acids & bases Flashcards
Acid + reactive metal =
salt + hydrogen gas
eg 2HCl(aq) + Zn(s) = ZnCl2(aq) + H2
acid + metal hydroxide
salt + water
eg: H2SO4(aq) + 2NaOH(s) + = Na2SO4(aq) +2H2O
Acid + metal oxide
salt + water
H2SO4(aq) + MgO(s) = MgSO4(aq) + H2O
acid + metal carbonate
salt + water + CO2
2HCl(aq) + Na2CO3(aq) = 2NaCl(aq) + H2O(l) + CO2(g)
acid + metal sulfite
salt + water + sulfur dixoxide
2HCl(aq) + Na2SO3(s) = 2NaCl(aq) + H2O(l) + SO2
Ammonium salt + base
salt + ammonia + water
eg: 2NaOH(aq) + (NH4)2SO4(aq) = Na2SO4(aq) + 2NH3(g) +2H2O
base + non-metal oxide
salt + water
Properties of Acids
Litmus paper becomes red
Corrosive
Sour
Reacts with bases
Ph less than 7
Conducts electricty
Properties of Bases
Litmus paper becomes blue
Caustic and Slippery
Bitter
Reacts with Acids
Ph more than 7
Conducts electricity
Arrhenius model
States that
- An acid is a substance that ionises in water to produce a hydrogen ion or proton
- A base is a substance that dissociates in water to form hydroxide ions
MonoProtic acids
can only form one H+ ion for each molecule of acid
Diprotic acids
(H2SO4 and H2CO3) acids that can produce two H+ ions for each molecule of acid
Triprotic acids
(H3PO4 and H3BO3) acids can produce three H+ ions for each molecule of acids
Strong acids/base
The term strong acid/base refers to how much an acid/base ionises in water
strong acid/base ionises completely in water
eg. NaOH –> Na(aq) + OH(aq)
Weak acid/base do not ionise completely in water
Example of Strong acids & Bases
Acids PH 1-3
HCl (hydrochloric acid
HNO3 (nitric acid)
H2S04 (Sulfuric Acid)
Bases PH 11-14 :
NaOH (Sodium Hydroxide)
KOH (potassium Hydroxide)
Ba(OH)2 (barium Hydroxide)
Example of Weak Acids & Bases
Acids Ph of 4-6
CH3COOH ) acetic acid
H2CO3 (CARBONATE acid)
H3PO4 (Phosphoric acid)
Bases Ph 8-10
NH3 (ammonia
CH2 NH2 (methyl amine)
Limitations of Arrhenius
does not explain how certain materials like CO2 and SO2 form acidic solutions when dissolved in water,despite having no hydrogen atoms & materials like NH3 and NaCO3 form basic solutions when mixed with water, despite not having OH groups
BrØnsted-Lowry Model
shows how these species produce hydrogen ions or hydroxide ions in solutions by reacting with water in a process called hydrolysis.
Indicator
a material that is altered by the presence of an acid or base
Universal Indicator
mixture of several different indicators providing a good range of colours when tested with acids and bases
