C5- Chemical changes ⚗️
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What happens when a metal reacts with oxygen ?
• when a metal reacts with oxygen, it forms a metal oxide and a oxidation reaction takes place.
What is a oxidation
• Oxidation is a reaction that involves gaining oxygen. • [oxidation is the loss of electrons; the gain of oxygen]
What does OIL RIG stand for ?
• oxidation is, loss of electrons and gain of oxygen. • reduction is, gain of electrons and loss of oxygen.
What is reduction ?
• reduction is a reaction involving the loss of oxygen. • [reduction is the gain of electrons]
What is the mnemonic for remembering the reactivity series ?
• Please- potassium • Stop- sodium • Lazily- lithium • Calling- calcium • Me- magnesium • A- aluminium • Careless- carbon • Zebra- zinc • Instead- iron • Try- tin • Learn- lead • How- hydrogen • Copper • Saves- silver • Gold
How does: pottasium, sodium and lithium react with water ? Hint: at room temperature
• potassium, sodium and lithium will react very rapidly with water, at room temperature.
How does: pottasium, sodium and lithium react with acids ?
• potassium, sodium and lithium react dangerously fast with acids.
• Fill in the gaps: when ______ react, they ____ electrons, forming a positive ion. • And the reactivity of a metal, depends on its ability to ____ electrons and form a ________ ion.
• when metals react, they ,lose electrons, forming a positive ion. • And the reactivity of a metal, depends on its ability tolose electrons and form a positively charged ion.
Where are unreactive metals such as gold found ? 🧈
• unreactive metals such as gold, are found in the Earth as the metal itself.
What will a more reactive element do to its compound ?
• a more reactive element, will displace [push out] a less reactive element, from its compound.
How can we extract metals that are more reactive than carbon ?
• metals that are higher on the reactivity series than carbon, can be extracted using electrolysis of the molten metal compound- which will extract those metals, from their ore.
What is a ore ? Hint: a rock
• an ore is, a rock with a large amount of metal compound.
How can metals that are less reactive than carbon be extracted ?
• metals that are less reactive than carbon can be extracted, from their oxides, by reduction with carbon.
In aqueous solutions, what do acids produce ?
• in aqueous solutions, acids produce hydrogen ions [H+]. • ; acid molecules ionise [split] in aqueous solutions, and release H+ ions.
How does the amount of free H+ ions affect the pH ? Hint: opposite
• if there are more H+ ions= the acid will be stronger, having a lower pH. • ; if there are less H+ ions= the acid will be weaker, and have a higher pH.
What is a base ? Hint: producing Hint #2; not ions
• a base is a chemical that can neutralise acids, producing a salt and water. • Bases are typically metal oxides or metal hydroxides.
What is an alkali ? Hint: dissolves
• an alkali, is a base that dissolves in water. [soluble in water]
In aqueous solutions, what do alkalis produce ?
• in aqueous solutions, alkalis produce hydroxide ions [OH^-]
What is the pH scale ? Hint: tells us
• the pH scale, tells us the acidity or alkalinity of a solution. • acids have a pH between 0 and 6, solutions with a pH of 7 and neutral and alkalis have a pH between 8 to 14.
How can we determine the pH of a solution ?
• we can determine the pH of a solution, using a pH probe- which determines the pH electronically. • or by using universal indicator [or litmus paper]
What colour does litmus paper turn, in an acid or an alkali ?
• acid= red • alkali= blue
What does universal indicator tell you ?
• universal indicator tells you the pH to 0.5, and: • in a neutral solution: green is shown • in a acid: red is shown • and in a alkali: blue/purple is shown.
What is a neutralisation reaction ?
• neutralisation is a reaction between an acid and an alkali. • the hydrogen ions will react with hydroxide ions to produce water. • H+ (aq) + OH- (aq)————> H2O (l)
What is the equation for neutralisation ? Hint: ions
• the equation for neutralisation is: • H+ (aq) + OH- (aq)————> H2O (l)