C5.1 - C5.8 Chemical Changes✔️ Flashcards

1
Q

What is the reativity series?

A

Is a list of metals in order of their reactivity with most reactive at the top-least at the bottom

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2
Q

Features of metal ores?

A

Most metal ores chemicaly bonded to other elements in compounds - many have been oxidised - to form their oxides eg Iron(III) Oxide

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3
Q

What does it mean if a metal is oxidised?

A

Oxidised - have oxygen added usualy from oxygen in the air to form oxides

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4
Q

How do you extract metals from their oxides?

A

Metal oxide must be reduced - have oxygen removed

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5
Q

How do you test for hydrogen gas with a beaker and lighted splint?

A

There will be a ‘pop’ sound when hydrogen gas comes into contact with lighted splint

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6
Q

Potassium to calcium reaction with water?

A

-Fizz
-gives of hydrogen gas leaving an alkaline solution of metal hydroxide

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7
Q

Mangensium to iron reaction with water?

A

-very slow reaction

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8
Q

Tin and leads reaction with water?

A

-slight reaction with steam

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9
Q

Copper,silver,gold reaction with water?

A

-no reaction

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10
Q

Potassium,sodium,lithium reaction with dilute acid?

A

Explode

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11
Q

Magnesium,aluminium,zinc,iron reaction with dilute acid?

A

-fizz giving off hydrogen gas
-forming a salt

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12
Q

Tin and lead reaction with dilute acid?

A

-React slowly with warm acid

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13
Q

Copper,silver,gold reaction with dilute acid?

A

No reaction

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14
Q

How are metal ordered on the rectivity series?

A

-in order of reactivity by their reactions with water and dilute acid

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15
Q

What will displace a less reactive metal from an aqueous solution of its salts?

A

A more reactive metal will displace a less reactive metal from an aqueous solution of one of its salts.

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16
Q

What does an ionic equation show?

A

Shows only the atoms an ions that change in a reaction

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17
Q

Why does zinc displace lead?

A

Zinc is more reactive the lead - higher on reactivity series - therefore zinc displaces lead from its solution.

Zinc (s) + lead nitrate (aq) - zinc nitrate (aq) + lead (s)

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18
Q

What is oxidation?

A

Oxidation - loss of electrons

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19
Q

What is reduction?

A

Reduction - gain of electrons

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20
Q

Why is carbon used to extract ores?

A

Carbon(non-metal) also displaces less reactive metals from their oxides - used to extract metals from ores

Metal oxide + carbon —–> metal + carbon dioxide

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21
Q

What is a purpose of the reactivity series?

A

Helps you decide best way to extract a metal from its ore - oxides of metals below carbon in series can be reduced by carbon to give metal element

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22
Q

What determines weather metal is worth extracting?

A

-how easy it is to extract from ore
-how much metal ore cotains
-changing demands for a particular metal

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23
Q

Why are Gold and silver found in the earth as metals?

A

They are so unreactive that they exist in their native state

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24
Q

How are metals more reactive then carbon extracted?

A

Metals more reactive then carbon are not extacted via reduction but by electrolysis of the molten metal compound

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25
Q

What is a salt?

A

A Salt is a compound formend when the hydrogen in an acid is wholly,or partially replaced by metal ions

26
Q

Equation and example of formation of salt?

A

Metal + acid - a salt + hydrogen

Iron + hydrochloric acid - iron(II)chloride + hydrogen

27
Q

How can pure dry salts be extracted from their solution?

A

The water is evaporated from the solution by heating it until the point of crystalisation is reached - solution now saturated and crystals will appear

28
Q

How to test for crystals in a solution?

A

Dip a glass rod into the hot salt solution - removing it and seeing if crystals form on it as it cools

29
Q

How are salts made?

A

Salt can be made by reacting a suitable metal with an acid - metal must be above hydrogen in reactiviy series but not to reactive

30
Q

Why type of reaction is a metal and an acid?

A

Example of a redox reaction - metal atoms loose electrons and are oxidised and hydrogen ions from the acid gain electrons and are reduced

31
Q

what are bases?

A

Bases are compounds that can neutralise acds - alkalis are bases that are insoluble in water eg the hydroxides of group 1 metals - lots of bases are metal oxides

32
Q

What is formend when you react an acid and a base?

A

A salt and water are produced

Acid + base - a salt + water

33
Q

What is the equation for neurtalisation?

A

Acid + base - a salt + water

34
Q

What are salts made up of?

A

Made up of positive metal ions and a negatie ion from a an acid - positive ions come from a metal,base or carbonate

35
Q

What is the overall charge of salts?

A

Like all ionc compounds they have no overall charge - as sum of charges on their ions equal zero

36
Q

How do you make copper sulfate crystals?

A

1)Add insoluble coper oxide to sulfuric acid - stir - warm on a tripod and gauze
2)solution turns blue - shows copper sulfate is being formend - excess black copper oxide can be seen
3)when reaction complet - filter - removed excess copper oxide
4)evaporate water - so crystals of copper sulate can form - stop heating when first crystals appear - leave rest of water to evaporate slowly - gives larger crystals - filter any small excess with fiter paper

37
Q

Equation for making copper sulfate crystals?

A

Sulfruic acid + copper(II) oxide - copper(II) sulfate + water

38
Q

Reactions to make salts?

A

A soluble salt can be prepared by reacting an acid with a suitable insoluble reatant including:
-a metal
-a metal oxide
-a carbonate

39
Q

Why is it hard to tell when an acid and an alkali have completley reacted?

A

-no gas given off which would stop when acid had been neutralised
-no excess insoluble base visible

40
Q

How do you tell when an acid and alkali have completley reacted?

A

You need to use an acid/base indicator

41
Q

What happens when an acid and alkali reacts?

A

A neutralision reaction occurs

Acid + alkali - a salt + water

42
Q

What happens when an acid and base react?

A

Neutralisation reaction occurs?

Acid + base - a salt + water

43
Q

What happens when an acid and carbonate react?

A

Give a salt , water and carbon dioxide

Acid + a carbonate - a salt + water + carbon dioxide

44
Q

What do you do to collect a pure,dry sample of crystal?

A

-carry out titration with the indicator added - see how much acid reacts completley with the alkali

-run that volume of aid into the solution of alkali again without indicator this time

-crystalise and dry crystals of salt from reaction mixture.

45
Q

What are alkalis?

A

Soluble hydroxides are called Alkalis,example sodium hydroxide solution

46
Q

What are bases?

A

Base Include alkalis and are substances that can neutralise acids - metal oxides and metal hydroxides are bases

47
Q

What is an acid?

A

An acid is a substance that produces hydrogen ions, H +(aq), when dissolved in water an example is sulfuric acid

48
Q

It pure water acidic or alkaline?

A

Pure water is neutral pH 7

49
Q

What happens when you add acid into water ?

A

All acids release H+ ions into solution when added to water - these excess H+ ions make solution acidic

50
Q

What type of ions do all alkalis form when added to water?

A

All alkalis form aqueous hydroxide ions OH- when added to water these excess OH- ion makes a solution alkaline

51
Q

Name and example of an indicator?

A

Litmus example of an indicator - turns red in acid - blue in alkaline

52
Q

What is the pH scale?

A

Scale shows how acidic or alkaline a solution is - 0 most acidic - 14 most alkaline - can use universal indicator to find pH of a solution - pH7 is neutral

53
Q

What is a pH meter?

A

Glass probe attached to dip in solution being tested - some electronic pH sensors give digital display of pH directly - or attached to computer to monitor pH changes overtime

54
Q

What happens to acids in water eplain in terms of mollecules?

A

In water all acids ionise (split up) , their mollecules split up to from H+ ions and negative ions - all acidic solutions have H+ ions

55
Q

What is a strong acid?

A

Lower pH value - ionise completley in solution - reaction is not reversiable

56
Q

What is a weak acid?

A

Higher pH value - most of the molecules stay as they are - do not release H+ ions into solution - reaction is reversible

57
Q

What happens to mollecules in a weak acid?

A

Small portion split up to form H+ ions and negative ions - the ions recombine to form orginal molecules again - position of equalibrium is reached

58
Q

How much does concentration of H+ ions increase by?

A

Concentration of H+ ions increase by a factor of 10 the pH value decreases by one unit.

Or

Concentration of H+ decreases by a factor of 10 the pH value increases by one unit

59
Q

What are H+ ions?

A

Hydrogen ions

60
Q

Why can copper chloride not be produced by reacting copper with hydrochloric acid?

A

Copper is less reactive on the reactivity series and can not displace hydrogen

61
Q

How are metals more reactive then carbon extracted from their ores?

A

Electrolysis of the molten metal compound