Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry GCSE > Acids & Electrolysis Topic 3 > Flashcards

Acids & Electrolysis Topic 3 Flashcards

(54 cards)

Start Studying
1
Q

What does a strong acid contain

A

Lots of H+ ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is pH a measure of

A

How many H+ ions are present in the solution
The more H+ ions the lower the pH ( more acidic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does a low pH mean

A

Acidic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does a high pH mean

A

Alkali

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Metal + acid =

A

Salt + hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When an ACID is added to LITMUS INDICATOR what colour change is seen

A

Dark red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When an ALKALI is added to LITMUS INDICATOR what colour change is seen

A

No colour change - stays dark blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When an ACID is added to PHENOPHTHALEIN INDICATOR what colour change is seen

A

No change - stays colourless

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When an ALKALI is added to PHENOPHTHALEIN INDICATOR what colour change is seen

A

bright pink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When an ACID is added to METHYL ORANGE INDICATOR what colour change is seen

A

Red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When an ALKALI is added to METHYL ORANGE INDICATOR what colour change is seen

A

Yellow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a concentrated acid

A

More H+ ions per volume of solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a dilute acid

A

Less H+ ions per volume of solution (more water)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a base

A

Substances that neutralise acids to form a salt and water only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give the generic equation for the neutralisation of an acid using a base

A

Metal oxide + acid ——> salt + water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe what happens during a neutralisation reaction with a metal oxide

A

During neutralisation hydrogen ions in the acid combine with oxide ions to form water. This removes the hydrogen ions and so the pH increases (becomes more neutral)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Give the products of the neutralisation reaction :
Tin oxide + hydrochloric acid

A

Tin chloride + water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How many times more hydrogen ions are there in an acid with a pH of 4 compared to an acid with a pH of 2

A

100 (every jump in pH is x10)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When obtaining dry crystals of copper sulphate why is the copper oxide added in excess

A

To make sure all the acid has reacted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the final step to get the dry salt crystals (neutralisation reaction)

A

Scrape out onto filter paper and blot them dry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Metal + acid =

A

Salt + hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Metal carbonate + acid =

Study These Flashcards
A

Salt + carbon dioxide + water

23
Q

What is titration a method of

Study These Flashcards
A

Neutralisation

24
Q

How do you obtain a soluble salt from an alkali (neutral solution left over from titration)

Study These Flashcards
A

By crystallisation

25
Are nitrates soluble in water
Yes all of them
26
Are chlorides soluble in water
Yes most apart from silver and lead chlorides (insoluble)
27
Are sulphates soluble in water
Most apart from lead, barium and calcium sulphates (insoluble)
28
Are carbonates soluble in water
Most are INSOLUBLE apart from sodium, potassium and ammonium carbonates
29
Are hydroxides soluble in water
Most are IBSOLUBLE Apart from sodium, potassium and ammonium hydroxides
30
Are salts soluble in water
Yes all common sodium potassium and ammonium salts are
31
What is the method to form an INSOLUBLE SALT from two soluble salts
Mix the two soluble salts in a beaker and then filter. Rinse beaker with distilled water and pour through funnel Pour distilled water over precipitate in funnel Carefully remove filter paper and dry in warm oven
32
What is the method to form a soluble salt Core practical
Add excess metal oxide to acid Gently warm in a water bath to speed up the reaction Filter to remove the unreacted solid from the solution Heat the solution to evaporate water and concentrate the salt solution Leave to crystallise
33
Concentration =
no.moles ÷ volume (dm^3)
34
Why must titration be used to obtain a solution of a salt and water only, when using an acid and an alkali?
Because there is no insoluble excess reactant that could be removed by filtration.
35
Describe the method of a titration
Use the pipette and pipette filler to ADD a MEASURED VOLUME OF ALKALI TO a CONICAL FLASK ADD a few DROPS of INDICATOR and put the CONICAL FLASK ON a WHITE TILE FILL the BURETTE with ACID and NOTE the start VOLUME. SLOWLY ADD ACID from the burette TO THE ALKALI in the conical flask, SWIRLING to mix. STOP WHEN the indicator first PERMENANTLY CHANGES COLOUR). NOTE the FINAL VOLUME. REPEAT steps 1 to 5 until you get concordant titres (2dp). More accurate if added drop by drop.
36
What criteria do the products need to fulfil if a precipitate is to form
If AT LEAST 1 of the products meets the insoluble rule a precipitate will form
37
What are ionic compounds made out of
Charged particles (anions & cations)
38
When can ionic compounds conduct electricity and why
They can conduct electricity only when molten or dissolved Can’t conduct when in a solid state as their ions are in fixed positions
39
What charge does the cathode have
Negative
40
What charge does the anode have
Positive
41
Would Chlorine be attracted to the anode or the cathode
Anode because chlorine is negatively charged and so would be attracted to positively charge anode
42
What is electrolysis
Electrolysis is a process in which electrical energy, from a direct current supply, decomposes electrolytes.
43
At which of the electrodes will an oxidation reaction occur
At the positively charged ANODE (OILRIG) Oxidation is loss of electrons
44
At which of the electrodes does a reduction reaction occur 
At the negatively charged CATHODE (OILRIG) Reduction is gain of electrons
45
When the substance is electrolysed IN SOLUTION what does it mean
That an extra OH- and H+ are produce (water)
46
What is the rule at the cathode for electrolysis in solution
Cation that is less reactive is reduced Eg. If metal is lower than hydrogen in the reactivity series you get the metal If hydrogen is lower then you get hydrogen instead of the metal
47
What is the rule at the anode for electrolysis IN SOLUTION
If you have halides (group 7 ions) the halogen is produced With other common negative ions you get oxygen
48
What do you have to remember about group 7 molecules when balancing half equations
They are DIATOMIC (eg. Not Cl but Cl2)
49
What are the 3 elements less reactive than hydrogen on the reactivity series
Copper Silver Gold (These are the only 3 elements that would win and be part of the half equation for electrolysis in solution)
50
Describe the method for electrolysis using copper electrodes
Pour copper sulphate solution into beaker Measure and record mass of 2 copper (foil) electrodes Attach one to the positive terminal and one to the negative terminal (making sure you know which one correspond to which mass) Turn on power supply & leave for 20 mins Remove 1 of the electrodes, rinse with distilled water and then dip it into propanone. Then lift it out and allow liquid to evaporate until dry. Repeat with other electrode Record mass of each and then calculate change in mass You can repeat this experiment at different currents
51
Which of the copper electrodes gains mass?
Cathode (negative electrode) COPPER IS DEPOSITED
52
Which of the copper electrodes loses mass?
Anode (positive electrode) COPPER DISSOLVES
53
For the electrolysis with copper electrodes describe the change in mass as the current is increased
As the current is increased the change in mass of the electrodes becomes greater
54
Why are copper electrodes used in electrolysis
To purify copper

Chemistry GCSE (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions