Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A Chemistry IGCSE course > Acids, alkalis and salts > Flashcards

Acids, alkalis and salts Flashcards

1
Q

What colour is:

Universal indicator

A

Neutral - green
Acid - Red
Alkali - Blue

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

What colour is:

Litmus

A

Acid-Red
Alkali - Blue

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

What colour is:

Methyl orange

A

Acid - red
Alkali - Yellow
Neutral - Orange

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

What colour is:

Phenolphthalein

A

Acid - colourless
Alkali - pink

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

What different groups are there in the pH scale:

A

0-3 strongly acidic - hydrochloric acid
4-6 weakly acidic - vinegar
7 - neutral - water
8-10 weakly alkaline - ammonia solution
11-14 - strongly alkaline - sodium hydroxide solution

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

is carbon dioxide acidic?

A

Yes, because it reacts in water to form carbonic acid

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

What are alkalis?

A

Soluble bases, as it needs to be dissolvable in water to be acidic/alkaline. These are also proton acceptors as they react with H+ to form H2O

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

What are the different equations for metals and acids?

A

Metal + acid -> salt + hydrogen
Metal oxide + acid -> Salt + water
Metal hydroxide + acid -> Salt + water
Metal carbonate + acid -> Salt + water + carbon dioxide
Ammonia + acid -> Salt (contains ammonium)

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

what is a neutralisation reaction?

A

When bases, e.g. metal oxides react with acids which neutralises to form water. OH+H=H2O

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

What is a titration?

A

When a neutralisation reaction occurs between bases and alkalis where the reactant’s volumes are measured

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

What are acids usually described as?

A

proton donors as they dissociate with a hydrogen ion which gives water a proton as H+ has just a proton

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

What are bases described as?

A

Proton acceptors as they react with H+ (a proton). e.g., hydroxide accepts H+ to form water

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

What are alkalis?

A

soluble bases that form OH- in water

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

How can it be determined if dilute acids react with a metal?

A

Depending on the position in the reactivity series. The reaction is more vigorous up the series.

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

Characteristics of strong and weak acids

A

Strong acid Weak acid
Nature Fully dissociated Partially dissociated
Examples Hydrochloric acid Ethanoic acid
Reaction with Mg Lots of bubbles, warm Some bubbles
Reaction with carbonates Bubbles Fewer bubbles
Colour of universal indicator with typical solution Red Orange -red

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

What are the different methods of forming soluble and insoluble salts

A

soluble salt from acid and alkali (titration)
soluble salt from an acid and insoluble base/metal/carbonate (crystallisation)
insoluble salt from two soluble salt (precipitation reaction)

17
Q

Steps for making a soluble salt from an acid and an insoluble base

A
  1. add excess solid to the acid (to neutralise all the acid) and stir
  2. filter to remove excess solid when all acid has been neutralised
  3. Heat pure salt solution to evaporate some of the solution which concentrates the solution until some crystals form
  4. cool, leading to crystals forming (as at lower temperatures less solute can be dissolved in a solvent) and then filter to separate out the crystals
  5. Dry salts in warm oven
18
Q

What are the steps for titration?

A
  1. add 25cm^3 of alkali/acid to a conical flask using a volumetric pipette. Add 4 drops of indicator
  2. use a burette to add acid/alkali till the first permanent colour change(swirl at the same time)
  3. Repeat the titration 3 times doing it drop by drop when the end point is approaching
  4. Do a titration without indicator adding the average volume of acid : alkali
  5. Heat pure salt solution to evaporate some of the solution which concentrates the solution until some crystals form
  6. cool, leading to crystals forming (as at lower temperatures less solute can be dissolved in a solvent) and then filter to separate out the crystals
  7. Dry salts in warm oven
19
Q

Method for making an insoluble salt from 2 soluble parts

A
  1. combine equal quantities of two solutions and stir
  2. filter out the salt crystals (residue)
  3. wash crystals with pure distilled water
    dry salt crystals in warm oven
20
Q

What is solubility measured as?

A

grams that will dissolve in 100 degrees of water at a specific temperature

21
Q

what is the formula with moles, vol and conc

A

moles = vol * conc

22
Q

what would be on the x and y axis of a solubility curve

A

y axis - g/100 g of water
x axis - temperature

23
Q

How to find out:

volume of acid to neutralise an alkali

A
  1. add indicator in conical flask, as well as 25cm^3 of alkali with volumetric pipette and add in acid using a burette
  2. stop when colour change occurs (ideally name colour change)
  3. start value - end value gets change in volume
  4. do dropwise/swirling/repeating and using concordont results

A Chemistry IGCSE course (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions