C5 Flashcards
How can you extract a metal from it’s oxide?
The metal oxide must be Reduced
What is the whole reactivity series?
Pottasium, sodium, calcium, magnesium, aluminium, (carbon), zinc , iron, tin, lead, (hydrogen), copper, silver, gold, platinum
What is the reactivity series poem?
Pegy Sue Loves Cooking Meat At Zoos In Tropical London Causing Severe Gut Pain
What is reactivity series based on?
It is determined on how easily they loose electrons - forming positive ions
What happens when you react a metal with water? And give an example
Metal + water —-> Salt + Hydrogen
Ca + 2H20 —–> Ca(OH)2 + H2
What happens when you add a Metal and Acid?
Acid + metal —-> Salt + Hydrogen
The more reactive the metal the faster the reaction will go
What is the definition of a displacment reaction?
A more reactive metal will displace a less reactive metal from an aqueous solution from one of it’s salts
Give an example of a displacment reaction?
Mg + CuSO4 —-> MgSO4 + Cu
What is an ionic equation?
An ionic equation shows only the atoms and ions that change in a reaction.
What is a spectator ion?
An ion that stays the same in a reaction so therefore they are not shown in the ionic equation
Give an example of a ionic equation ( Mg + Cu 2+ ) without state symbols. And explain what’s happening. Show the half equation aswel.
Mg + Cu 2+ —-> Mg 2+ + Cu
The Mg gets oxidised ( looses 2 electrons ) becoming a positive ion and the Cu 2+ become without charge as it gains the 2 electrons that Mg lost
Mg —> Mg 2+ + 2e- Cu 2+ + 2e- —> Cu Half equations
What is oxidation and reduction? Also include the in terms of electrons?
Oxidation is the gain of oxygen, reduction is the loss of oxygen
Oxidation is the loss of electrons, reduction is the gain of electrons
What is a metal ore?
It is a rock containing metal that has enough metal to make it worth extracting the metal
Some metals can be extracted from their ores chemically by reduction using ……
Carbon
Show the reduction reaction of iron(111) oxide + carbon
2Fe203 + 3C —-> 4Fe + 3CO2
Which metals can be extacted by reduction using carbon?
Metals below carbon in the reactivity series can be extracted by reduction using carbon.
This is because Carbon can only take away the oxygen from materials which are less reactive than carbon itself
Which metals are extracted by electrolisis?
Metals higher than carbon in the reactivity series have to be extacted using electrolisis which is expensive.
What 2 things neutralise each other?
Acid + base
What is the general equation for a neutralisation reaction?
Acid + base —> salt + water
How can you make a copper salt? (The crystal practical)
You can make copper sulfate crystals from copper (||) oxide ( an insoluble base ) and sulfuric acid
The equation for this reaction is:
H2SO4 + CuO —-> CuSO4 + H2O
1) Add insoluble copper oxide to sulfuric acid and stir. Warm gently on a tripod
2) The solution turns blue as the reaction occurs, showing that copper sulfate is being formed. Excess black copper oxide can be seen
3) When the reaction is complete, filter the solution to remove excess copper oxide.
4) You can evaporate the water so that crystals of copper sulfate start to form. Stop heating when
you see the first crystals appear at the edge of the solution. Then leave for the rest of the water to evaporate off slowly. This will give you larger crystals.
Acid + alakali
Acid + alakali —-> salt + water
What happens when you react acid with a carbonate and give an example?
Acid + carbonate —-> Salt + water + carbon dioxide
2HCL + Na2CO3 —-> 2NaCl + H2O + CO2
What is a base?
Bases, which include alkalis, are substances that can neutralise acids. Metal oxides and metal hydroxides are bases. Examples include iron oxide and copper hydroxide, which are both insoluble in water.
What is a alkali?
Soluble hydroxides are called alkalis. Their solutions are alkaline.
An example is sodium hydroxide solution.
What is neutral ( neither acidic nor alkali ) ?
Water
The lower the pH of a solution, the more …… it is
Acidic
The higher the pH of a solution, the more ….. it is
Alkaline
How can you measure the pH of a solution?
An indicator is a dye that changes colour depending whether it’s above or below a certain pH and some indicators contain a mixture of dyes that means they gradually change colour over a broad range of pH.
A pH probe attached to a pH meter can also be used to measure pH electronically. The probe is placed in the solution you are measuring and the pH is given on a digital display as a numerical value, meaning that it’s more accurate than a indicator
What is pH a measure of of ?
pH is a measure of the concentration of Hydrogen Ions in the solution ( H+ )
What do acids produce in water? Give examples
Acids produce Protons in water - they ionise in a aqueous solution
For e.g. HCL —-> H+ + NO3-
What’s the difference between a strong acid and a weak acid? Give examples for each one
Strong acids (e.g. sulfuric, hydrochloric and nitric acids) ionise completely in water. All acid particles dissociate to release H+ ions.
Weak acids (e.g. ethanoic, citric and carbonic acids) do not fully ionise in solution. Only a small proportion of acid particles dissociate to release H+ ions.
Stong acid : HCL —->H+ + Cl-
Weak acid : CH3COOH —–> H+ + CH3COO-
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What is more reactive - a strong acid or a weak acid ?
Reactions of acids involve the H+ ions reacting withother substances. If the concentration of H+ ions is higher, the rate of reaction will be faster, so strong acids will be more reactive than weak acids of the same concentration.
On the pH scale what tells you the concentration of H+ ions in each pH?
For every decrease of 1 on the pH scale, the concentration of H+ ions increases by a factor of 10.
So, an acid that has a pH of 4 has I0 times the concentration of H+ ions of an acid that has a pH of 5. For a decrease of 2 on the pH scale, the concentration of H+ ions increases by a factor of 100.
The general rule for this is:
What’s the difference between a strong acid and a concentrated acid?
Acid strength (i.e. strong or weak) tells you what proportion of the acid molecules ionise in water.
The concentration of an acid is different. Concentration measures how much acid there is in a certain volume of water. Concentration is basically how watered down your acid is.
