Acids, Bases, and Salts (C8)

Question 1

What is an acid

Answer 1

Compound which when dissolved in water produces hydrogen ions (H+)
Proton donors

Question 2

What colour do acids turn litmus paper to

Answer 2

Turns blue litmus indicator paper red

Question 3

What pH do acids have

Answer 3

1-6

Question 4

Name the 3 general equations of an acid

Answer 4

Acid + metal -> salt + hydrogen gas
Acid + base -> salt + water
Acid + metal carbonate -> salt + carbon dioxide + water

Question 5

Name a property of ionizing strong and weak acids

Answer 5

Strong: completely ionize in water producing lots of H+ ions
Weak: partially ionize in water producing few H+ ions

Question 6

What is a base

Answer 6

Insoluble substances which neutralize acids to form a salt
proton acceptors
Alkali

Question 7

What colour do bases turn litmus paper to

Answer 7

Turns red litmus indicator paper blue

Question 8

What pH do bases have

Answer 8

8-14

Question 9

Name the 2 general equations of a base/alkali

Answer 9

Base + acid -> salt + water (+ carbon dioxide is base is metal carbonate)
Base + ammonium salt -> salt + ammonia gas + water

Question 10

Name a property of ionizing strong and weak bases

Answer 10

Strong: completely ionize in water producing lots of OH- ions (NaOH, KOH)
Weak: partially ionize in water producing OH- ions (NH4OH)

Question 11

What is the pH of a neutral substance

Answer 11

7

Question 12

Name 3 points of acidity in soil

Answer 12

Plants grow at a pH near 7
Will not grow if pH is too acidic or alkaline
Acidic soil is fixed by adding lime

Question 13

What is pH

Answer 13

Concentration of H+ ions per dm3 of solution

Question 14

What are the 5 indicators and what colour do they turn in acid and alkaline

Answer 14

Indicator:
Phenolphthalein
Methyl orange
Methyl red
Red litmus
Blue litmus

Colour in acid:
Colourless
Pink
Red
Red
Red

Colour in alkaline:
Pink
Yellow
Yellow
Blue
Blue

Question 15

What are the 2 types of oxides

Answer 15

Metal oxides (basic) (iron oxide/magnesium oxide)
Non-metal oxides (acidic) (sulphur oxide/carbon dioxide)

Question 16

Name 2 neutral oxides

Answer 16

Oxides that are neither acidic or basic are neutral

Water/carbon monoxide

Question 17

What is a salt

Answer 17

Substance formed when all the replaceable hydrogen ions of an acid are replaced by metal ions or the ammonium ion
Soluble or insoluble

Question 18

Name 6 soluble salts

Answer 18

All sodium potassium and ammonium salts
All nitrates
Chlorides
Sulphates
Potassium, sodium, ammonium carbonates

Question 19

Name 3 insoluble salts

Answer 19

Chlorides except silver and lead
Sulphates accept barium, lead, calcium
All other carbonates except potassium, sodium, ammonium carbonates

Question 20

Name 4 types of salt required and acid used to make them

Answer 20

Sulphate: sulphuric acid
Nitrate: nitric acid
Chloride: hydrochloric acid
Ethanoate: ethanoic acid

Question 21

What do you need to do when starting with a metal to make a salt

Answer 21

Add excess metal to an acid
When bubbling (hydrogen), stop the reaction is done
Filter off excess metal

Question 22

What do you need to do when starting with an insoluble base to make a salt

Answer 22

Add insoluble base to acid and heat gently, it will dissolve
Keep adding until no more dissolves (reaction is done)
Filter out insoluble excess base

Question 23

What do you need to do when starting with an alkali (titration)

Answer 23

Put a certain amount of alkali in a flask
Add phenolphthalein
Add acid from a burette, stirring, until it goes colourless
Find out how much acid you used
Repeat, to be more accurate
Evaporate water from neutral solution

Question 24

What do you need to do when starting with a precipitation

Answer 24

Mix the two soluble salts, so they react together
Filter the mixture to separate the products produced (soluble and insoluble salt produced)
Wash the insoluble salt on filter paper
Dry the insoluble salt in a warm oven

Question 25

What are the 7 cations used to test for aqueous cations and its effects of AQ. NaOH and AQ. Ammonia

Answer 25

Aluminum (Al3+): white soluble precipitate, colourless: white precipitate formed Ammonium (NH4+): ammonium gas produced turns red litmus blue: no effect Calcium (Ca2+): white precipitate formed: no precipitate/slight white precipitate Copper (Cu2+): Light blue precipitate formed: light blue soluble precipitate formed giving dark blue solution Iron (II) (Fe2+): green precipitate: green precipitate Iron (III) (Fe3+): red-brown precipitate: red-brown precipitate Zinc (Zn2+): white soluble precipitate, colourless: white precipitate, colourless

Question 26

What are the 6 anions used for anion tests and results

Answer 26

Carbonate (Co32-): add dilute nitric acid: bubble gas (Co2) through limewater- from colourless to cloudy Chloride (Cl-): nitric acid, then aq. silver nitrate: white precipitate Bromide (Br-): nitric acid, then aq. silver nitrate; cream precipitate Nitrate (No3-): aq. sodium hydroxide, then aluminium: gas turns red litmus paper blue Sulphate (So42-): dilute nitric acid, then aq. barium nitrate: white precipitate

Question 27

What are the 5 tests for gases and test results

Answer 27

Ammonia (NH3): red litmus paper turns blue Carbon dioxide (Co2): bubble gas through- from colourless to cloudy Chlorine (Cl2): bleaches red/blue litmus paper Hydrogen (H2): place lighted splint, squeaky pop Oxygen (O2): place glowing splint, splint relights