C5 Flashcards
What is the reactivity series?
The reactivity series is a list of metals in order of their reactivity, with the most reactive metals at the top and the least reactive ones at the bottom.
What is the reactivity series?
PSLC MAC ZINTL H CSG
potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Nickel
Tin
Lead
Hydrogen
Copper
Silver
Gold
How is metals reactivity determined?
By how easily they lose electrons - forming positive ions. Higher up reactivity series, more they easily form positive ions.
What happens when metals react eith water or acid?
The metal loses electrons and form positive ions. Higher metal up is, the more easily it reacts with water or acid.
What is the equation for the reaction between metal + water?
Metal + water ~ metal hydroxide + hydrogen
What is the equation for the reaction of acid + metal?
ACID + METAL ~ salt + hydrogen
Example:
Iron + hydrochloric acid ~ iron(II) chloride + hydrogen
How is the speed of a reaction indicated in the reaction acid + metal?
By the rate at which the bubbles of hydrogen are given off. The more reactive the metal, the faster the reaction will go.
How does magnesium react with dilute acids?
Reacts vigorously and produces loads of bubbles
How does zinc and iron react with acid?
Reacts slowly but more strongly if you heat them up
Reaction with water and reaction with dilute acid for the reactivity series
Insert pic
What is an ore?
An ore is a type of rock that contains metal compounds
What is a displacement reaction?
When a more reactive metal disppaces a less resctive metal
What is oxidation and reduction?
The loss of electrons is oxidation
The gain of electrons is reduction
What does OILRIG stand for?
Oxidation is loss, reduction is gain
What is an ionic equation?
An equation that only shows the atoms and ions that change in a reaction
What will a more reactive metal do to a less reactive metal?
A MORE REACTIVE METAL WILL DISPLACE A LESS REACTIVE METAL FROM ITS COMPOUND
What will happen if you put iron in a solution of copper sulfate?
The more reactive iron will “kick out” the less reactive copper from the solution.
Iron + copper sulfate ~ iron sulfate + copper
Describe these equations: (Fe ~ Fe2+ + 2e- ) and Cu2+ + 2e- ~ Cu
The iron loses 2 electrons to become a 2+ ion - its oxidised.
The copper ion gains 2 electrons becoming a copper atom - its reduced
In displacement reactions, is it always the metal ion that gains electrons and is reduced. And is it the metal atom always loses electrons and is oxidised.
Yes, ALWAYS
Example of an ionic equation and its full equation: Mg + ZnCl2
Ionic equation: Mg + Zn2+ ~ Mg2+ + Zn
Full: Mg + ZnCl2 ~ MgCl2 + Zn
Ionic equations only show the particles that react and the products they form
Practicle for displacement reaction method
Put copper(I) sulfate solution into four of the wells in the spotting tile.
Place a strip of magnesium into the first well of liquid, zinc into the second
iron into the third, and copper into the fourth. Leave for about a minute.
Note down any changes in the table below. If there is no change, write ‘no
change.
Repeat these steps replacing the copper sulfate solution with each of the other three solutions in turn.
What is metal ore?
When there is enough of a metal compound in a rock to make it worth extracting the metal, it is called a metal ore
Whethere it is worth extracting a particular metal depends on three things:
- How easy is it to extract from its ore
- how much metal the ore contains
- the changing demands for a particular metal
Do lots of metals react with oxygen to form oxides? If so are they the ores that metals have to be extracted from often?
Yes (example of oxidation) and yes
The formation of metal ore:
Oxidation- gain of oxygen
E.g. magnesium is oxidised to make magnesium oxide
2Mg + O2 ~ 2Mg0
Extraction of metal:
Reduction - loss of oxygen
E.g. copper oxide is reduced to copper
2Cu0 + C ~ 2Cu + CO2
How is metals extracted from their ores and how?
It is extracted chemically by reduction using carbon.
The ore is reduced as oxygen is removed from it, and carbon gains oxygen so its oxidised.
What is potassium, sodium, lithium, calcium, magnesium and aluminium extracted by and why?
Extracted by using electrolysis because carbon can only twke oxygen away from metals which are less reactive than carbon itself.
What is zinc, iron, tin, lead, copper extracted by.
It is extracted by reduction using carbon.
How is silver, gold and platinum extracted?
It isn’t. It is found native
Why is tungsten extrscted by reduction of oxide by hydrogen and not carbon?
Although carbon would be cheaper, it forms a compound tungsten carbide but if it is obtaned by redcurion of its oxide by hydrogen its pure.
What is a salt?
A salt is the general name for a compound formed when the hydrogen of an aocid is partially replaced by metal ions
What does zinc always form?
Zn2+ ions
The salts formed when you react a metal with hydrochloric acid , HCL, are?
Always chlorides (containing CL - ions)
What does sulfuric acid H2SO4 make?
Sulfurates (containing SO4 2- ions)
Nitric acid (HNO3) always makes?
Nitrates (containing NO3 - ions)
What does acid + base give
A salt + water
The reaction between acid and base is called
Nuetralisation
Neutralisation between acids and alkalis can be seen in terms of H+ and OH- ions:
From the acid h) ( from the alkali oh)
H+ + OH- ~ H20
What is the formulae of salts?
They are made up of positive metal ions and a negative ion from an acid.
What are bases
Oxides or hydroxides
Making a copper salt RP METHOD:
1) Using a measuring cylinder, measure 20cm3 of acid into the beaker.
2) stand the beaker on a tripod and gauze and warm gently until it is almost boiling. Then turn bunsen off.
3) Add half a spatula of copper(II) oxide power into the acid and stir using the glass rod.
4) Continue adding the copper(II) oxide until no more dissolves. When the copper(II) oxide disappears the solution is clear blue.
5) Allow the apparatus to cool completely and then filter the mixture and discard the residue.
6) Pour the filtrate into an evaporating basin. Evaporate this gently using a water bath (250cm3 beaker with boiling water) on the tripod and gauze (see diagram). Stop heating once crystals start to form.
7) Remove the evaporating basin from the heat and leave to crystallise.
8) Record what you observed when:
• Copper(II) oxide was first added to the acid.
• Excess copper(II) oxide was added.
• The salt was left to crystallise.
Metal oxides and metal hydroxides are:
Soluble compounds are alkalis
Acid + alkali ~
Acid + alkali ~ salt + water
What are metal carbonates?
Bases
Acid + metal carbonate ~
Acid + metal carbonate ~ salt + water + carbon dioxide
Example of acid + metal carbonate ~ salt + water + carbon dipxide
Hydrochloric acid + sodium carbonate ~ sodium chloride + water + carbon dioxide
Acid + alkali ~ salt + water example
Hydrochloric acid + copper oxide ~ copper chloride + water
Acid +base ~ salt + water example
Hydrochloric acid + solid iron oxide ~ iron chloride solution + water
What is an acid?
Its a substance that forms aqueous solutions with a ph of less than 7. They form H+ ions in water
A base is?
A substance with a ph greater than 7
An alkali is?
A base thst dissolves in water to form a solution with a ph greater than 7. Alkalis form OH- ions in water
Water
HCL ~
Water
HCL ~ H+ + Cl-
When an acid nuetralises a base, the products are?
Nuetral, i.e. they have a ph of 7.
Whats can an indicator be used for?
An indicator can be used to show that a nuetralisation reaction is over
What is the ph scale:
A measure of how acidic or alkaline a solition is.
The lower the ph of a solution, the more acidic it is.
The higher the ph of a solition, the more alkaline it is.
A neutral substance has ph7
What is an indicator?
An indicator is a dye that changes colour depending on whether it’s above or below a certain pH. Some indicators contain a mixture of dyes that means theycgradually change colour over a broad range of Ph.
What else pther than an indicator can measure Ph
pH probe attached to a pH meter can also be used to measure pH electrically. The probe is placed in solution you are measuring and the pH is given on a digital display as a numerical value, meaning irs more accurate than an indicator
What are strong acids?
Strong acids ionise completelt in water. All acid particles dissociate to release H+ ions
What are weak acids?
Theycdo not fully ionise in solution. Only a small proportion of acid particles dissociate to release H+ ions
The ionisation of a weak acid is
A reversible reaction, which sets up an equilibiprium between the undissociated and dissociated acid.
Reactions with acids involve H+ ions reacting with
Other 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
The ph of an acid or alkali is a measure of the concentration of H+ ions
the concentration of H+ ions in the solution
For every decrease of 1 on the Ph scale, the concentration of H+ ions increases by
A factor of 10.
The general rule for the increase by factor of 10 in relation to ph is
Factor H+ ion concentration changes by = 10 to the power of -x (x is the amount the ph falls by
Fill the gaps:
The pH of a strong acid is always ________ than the pH of a _________ acid if they have the same ___________
Less, weaker, concentration
What does concentration measure?
The concentration measure how much acid there is in a certain volume of water.
What does acid strength tell you?
Twlls you what proportion of the acid molecules ionise in water
Ph will ______ with increasing acid concentration regardless of whether its a ______ or ______ acid
Decrease, strong, weal
