Chapter 4 - Acids and Redox

salt

a compound formed when the H⁺ ion in an acid is replaced by a metal ion or other positive ion

neutralisation reactions

an acid is neutralised by a base to form water

-AASHO, BASHO, CASHOCO

features of acids

-all contain hydrogen

-all release H⁺ ions when dissolved in water - are proton donors

-H⁺ ions make the solution acidic

STRONG + WEAK acids

-strong = high concentration of H⁺ ions, low pH, fully dissociates (no bonded atoms/all separate atoms)

-weak = low concentration of H⁺ ions, higher pH, partially dissociates (some bonded atoms + some separate atoms)

ACIDS FORMULAE -hydrochloric acid

HCl

-sulphuric acid

H₂SO₄

-nitric acid

HNO₃

-ethanoic acid

CH₃COOH

alkali

-releases OH^- ions in aqueous solution

-are bases where the OH- ion accepts a H+ ion to make water - proton acceptors

base

a substance which readily accepts a H+ ion from an acid

ALKALIS FORMULAE -sodium hydroxide

NaOH

-ammonia

NH₃

reduction

-electrons are gained
-decreases oxidation number

oxidation

-electrons are lost
-increases oxidation number

EXCEPTIONS of oxidation numbers

-oxygen in fluorine = becomes +2

-oxygen in H₂O₂ (peroxide) = becomes -1

-hydrogen with metals = becomes -1

gdm^-3 → moldm^-3

/ Mr

moldm^-3 → gdm^-3

x Mr