Acids and Bases Flashcards
Properties of acids
Hydrogen Ions: Acids release ( H+) cations when dissolved in water.
Taste: Typically sour.
Corrosiveness: Corrosive in nature.
pH Range: Less than 7 (pH 1-6).
Indicator Reaction: Turns blue litmus paper red and universal indicators red.
Electrolytes: Conduct electricity.
Properties of bases
Hydroxide Ions: Bases release ( OH- ) anions when dissolved in water.
Taste: Typically bitter.
Caustic Nature: Can cause chemical burns.
pH Range: Greater than 7 (pH 8-14).
Indicator Reaction: Turns red litmus paper blue and universal indicators blue.
Feel: Soapy and slippery.
Electrolytes: Conduct electricity.
Partial disosciation
Weak acids and bases only partially dissociate.
Full disosciation
Strong acids and bases dissociate completely in water.
High concentration
High Concentration: Indicates a high proportion of acid/base molecules relative to water.
Low concentration
Low Concentration: Indicates a low proportion of acid/base molecules relative to water.
pH scale and indicators
pH Scale: Measures the acidity or basicity of a solution.
Acids: pH < 7
Bases: pH > 7
Neutral substances: pH = 7 (e.g., water)
Indicators: Chemicals that change color based on the pH of the solution (e.g., litmus paper, universal pH indicators).
Neutralisation
Hydrogen ions (acid) combine with hydroxide ions (base) to
form water. Water is considered neutral (pH 7).
H+ + OH- H2O
Reaction with metals
Acid + metal salt + hydrogen gas.
Reaction with carbonates
Acid + metal carbonate salt + water + carbon dioxide gas.
Stomach acid and indigestion
Hydrochloric acid in the stomach kills harmful bacteria
which may have been ingested.
● Hydrochloric acid also activates an important digestive
enzyme (pepsin)
● Occasionally the Hydrochloric acid concentration in the
stomach is imbalanced and may cause indigestion
● If the acid moves up the oesophagus it may cause ‘heartburn’
Symtoms of indigestion
pain, a burning feeling, or discomfort in your upper abdomen
● feeling full too soon while eating a meal
● feeling uncomfortably full after eating a meal
Treaments of indigestion with anatacids
Antacids are tablets or liquid medicines to relieve indigestion / heartburn:
○ Contain bases or carbonates that neutralise acid
○ May float on top of the acidic contents of your stomach- neutralise
and prevent acid from rising.
○ Common examples: Calcium carbonate / Magnesium carbonate
/ Aluminium hydroxide / Magnesium hydroxide
Examples of acids and their uses
HCl Hydrochloric acid Kills bacteria in the stomach - Strong
H2SO4 Sulfuric acid Used in the liquid in car batteries - Strong
CH3COOH Acetic acid
(Ethanoic acid) Vinegar - Weak
Examples of bases and their uses
NaOH Sodium hydroxide drain and oven cleaner;
produce soap - Strong
Ca(OH)2 Calcium hydroxide cement - Strong
Mg(OH)2Magnesium hydroxide Antacid(relieves constipation and heartburn) - Weak
Reaction with bases
Acid + base salt + water
