Topic 3 Chemical Changes(complete) Flashcards

1
Q

Solutions with ph lower than 7 are

A

Acids

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2
Q

Solutions with ph higher than 7 are

A

Alkaline

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3
Q

Neutral solution has ph of

A

7

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4
Q

Acids form what ions in water

A

H+

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5
Q

Alkalis form what ions in water

A

OH-

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6
Q

Stronger acids have higher/lower ph
Weaker acids have higher/lower ph

A

Stronger acids lower
Weaker acids higher

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7
Q

Stronger alkalis have higher/lower ph
Weaker alkalis have higher/lower ph

A

Stronger alkalis higher
Weaker alkalis lower

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8
Q

What colour is litmus in acidic ,alkaline and neutral solutions

A

Acidic red
Neutral purple
Alkaline blue

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9
Q

What colour is methyl orange in acidic ,alkaline and neutral solutions

A

Acidic red
Neutral yellow
Alkaline yellow

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10
Q

What colour is phenolphthalein in acidic ,alkaline and neutral solutions

A

Acidic colourless
Neutral colourless
Alkaline pink

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11
Q

If the concentration of H+ ions increase what happens to the ph

A

Ph will decrease

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12
Q

If the concentration of OH- ions increase what happens to the ph

A

Ph will increase

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13
Q

As the concentration of h+ ions increases or decreases by factor of 10 how much will ph change

A

Ph will increase or decrease by 1

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14
Q

If an acid is concentrated what does it mean

A

Means there is more acid per volume of water
Dilute acid meaning there is less acid per volume of water

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15
Q

What does it mean for an acid to be strong or weak

A

Strong acids dissociate completely in water to release H+ ions
Weak acids don’t dissociate completely in water

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16
Q

What is a base

A

Substance that reacts with an acid to produce salt and water

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17
Q

Alkalis are soluble bases

A
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18
Q

HCl + NaOH —> NaCl + H20
Acid + base —> Salt + Water

A

H+ + OH- —> H20

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19
Q

What is a salt

A

An ionic compound
Metal and non metal
Eg NaCl

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20
Q

Acid + Metal Oxide—->?

A

Salt +Water

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21
Q

Acid +Metal Hydroxide—->?

A

Salt +Water

22
Q

Acid + Metal—->?

A

Salt +Hydrogen

23
Q

Acid + Metal Carbonate —-> ?

A

Salt + Water + Carbon dioxide

24
Q

What is the test for hydrogen

A

Use lighted splint and place near what your testing for hydrogen and if you hear squeaky pop hydrogen is present

25
Q

What is the test for carbon dioxide

A

Bubble gas testing for carbon dioxide through limewater and is present if limewater turns cloudy

26
Q

What is the reaction between an acid and a base known as

A

Neutralisation reaction

27
Q

How is water made in neutralisation reactions

A

H+ ions from acid react with OH- ions from alkali

28
Q

When making soluble salts why do you first need to add excess reactant to the solution

A

To make sure all the acid has reacted and none leftover

29
Q

What do you do after adding excess reactant(base) to an acid and base and all acid has been neutralised

A

Use filtration to remove excess solid to be left with only salt and water from neutralisation reaction

30
Q

What must you add to solution during titration to know when acid and alkali have been neutralised

A

Use an indicator

31
Q

Measure out set amount of acid and add few drops of 1_____ into 2_____ flask with acid
Add alkali from the 3_____ into acid until colour change signalling the solution has been
4_____
Repeat until you get 5______ results

A

1 indicator
2 conical
3 burette
4 neutralised
5 concordant

32
Q

After you get concordant result from titration and repeat reaction using that result what do you do

A

Slowly evaporate water off
Filter out the solid and left with pure dry salt

33
Q

What is added under conical flash during titration to see colour change easier

A

White tile

34
Q

What should you do with flask to ensure the acid is distributed evenly in alkali in titration

A

Swirl the flask regularly

35
Q

Common salts of sodium potassium and ammonium (solubility?)

A

Soluble

36
Q

Nitrates(solubility?)

A

Soluble

37
Q

Chlorides (solubility?)

A

Soluble
Except silver and lead chloride

38
Q

Sulfates (solubility?)

A

Soluble
Except lead, barium and calcium sulfate

39
Q

Carbonates and hydroxides (solubility?)

A

Insoluble
Except sodium,potassium and ammonium ones

40
Q

What is a precipitation reaction

A

Reaction between 2 right soluble salts to make an insoluble one

41
Q

What insoluble salt could be made from this precipitation reaction
Lead nitrate + sodium chloride —->

A

Lead nitrate + sodium chloride —-> lead chloride + sodium nitrate
Lead chloride is the insoluble salt

42
Q

Describe the method use to make pure dry sample of insoluble salt lead chloride

A

Add lead nitrate to one test tube of water and shake thoroughly and same with sodium chloride
Mix the 2 substances and the lead chloride should precipitate out
With the new mixture do filtration and should be left with lead chloride in filter paper as it not soluble
Rinse the filter paper with water and leave to dry or scrape off

43
Q

What is an electrolyte

A

Ionic compounds in molten state or dissolved in water

44
Q

Define electrolysis

A

Process in which electricity decomposes an electrolyte

45
Q

Describe movement to both ions to each electrode

A

Cations move to the cathode
Anions move to the anode

46
Q

What will the electrolyte potassium chloride form at each electrode and why

A

Cathode :potassium (potassium ions have positive charge and are attracted to the negatively charged cathode )
Anode: chlorine (chlorine ions have negative charge and are attracted to positively charged anode )

47
Q

What reactions happen at the the anode and the cathode

A

Anode - negative ions are oxidised(lose electrons
Cathode -positive ions are reduced(gain electrons)

48
Q

Explain oxidation

A

Gain of oxygen
Loss of electrons

49
Q

Explain reduction

A

Loss of oxygen
Gain of electrons

50
Q

Write Hal equation for electrolysis of aluminium oxide at cathode and anode

A

Anode
O2- -2e—-> O
(Oxygen made)

Cathode
Al3+ + 3e ——> Al
(Aluminium made)

51
Q

Explain what happens during electrolysis to obtain pure copper using electrolyte copper sulfate

A

Cathode is made of pure copper and anode made of impure copper
At anode the impure copper turns into its cation and moves to the pure copper cathode
All over cations move to the pure copper cathode and become reduced(gain electrons)