acids, bases & PH chp 20 Flashcards

1
Q

what is a Bronsted-lowry acid

A
  • acid dissociate and release H+ ions In aqueous solution
  • Bronsted-lowry acid is a proton donor
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2
Q

what is a bronsted-lowry alkali

A
  • dissociates into OH- ions in aqueous solution
  • proton acceptor
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3
Q

what is a conjugate acid-base pair

A
  • contains 2 species that can be interconverted by transfer of a proton
  • In the forward direction, HCl (a conjugate base) releases a proton to form its conjugate, base, Cl-
  • in the reverse direction, Cl- accepts a proton to form its conjugate acid, HCl
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4
Q

in this reaction how does each species act as either an acid or an alkaline

A

in the forward direction
- HCl is an acid as it donates H+
- OH- is a base and it accepts H+

in the reverse reaction
- H20 is an acid ac it donates H+
- Cl- is a base as it accepts H+

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5
Q

when could water act as a base

A
  • can accpet protons from HCl to form H3O-
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6
Q
  • What is meant by the terms monobasic, dibasic and tribasic
  • give examples for each
A
  • refers to the total numbers of hydrogen ions in the acid that can be replaced per molecule
  • HCl = monobasic
  • H2SO4 = dibasic
  • H3PO4 = tribasic
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7
Q

what are some examples of mono basic, dibasic and tribasic acids

A
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8
Q

what is an ionic equation

A

A equation that shows the charges of the important elements involved

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9
Q

what are spectator ions

A

ions that do not change charge during the reaction, spectator ion is sulfategroup below

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10
Q

what type of reaction is the reaction between acids and metals

A
  • redox reactions
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11
Q

what type of reaction is the reaction between neutralisation of acids with carbonates,metal oxides and alkalise

A

neutralisation

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12
Q

What does pH measure

A

hydrogen ion concentration

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13
Q

what do concentrations of hydrogen ion meant for pH

A
  • A low value of [H+(aq)] matches a high value of pH
  • A high value of [H+(aq)] matches a low value of pH
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14
Q

whats the formula for pH and [H+]

A
  • pH=-log(10)[H+(aq)]
  • [H+(aq)]= 10^-pH
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15
Q

how do the pH values differ

A
  • pH of 1 has 10 time the concentration of H+ ions as a solution with a pH of 2
  • to dilute a solution from a pH 1 to a pH of 4 qwould require dilution by 10x10x10=1000 times
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16
Q

how do the [H+] and [HA] relate when talking about strong acids

A

they are equal

17
Q

what is Ka, what is its formula

A
  • the acid dissociation constant
  • it is Kc applies to the dissociation of an acid
18
Q

what do the values of Ka tell us

A
  • higher the Ka is further the equilibrium is to the right and the stronger the acid
    ^as acid dissociates more and gives larger value
19
Q

what is the formula for pKa and the reverse formula

A
20
Q

How do the strength of acids relate to the values of Ka and pKa

A
  • the stronger the acid, the larger the Ka value and the smaller pKa value
  • the weaker the acid the smaller the Ka value and the larger the pKa value
21
Q

what’s the difference between a weak and strong acid

A
  • a strong acid HA completely dissociates
  • a weak acid HA partially dissociates
22
Q

what does the [H+] depend upon for a weak acid

A
  • concentration of acid
  • acid dissociation constant, Ka
23
Q

what are the assumptions made when calculating the Ka for a weak acid

A
  • Assumption 1: The dissociation of water to form H+ ions is negligible when compared to H+ formed from acid
  • Assumption 2:You can assume that HA > [H+], You can neglect any fall in concentration of HA from dissociation
24
Q

How do you calculate pH using the Ka expression

A
25
Q

Assumptions made when using calculations involving weak acids

A
  • assumption 1: dissociation of water is negilible
  • assumption 2: assumes the concentration of acid is much greater than the [H+] at equilibrium
26
Q

how can water act both as a base and an acid

A
27
Q

how can water act both as a base and an acid

A
  • called ionic production of water
  • can accepts hydrogen ions and acts as a base.
  • can donate hydrogen ions and acts like as acid
28
Q

From what can the pH of strong bases be calculated

A
  • the concentration of the base
  • the ionic product of water Kw