Acids, Bases, and Chemical Reactions

• Acids release hydrogen ions when dissolved.
• Bases release or accept hydrogen ions when dissolved.
• pH expresses the acidity of a substance.
• Salt is produced by the reaction of an acid with a base.
• Electrolysis is a chemical change effected by passing an electric current through a substance.
• A fuel cell generates electricity via an electrochemical reaction, not combustion.
• An ion is an atom or group of atoms with an electric charge (positive or negative).
• A cation is a positively charged ion.
• An anion is a negatively charged ion.

Combustion of Hydrogen

• The word equation is hydrogen + oxygen = water.

Hydrogen as an Energy Supply

• Benefits: clean energy and high energy density.
• Risks: leaks, high production costs, and inefficiency.

Properties of Acids

• Turns blue litmus paper red.
• pH below 7.
• Tastes sour.
• Donates hydrogen ions (H+) in solutions.

Properties of Bases

• Turns red litmus paper blue.
• pH above 7.
• Tastes bitter.
• Accepts hydrogen ions (H+) or donates hydroxide ions (OH-).

Acid and Metal Reaction

• Word equation: acid + metal = salt + hydrogen gas.
• Bases release hydroxide ions in solution.
• Acids release hydrogen ions.

Green Hydrogen Production

• Uses electricity from renewable sources (wind or solar) to split water into hydrogen + oxygen.
• This process is clean and produces no harmful emissions.

Grey Hydrogen

• Produced using natural gas via steam methane reforming.
• Advantages: cost-effective and high production volume.
• Disadvantages: carbon emissions, dependence on fossil fuels, and not a long-term solution.

Electrolysis of Water

• Breaking down water into oxygen and hydrogen using an electric current.
• Word equation: water = hydrogen + oxygen.

Hydrogen Production

• Advantages: sustainable, no CO2 emissions, can be stored and transported, and can be converted back into water and electricity.
• Disadvantages: high costs, high energy consumption, and lack of infrastructure to produce and transport.

Ionization

• The process where an atom or molecule gains or loses electrons, becoming an ion.
• Occurs in solutions, gases, chemical reactions, etc.

Hydrogen Fuel Cell Energy Production

• Combines hydrogen and oxygen to produce electricity and water.
• Hydrogen splits into protons and electrons.
• Electrons create an electrical current.
• Protons combine with oxygen to form water.