4. Acids and redox Flashcards by ramona <3

What is an acid?

A species that releases H+ ions in aqueous solution.

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Because acids release H+ ions and they are protons, therefore acids are also called ______ ______ .

Proton donors

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What is the ionic equation when acid is breaking down?

HA (aq) ⇌ H+ (aq) + A- (aq)

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What are the common acids and what are their formula?

hydrochloric acid (HCl)
sulphuric acid (H2SO4)
nitric acid (HNO3)
ethanoic acid (CH3COOH)
phosphoric acid (H3PO4)

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What is a diprotic acid? Give one example of a diprotic acid.

Acid that releases 2 H+ ions, eg. sulphuric acid (H2SO4) .

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What is a triprotic acid? Give one example of a triprotic acid.

Acid that releases 3 H+ ions, eg. phosphoric acid (H3PO4) .

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What is a base?

A compound that neutralises an acid to form a salt.

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What is an alkali?

A type of base that dissolves in water and releases OH- (hydroxide) ions in aqueous solution.

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Because bases accept a proton (H+ ion) from an acid, therefore bases are also called ______ _________ .

Proton acceptors

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What is the ionic equation when a base is breaking down?

BOH (aq) ⇌ B+ (aq) + OH- (aq)

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What are the common alkalis and what are their formula?

sodium hydroxide (NaOH)
potassium hydroxide (KOH)
ammonia (NH3)

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Are all alkalis bases?

Yes

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Are all bases alkalis?

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Is water an acid or a base? Why?

Water is amphoteric (兩性的) because it can act as both acid and base.

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What is the ionic equation when water acts as an acid and breaks down?

H2O (l) + B (aq) > OH- (aq) + HB+ (aq)

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What is the ionic equation when water acts as a base and breaks down?

H2O (l) + HA (aq) > H3O+ (aq) + A- (aq)

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What is a strong acid?

An acid that completely dissociates in solution and release all H+ ions.

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What is a weak acid?

An acid that partially dissociates in solution and releases some H+ ions.

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What is neutralisation?

The reaction of:
1. H+ and OH– to form H2O
2. acid and base to form salt

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Acid + base > ?

Water + salt

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What is the ionic equation of acid + base?

H+ (aq) + OH- (aq) > H2O (l)

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Metal + acid > ?

Salt + hydrogen

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What is the ionic equation of metal + acid?

2H+ (aq) + X (s) > X 2- (aq) + H2 (g)

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Metal oxide + acid > ?

Salt + water

What is the ionic equation of metal oxide + acid?

2H+ (aq) + O 2- (s) > H2O (l)

Metal hydroxide + acid > ?

Salt + water

What is the ionic equation of metal hydroxide + acid?

H+ (aq) + OH- (aq) > H2O (l)

Metal carbonate + acid > ?

Salt + water + carbon dioxide

What is the ionic equation of metal carbonate + acid?

2H+ (aq) + CO3 2- (aq) > H2O (l) + CO2 (g)

Metal hydrogencarbonate + acid > ?

Salt + water + carbon dioxide

What is the ionic equation of metal hydrogencarbonate + acid?

H+ (aq) + HCO3 - (aq) > H2O (l) + CO2 (g)

Ammonia + acid > ?

Ammonium salt

What is the ionic equation of ammonia + acid?

NH3 (aq) + H+ (aq) > NH4+ (aq)

What is titration?

A technique used to measure the volume of one solution that reacts exactly with another solution.

What can titration be used for?

1. finding the concentration of a solution 2. identification of unknown chemicals 3. finding the purity of a substance

What is a standard solution?

A solution of known concentration

What is a volumetric flask used to?

Make up a standard solution very accurately

How to work out the unknown information of a solute?

1. work out the mole of solute in the solution for which you know both the concentration and volume 2. use the equation to work out the mole of solute in the other solution 3. work out the unknown information of the solute in the other solution

What is oxidation number?

The number of electrons involved in bonding to a different element.

What does oxidation number do?

1. help to write formulae 2. balance electrons

What is the oxidation number of elements?

What is the oxidation number of O?

-2

What is the oxidation number of H?

What is the oxidation number of F?

-1

What is the oxidation number of Na+ and K+?

What is the oxidation number of Mg 2+ and Ca 2+?

What is the oxidation number of Cl-, Br- and I-?

-1

What is the oxidation number of H in metal hydrides?

-1

What is the oxidation number of O in peroxides?

-1

What is the oxidation number of O bonded to F?

What is the sum of the oxidation numbers equal to?

The total charge

When are Roman numerals used?

When an element forms ion with different charge

Why are Roman numerals used?

To indicate the magnitude of the oxidation number when an element may have compounds/ions with different oxidation numbers.

What is oxidation?

Loss of electrons and an increase in oxidation number.

What is reduction?

Gain of electrons and a decrease in oxidation number.

What is a redox reaction?

A reaction that involves both oxidation and reduction.

What does redox reaction involves in the transfer of?

Electrons

What is disproportionation?

When the same element is both oxidised and reduced during a reaction.