Topic 6 - Reactivity of metals and equilibrium (Year 10) Flashcards
Which two non-metals are often included in the reactivity series?
Carbon and hydrogen
Potassium is at the top of the reactivity series. Explain why.
It is one of the more reactive metals
Gold is at the bottom of the reactivity series. Explain why.
It is one of the least reactive metals
Calcium is less resistant to oxidation than zinc. What does this tell you about the relative positions of calcium and zin in the reactivity series?
Calcium is higher in the reactivity series than zinc
What would you expect to see when you react an alkali metal with water?
Bubbling/fizzing, metal floating and moving, the metal turning into a ball. (lilac flame - potassium only)
What colour would universal indicator turn the water where an alkali metal has reacted?
Purple - Alkali due to the metal hydroxide being made.
What are the products of the reaction between a metal ad water?
metal hydroxide and hydrogen
How do you test for hydrogen?
Get a light splint and place it into a test-tube of hydrogen gas. It will burn with a squeeky pop. (Squeeky pop test)
Do potassium , sodium and calcium react with water?
Yes, very easily
Do magnesium, lithium, zinc and iron react with water?
Yes, but very slowly, if at all. They all react with steam to produce a metal oxide and hydrogen.
Do copper, silver and gold react with water?
No, these metals are unreactive and don’t react with water or steam
In terms of electrons, What is meant by oxidation?
Loss or electrons
In terms of electrons, What is meant by reduction?
Gain of electrons
In terms of oxygen, what is meant by oxidation?
Gaining of oxygen
In terms of oxygen, what is meant by reduction?
Loss of oxygen
What are the prodcuts of a reaction between a metal and an acid?
Salt and hydrogen
Do potassium and sodium react with acid?
Yes, violently.
Do copper, silver and gold react with acid?
No, they are unreactive
Define: Displacement reaction
When a more reactive element (metal or halogen) takes the place of a least reactive element
What sort of reaction occurs when zinc is added to a solution of copper chloride?
Displacement reaction
What are the prodcuts of the reaction that occurs when zinc is added to a solution of copper chloride?
Zinc chloride and copper
What are the products of a displacement reaction between magnesium and zinc sulfate?
Magnesium sulfate and zinc
Why will a reaction not occur between magnesium sulfate and zinc?
zinc is less reactive than magnesium
What would you see if you placed an iron nail into copper sulfate solution?
Copper is displaced from the blue copper sulfate solution. Red/Orange solid appears on the nail and the solution changes from a blue colour to colourless.
what does a half equation show us?
Half equations show what happens to an element in terms of electrons
Is the following equations oxidation or reduction:
Mg2+ + 2e- → Mg
Reduction
Is the following equations oxidation or reduction:
Cu → Cu2+ + 2e-
Oxidation
Is the following equations oxidation or reduction:
K+ + e- → K
Reduction
Is the following equations oxidation or reduction:
Na → Na+ + e-
Oxidation
How can you remember whether oxidation or reduction is loss or gaining of electrons?
OIL RIG (oxidation is loss, reduction is gain)
True or False: A metal ore is any rock which contains a metal compound?
False, A metal ore is a rock which contains enough metal to make it economically worthwhile extracting the metal from it.
Define: Native metal
A metal which is found in its natural state e.g. gold
What are the two way of extracting a metal from its ore
displacement with carbon or extracting metals
Where would you find native metals on the reactivity series?
At the bottom, native metals are extrememly unreactive.
For metals above carbon, how do you extract them from their ore?
Electrolysis
For metal ores below carbon, how do you extract the metal?
Displacement reaction with carbon
How is iron extracted from its ore?
Iron is extracted by reduction/displacement with carbon. This is because carbon is more reactive than iron.
Why is gold found as uncombined elements in the earth’s crust?
It is unreactive so doesn’t combine to form compounds
Copper can be extracted from copper oxide (black poweder) by reducing it with carbon. What is the other product in this reaction?
Copper and carbon dioxide
Explain why some metals are extracted with electrolysis rather than by reductionwith carbon?
Metals more reactive than carbon cannot be extracted by reduction with carbon. Instead have to be extracted by electrolysis.
How is aluminium extracted from it’s ore?
Electrolysis
At which electrode is aluminium formed during the electrolysis of aluminium ore?
Cathode
Explain why the extraction of aluminium from aluminium oxide is done by electrolysis
Aluminium is more reactive than carbon
Explain why the extraction of aluminium is more expensive than the extraction of copper using carbon
Aluminium is above carbon which means it must be extracted by electrolysis. Electrolytsis is more expensive than reduction with carbon due to the energy needed to melt the aluminium ore and electrolyse it. Reduction is less expensive the carbon needed is cheap.
Explain what happens in the electrolysis of aluminium oxide
aluminium oxide is heated to high temperatures before being electrolysed.
Name two biological methods used to extract metals
Phytoextraction and bioleaching
What is phytoextraction?
Growing plants that absorb metal compounds. The plants are then burnt to form ash, then the metal extracted.
What is bioleaching?
Use of bacteria on low grade ore. The bacteria produce a solution containing the metal ions (leachate). The metal is then extracted by displacement , then purified by electrolysis.
What is the disadvantage of phytoextraction and bioleaching?
They are slow processes
Why might scientist want to further investigate biological methods of extracting metals from low grade ores.
supply of high grade ores are limited, methods of extraction from low grades will be needed and the environmental impacts from biological methods is less than mining.
What are are the advantages of using biological methods of extraction?
No harmful gases are prdouced (from mining the ore). Less damaged to landscape than mining. Conserves supplies of higher grade ores. Bioleaching does not require high temperatures. Phytoexctraction can extract metals from contaminated soils.
Define recycling
the process of converting waste products into new materials.
True or Flase: Recycling is damaging to the economy
False, Recycling is generally beneficial to the environment.
What is meant by a finite material?
The is only a small amount of the material.
Define non-renewable
The material will eventually run out.
What are the advantages of recycling?
Natural reserves of metal ores will last longer. Mining ores damages landscapes - less mining needed for recyling. Less pollution from the mining stages. Need less energy to recycle. Less waste material ends up in landfil sites.
What is a Life Cycle Assessment(LCA)?
An assessment of the environmental impact of a product over the course of its life
What are the 4 stages in an LCAs?
Raw Material, Manufacturing, Product Use and Disposal
Suggest two factors that should be considered when assing the manufacturing stage in the LCA of a product?
The energy input to make the product, the use of resources, the potential for air pollution and production of harmful fumes, the disposal of water and waste products and whether any waste products can be turned into other useful chamicals.
What is a revisible reaction?
A reversible reaction is a reactio that can go both ways. Reactants can react together to form products and the products can react together to give you back the reactats.
How do you show a reversible reaction in an equation?
The double arrow
Define equilibrium
the concentrations of reactants and products do not change. But the forward and reverse reactions have not stopped - they are still going on, and at the same rate as each other.
What is a closed system?
A system where no reactants or products can escape or be added.
Why does the cocentration of a product remain the same at equilibrium?
At equilibrium, the forward and backward reactions occur at the same rate. The amount of any product remains the same, as it is produced as quickly as it is used up.
What is the Haber process?
The haber process is the manufacturing process for ammonia (a key chemical needed to make fertilisers).
What are the conditions for the Haber Process?
Temperature - around 450 degrees celcius, Pressure - around 200 atmospheres, Iron catalyst.
Why is is a catalyst added into the haber process?
Speed up the rate of reaction by lowering the activation energy.
Hydrated copper sulfate can take part in reversible reaction to form anhydrous copper sulfate and water. How would you go from hydrated to anhydrous copper sulfate, and what would you see?
Heat up the hydrated copper sulfate. It will turn from a blue colour to a white colour.
What is Le Chatelier’s principle?
If a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract/oppose the change.
What are the 3 ways of affecting the position of equilibrium?
Pressure, temperature and concentration
True or False: Increasing the temperature of a reversible reaction moves the equilibrium in the endothermic direction?
True, the equilibrium moves in the endothermic direction to try and decrease the temperature
True or False: increasing the concentration of a reactant moves the position of equilibrium towards the reactant side?
False, equilibrium moves towards the products to try and decrease the concentration.
True or False: Increasing the pressure moves equilibrium in the direction where there are fewer moles of gaseous molecules?
True, increasing pressure forces equilibrium in the direction where there are fewer gaseous molecules
If a reversible reaction is endothermic in the forward directio, what can you predict about the backward reaction?
The backward reaction will be exothermic.
How does the reactivity of a metal affect the temp in displacement
More reactive the metal, the more heat released
Define : Oxidation involving oxygen
When a substance gains oxygen
Define : Reduction involving oxygen
When a substance loses oxygen
How does a metals reactivity affect its ease of extraction
The more reactive, the harder to extract
How do you extract metals below carbon in the reactivity series
Reduction with carbon
How do you extract metals above carbon in the reactivity series?
Electrolysis
What’s attracted to cathodes and what charge?
Cations (positive)
What’s attracted to anodes and what charge?
Anions (negative)
What happens when the cations reach the cathode?
They are reduced (gain electrons) and discharged.
When anions move to the anode, what do they do?
They are oxidised (lose electrons) and so are discharged
What happens at the anode in electrolysis of aqueous solutions?
If a halide is present, the halide is produced. If there’s no halide present, oxygen and water is produced.
