Topic 3- Part one Acids Flashcards by Artemis Buxton

What are acids a source of?

Hydrogen ions

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What are alkali’s a source of?

Hydroxide ions

OH-

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3 indicators?

-Methyl Orange
-Phenolphthalein
-Litmus

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What colour does litmus turn?

universal indicator orange

1) Acid- Red

2) Alkali- Blue

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What colour does Methyl Orange turn?

orannge

1) Acid- Red

2) Alkali- Yellow

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What colour does phenolphthalein turn?

colourless

1) Acid- Colourless

2) Alkali- Pink

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When is smth more acidic/alkali?

Higher conceentration of H+/OH- oins which lowers/increases the pH

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How much does the concentration have to change for the pH by one

x10 (more H+/OH- ions)

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Core Practical: Investigate the change in pH on adding by powdered calcium hydroxide or calcium oxide to a fixed volume
of dilute hydrochloric acid

1) Measure 50cm^3 of 1mol dm^-3 HCl into a beaker
2) Measure pH using universal indicator (gradual change)
3) Measure 0.25g calcium hydroxide
5) Add calcium hydroxide + measure pH
6)Repeat until total of 2.5g of calcium hydroxide added

more alkali as OH-

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Concentrated vs dilute?

1) Larger amount of substance in given volume
2) Less

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What is a strong acid?

One that fully dissociates (breaks down) into h+

HCl, HNO3

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What is a weak acid?

-Doesnt fully dissociate

Ethanoic acid, CH3OOH

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Acid + Base

a base is any substance that reacts with an acid to make?

—> salt + water

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What are alkalis

soluable bases

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Metal + Acid

—> Salt + Hydrogen

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Metal oxide + Acid

—-> Salt + water

Metal Hydroxide + Acid

—-> Salt + Water

Metal carbonate + Acid

—-> Salt + water + carbon dioxide

Chemical test for Hydrogen?

-Place a burning splint into gas
-Will produce a squeaky pop sound if hydrogen

Chemical test for Carbon dioxide?

Bubble gas through limewater (calcium hydroxide) and goes cloudy

What is a neutralisation reaction?

Between acid + base (alkali)

Salt + water

What happens in a neutralisation reaction?

H+ and OH- ions react to form water

When we react insoluable salt + acid why do we add excess salt?

Ensure all acid has reacted

salt is insoluable so wont react with water produced

How and why do we remove excess salt in insoluable reactant + acid reaction?

-Done by filtration
-leave only salt + water

What do we do if we want to produce a soluable salt from an insoluable reactant and acid?

1) Add excess insoluable salt (ensure all acid has reacted) 2) Filter off excess (insoluable so wont dissolve in produced water) 3) Evaporate water in water bath

What do we do if we want to produce a soluable salt from a soluable reactant and an acid?

- **Titration** (becuase exact measurement is needed as excess reactants are unable to be removed) 1) Add **alkali** solution into conical flask 2) Add indicator e.g **phenolphthalein** 3) Should be pink 4) Add Acid to titration buiret 5) Add drop by drop till **colourless** (neutral) 6) Use **activated charcole** to remove indicator 7) Filter of insoluable charcole + indicator 8) Heat + evaporate for salt crystals

Core practical: How to make copper sulphate from copper oxide?

1) Add excess copper oxide (insoluable) to sulphuric acid 2) Filter funnel and filter paper to filter excess 3) Evaporate off water by placing in water bath 4) Leave salt

Which type of salts are all soluable?

all nitrates

Which type of salts are mostly soluable?

- Most sulfates - Most Halogens (7 e.g chlorine/iodine)

Which sulfates are insoluable? | se..., .engthy, .lack,.ock

-Lead sulphate -Barium sulphate -Calcium sulphate | lead, barium, calcium

Which halogens ar insoluable?

- Reacted with silver or lead | Fluorine, Bromine, Iodine, Astatine, Tennessine

Which carbonates and hydroxides are soluable?

-Sodium -Potassium -Ammonium

Which carbonates and hydroxides are insoluable?

All others apart from -Sodium -Potassium -Ammonium

What are precipitates?

Insoluable solids formed from change in solution | e.g if a carbonate of hydroxide salt is formed it will be a precipitate

How to get insoluable salt?

1) Mix wanted solutions together 2) Filter for insoluble residue 3) Clean with distillled water 4) Leave to dry or evaporate using drying oven