Reactivity 3.1 Proton Transfer Reactions

What happens when protons are transferred?

R3.1 Proton Transfer Reactions

Skills Focus

Understand how to accurately measure the following to an appropriate level of precision: pH of a solution
Show awareness of the purpose and practice of acid–base and redox titration
Carry out calculations

UNDERSTANDINGS

R3.1.1—Brønsted–Lowry acid is a proton donor and a Brønsted–Lowry base is a proton acceptor.
- - - Deduce the Brønsted–Lowry acid and base in a reaction.
R3.1.2—A pair of species differing by a single proton is called a conjugate acid–base pair.
- - - Deduce the formula of the conjugate acid or base of any Brønsted–Lowry base or acid.
R3.1.3—Some species can act as both Brønsted–Lowry acids and bases.
- - - Interpret and formulate equations to show acid–base reactions of these species.
R3.1.4—The pH scale can be used to describe the [H+] of a solution: pH = –log10[H+]; [H+] = 10–pH
- - - Perform calculations involving the logarithmic relationship between pH and [H+].
R3.1.5—The ion product constant of water, Kw, shows an inverse relationship between [H+] and [OH–]. Kw = [H+] [OH–]
- - - Recognize solutions as acidic, neutral and basic from the relative values of [H+] and [OH–].
R3.1.6—Strong and weak acids and bases differ in the extent of ionization.
- - - Recognize that acid–base equilibria lie in the direction of the weaker conjugate.
R3.1.7—Acids react with bases in neutralization reactions.
- - - Formulate equations for the reactions between acids and metal oxides, metal hydroxides, hydrogencarbonates and carbonates.
R3.1.8—pH curves for neutralization reactions involving strong acids and bases have characteristic shapes and features.
- - - Sketch and interpret the general shape of the pH curve.

MAKING CONNECTIONS

Nature of science, Reactivity 3.4—Why has the definition of acid evolved over time?

Structure 2.1—What are the conjugate acids of the polyatomic anions listed in Structure 2.1?

Structure 3.1—What is the periodic trend in the acid–base properties of metal and non-metal oxides?

Structure 3.1—Why does the release of oxides of nitrogen and sulfur into the atmosphere cause acid rain?

Tools 1, 2, 3—What is the shape of a sketch graph of pH against [H+]?

Nature of science, Tool 2—When are digital sensors (e.g. pH probes) more suitable than analogue methods (e.g. pH paper/solution)?

Reactivity 2.3—Why does the extent of ionization of water increase as temperature increases?

Reactivity 2.3—How would you expect the equilibrium constants of strong and weak acids to compare?

Reactivity 1.1—Why does the acid strength of the hydrogen halides increase down group 17?

Tool 1, Inquiry 2—What physical and chemical properties can be observed to distinguish between weak and strong acids or bases of the same concentration?

Tool 1, Structure 1.1—How can the salts formed in neutralization reactions be separated?

Reactivity 1.1—Neutralization reactions are exothermic. How can this be explained in terms of bond enthalpies?

Reactivity 3.2—How could we classify the reaction that occurs when hydrogen gas is released from the reaction between an acid and a metal?

Structure 1.4—Why is the equivalence point sometimes referred to as the stoichiometric point?

Tools 1 and 3, Structure 1.3—How can titration be used to calculate the concentration of an acid or base in solution?