tungsten from tungsten oxide:
Carbon - tungsten needs to be separated from tungsten carbide - some tungsten is lost as tungsten carbide - the co2 produced will escape Hydrogen - the water vapour will escape - no separation of solids is needed Iron - tungsten needs to be separated from iron oxide - conclusion: hydrogen is best
What is the equation for the reaction of potassium with water
2K + 2H2O —> 2KOH + H2
How should the solution be heated to produce a salt
Using a boiling water bath
Write an ionic equation for neutralisation
H+ + OH- —> H2O
When making crystals, why is the acid heated
To make sure all the acid has reacted
Calcium reacts with fluorine to produce calcium fluoride (CaF2). Explain how oxidation and reduction have taken place in this reaction. Write about electron transfer in your answer.
• calcium loses two electrons and is oxidised to Ca2+ ion • fluorine gain one electron and is reduced to F− ion and a negative ion produced • reduction is gain of electrons • oxidation is loss of electrons
Describe a test to show that carbon dioxide is produced in this reaction.
limewater turns cloudy
Explain which species is reduced in the reaction between magnesium and iron chloride. 3 Mg + 2 FeCl3 ⟶ 2 Fe + 3 MgCl2 Your answer should include the half equation for the reduction.)
Fe3+ reduction is gain of electrons Fe3+ + 3e(−) ⟶ Fe
name the salt produced if sodium carbonate reacts with dilute nitric acid
sodium nitrate