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Acids and Bases. 12/01/12. Acids. The word “acid” comes from the Latin word for sour Acids tend to have a sour taste Acids turn blue litmus paper red Their pH value is lower than 7 on the pH scale. In your body Stomach acid. In the lab (Strong Acids) Sulphuric acid. In your home
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Acids and Bases 12/01/12
Acids • The word “acid” comes from the Latin word for sour • Acids tend to have a sour taste • Acids turn blue litmus paper red • Their pH value is lower than 7 on the pH scale In your body Stomach acid In the lab (Strong Acids) Sulphuric acid In your home Lime juice
Bases • Bases are the opposite to acids • Bases have a soapy feel • Bases turn red litmus paper blue • Bases have a pH greater than 7 on the pH scale • An alkali is a base which is soluble in water In your body Urine In the lab Sodium hydroxide In your home Bleach
Indicators • Indicators are substances which change colours depending whether they are in acidic or basic substances • The most well known indicator is called litmus paper. • Litmus paper turns red in acids and blue in bases • Universal indicators are a mixture of different indicators and change different colours depending on the strength of acids or bases
pH scale • The pH scale indicates the acidity or bacidity of a solution. • It runs from 0 to 14 • 7 is neutral (pure water) • Acids have a pH value lower than 7 on the pH scale • Bases have a pH greater than 7 on the pH scale