Acids, Bases, Salts, and Electrolysis

• Acids, bases, and salts are fundamental chemical compounds and interactions.
• Electrolysis uses electricity to break down compounds.
• Chemical reactions involve energy changes, either releasing or absorbing it.
• Oxidation and reduction are complementary processes that involve the transfer of electrons.

Acids

• Acids produce hydrogen ions (H+) when dissolved in water.
• Acids taste sour
• Acids turn blue litmus paper red.
• Acids have a pH less than 7.
• Strong acids completely dissociate in water.
• Weak acids only partially dissociate.
• Hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid (HNO3) are common acids.
• Acids react with metals to produce hydrogen gas and a salt.
• Acids react with carbonates to produce carbon dioxide, water, and a salt.
• Acids are used for cleaning, etching, and fertilizer production.

Bases

• Bases produce hydroxide ions (OH-) when dissolved in water.
• Bases taste bitter and feel slippery.
• Bases turn red litmus paper blue.
• Bases have a pH greater than 7.
• Strong bases completely dissociate in water.
• Weak bases only partially dissociate.
• Sodium hydroxide (NaOH), potassium hydroxide (KOH), and ammonia (NH3) are common bases.
• Bases neutralize acids, forming a salt and water.
• Bases are used for cleaning and manufacturing soaps.

Salts

• Salts are ionic compounds formed from the reaction between an acid and a base (neutralization).
• Salts typically are crystalline solids at room temperature.
• Salts generally are soluble in water, though solubility varies.
• Salts are neutral compounds with a pH close to 7.
• Sodium chloride (NaCl), potassium nitrate (KNO3), and calcium carbonate (CaCO3) are common salts.
• Salts are used in food preservation, fertilizers, and chemical manufacturing.

Electrolysis

• Electrolysis uses an electric current to drive a non-spontaneous chemical reaction.
• An electrolytic cell consists of two electrodes (anode and cathode) immersed in an electrolyte solution.
• The anode is the electrode where oxidation occurs (loss of electrons).
• The cathode is the electrode where reduction occurs (gain of electrons).
• Ions in the electrolyte solution carry electric charge between the electrodes.
• Positive ions (cations) migrate to the cathode, and negative ions (anions) migrate to the anode during electrolysis.
• Electrolysis decomposes compounds into constituent elements.
• Electrolysis applications include metal extraction, electroplating, and production of chlorine and sodium hydroxide.

Energy Change

• Chemical reactions involve changes in energy.
• Energy can be released (exothermic reactions) or absorbed (endothermic reactions).
• Exothermic reactions release energy, increasing the temperature in the surroundings.
• Endothermic reactions absorb energy, decreasing the temperature in the surroundings.
• The enthalpy change (ΔH) measures heat energy exchanged during a reaction at constant pressure.
• ΔH is negative for exothermic reactions because energy is released.
• ΔH is positive for endothermic reactions because energy is absorbed.
• Activation energy is the minimum energy required for a reaction to occur.
• Catalysts speed up reactions by lowering activation energy.

Oxidation and Reduction

• Oxidation and reduction are complementary chemical processes involving electron transfer.
• Oxidation is the loss of electrons.
• Reduction is the gain of electrons.
• Oxidation and reduction always occur together in a redox reaction.
• An oxidizing agent accepts electrons and causes oxidation.
• A reducing agent donates electrons and causes reduction.
• Oxidation numbers are assigned to atoms to track electron movement in redox reactions.
• Combustion, rusting, and respiration are examples of redox reactions.
• LEO says GER: Lose Electrons Oxidation, Gain Electrons Reduction.
• OIL RIG: Oxidation Is Loss, Reduction Is Gain.