Acids and Bases

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Sophia

Cards (19)

  • Acids and bases dissolve in water; in fact, most liquids are either an acid or a base.
  • An acid is a substance that produces hydrogen ions and an anion salt, for example, Hydrochloric acid (HCl) → H+ + Cl-.
  • A base is a substance that produces hydroxide ions and a cation salt, for example, Sodium hydroxide (NaOH) → Na+ + OH-.
  • A solution with equal amounts of H+ and OH- ions is considered neutral, for example, Water (H2O) → H+A + BOH- → AB + H2O.
  • Both acids and bases release ions when dissolved in water, hence they are aqueous.
  • The ionic bonds are not strong enough to hold the ions together in water.
  • Formulas of acids typically contain Hydrogen, for example, HNO4, HCl, H2SO4.
  • Most bases contain hydroxide, for example, NaOH, Ca(OH)2, LiOH.
  • Substances containing the compound ammonium are also bases, for example, Ammonium Nitrate (NH4NO3).
  • Two very common indicators used by chemists are Litmus Paper and Universal Indicator.
  • Litmus Paper changes colour in acidic and basic solutions, for example, Red Litmus Paper in acidic solution, Blue Litmus Paper in basic solution.
  • Universal Indicator is a chemical which is made of several compounds that change colour based on pH.
  • Many house and garden materials can be used as acid/base indicators, for example, Red cabbage is often used to create indicators.
  • Almost any flower, fruit, or plant part that is red, blue, or purple contains pigments called anthocyanins, these compounds change colour when in acidic or alkaline (basic) solutions.
  • The pH scale measures the hydrogen ions in a solution, pH stands for “potential of hydrogen”.
  • The pH scale is a tool used to measure the acidity or alkalinity of a solution.
  • Acids have a pH between 0-6.9, Bases have a pH between 7.1-14.
  • The pH scale is exponential, a one unit change on the pH scale corresponds to a ten-fold increase in the concentration of H+ ions, meaning each pH value that is less than 7 is ten times more acidic than the previous one.
  • Compare the acidity of solutions with a pH of 6, pH of 3.