Gen 6 - Acids and Bases Flashcards Preview

GAMSAT March 2016 > Gen 6 - Acids and Bases > Flashcards

Flashcards in Gen 6 - Acids and Bases Deck (45)
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31

What is a neutralisation reaction ? 

When acids and bases react with each other, forming a salt and water. 

32

What is a Bronsted base ? 

The salt of a weak acid 

33

What is Kh of a salt ? 

The hydrolysis constant of the salt. 

 

34

What is the equation for a strong acid + a strong base ? 

E.g. HCl + NaOH

HCl + NaOH ⇔ NaCl + H2O

N.B. Salts in which the cation and anion are both conjugates of a strong base and a strong acid form neutral solutions. 

35

What is the equation for strong acid and a weak base ? 

E.g. HCl + NH3

HCl + NH3 ⇔ NH4Cl

 

N.B. Salts that are formed based on a strong acid and a weak base for acidic solutions. 

36

What is the equation for a weak acid and a strong base ? 

E.g. HOAc + NaOH

HOAc + NaOH ⇔ NaOAc + H2O

37

What is the equation for a weak acid and a weak base ? 

E.g. HOAc + NH3

HOAc + NH3 ⇔ NH4OAc

The pH is dependent on the relative strengths of the acid and the base 

38

What is a buffer ? 

A solution that resists change in pH when a solution is diluted , or a small amount of acid or base is added. 

39

What does a buffer solution consist of ? 

A mixture of a weak acid and its salt, or a weak base and its salt. 

40

Why are buffers made up of weak acids/bases, and not strong ? 

Strong acids/bases do not have any buffering capacity as the dissociation would be irreversible. 

41

When is the buffering capacity of a solution at its maximum ? 

When pH = pKa

42

What is an amphoteric species ? 

A substance, e.g. water, that can act as either an acid or a base. Many metal oxides and hydroxides also act amphoterically. 

43

What is the general purpose of a titration reaction ?

To determine the concentration of a given sample of acid or base (analyte). 

44

What is the end/equivalent point of a titration ? 

They are not always the same thing. 

The end point is where a physical change in solution (e.g. colour) occurs. 

The equivalence point is where a reaction is theoretically complete. 

In practice, this difference can usually be seen as negligable. 

45