Acids, Bases and Salts 7 Science — Revision Notes
Acids and bases are chemical compounds with opposite properties, while salts result from their neutralization. Understanding these substances is crucial fo
TL;DR: Acids and bases are chemical compounds with opposite properties, while salts result from their neutralization. Understanding these substances is cruci…
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Acids and bases are chemical compounds with opposite properties, while salts result from their neutralization. Understanding these substances is crucial fo
Key Points to Remember
- Acids are substances that taste sour, turn blue litmus red, and have pH less than 7
- Bases are substances that taste bitter, turn red litmus blue, and have pH greater than 7
- Salts are ionic compounds formed when acids react with bases in neutralization
- pH scale measures acidity and basicity from 0 to 14, with 7 being neutral
- Indicators are substances that change color to show presence of acids or bases
- Litmus paper turns red in acids and blue in bases
- Methyl orange turns red in strong acids and yellow in neutral or basic solutions
- Phenolphthalein turns colorless in acids and pink in bases
- Hydrochloric acid, sulfuric acid, and acetic acid are common acids
- Sodium hydroxide, potassium hydroxide, and ammonia are common bases
- Neutralization is the reaction between acids and bases producing salt and water
- Universal indicator solution shows a range of colors for different pH values
Important Formulas
- Acid + Base = Salt + Water
- pH = -log[H+]
- pOH = 14 - pH (relationship in water)
Key Terms
- Acid: Substance that tastes sour and turns blue litmus red, with pH below 7
- Base: Substance that tastes bitter and turns red litmus blue, with pH above 7
- Salt: Ionic compound formed from neutralization of an acid and base
- pH: Measure of acidity and basicity on a scale from 0 to 14
- Indicator: Substance that changes color in presence of acids or bases
- Neutralization: Chemical reaction between acid and base producing salt and water
Frequently Asked Questions
How do you identify if a substance is an acid or a base?
Use litmus paper or indicators: acids turn blue litmus red and have sour taste; bases turn red litmus blue and have bitter taste. pH less than 7 indicates acid, greater than 7 indicates base
What happens when acid and base react?
Acids and bases undergo neutralization, producing a salt and water. The hydrogen ions from acid combine with hydroxide ions from base, forming neutral water
What is the pH scale and why is 7 neutral?
pH scale ranges from 0 to 14, measuring acidity. pH 7 is neutral because it represents equal concentrations of hydrogen and hydroxide ions, as in pure water
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