Queensland Year 12 Chemistry Introduction

Introduction to the Study of Chemistry

• Chemistry is the study of matter and the changes it undergoes.
• Matter is anything that has mass and occupies space.
• Chemistry involves observations, experiments, and the development of models to explain natural phenomena.
• The study of chemistry in Queensland Year 12 is specifically structured around chemical explanations in everyday life, and relating this to chemical reactions and equations.

Atomic Structure

• Atoms are the fundamental building blocks of matter.
• Atoms contain a nucleus, comprising protons and neutrons.
• Electrons orbit the nucleus in specific energy levels (electron shells).
• Protons have a positive charge, neutrons are neutral, and electrons have a negative charge.
• The number of protons in an atom defines the element.
• The atomic number is the number of protons.
• The mass number is the sum of protons and neutrons.
• Isotopes are atoms of the same element with different numbers of neutrons.

Periodic Table

• The periodic table organizes elements based on their atomic structure and properties.
• Elements in the same group (vertical column) have similar chemical properties.
• Elements in the same period (horizontal row) have increasing atomic numbers and varying properties.
• Metals typically form positive ions, while nonmetals typically form negative ions.

Bonding

• Chemical bonds hold atoms together in compounds.
• Ionic bonds form between metals and nonmetals through the transfer of electrons.
• Covalent bonds form between nonmetals by sharing electrons.
• Metallic bonds are formed by a "sea" of delocalised electrons surrounding metal ions.
• Properties of substances depend on the type of bonding and the structure of the resulting compounds.

Chemical Reactions

• Chemical reactions involve the rearrangement of atoms.
• Reactants are substances that undergo change.
• Products are substances formed from the reaction.
• Chemical equations represent chemical reactions, with reactants on the left and products on the right.
• Balancing chemical equations ensures that the same number of atoms of each element is present on both sides of the equation according to the Law of Conservation of Mass.
• Different types of chemical reactions exist, including synthesis, decomposition, single displacement, double displacement, combustion, neutralization, etc.
• Understanding and predicting the products of different types of chemical reactions is crucial.

Acids and Bases

• Acids are substances that release hydrogen ions (H⁺) in solution.
• Bases are substances that release hydroxide ions (OH⁻) in solution.
• The pH scale measures the concentration of hydrogen ions in a solution.
• pH values range from 0 to 14, with 7 being neutral.
• Acids have a pH less than 7, and bases have a pH greater than 7.
• Neutralisation reactions occur between acids and bases, producing salt and water.

Redox Reactions

• Oxidation involves the loss of electrons.
• Reduction involves the gain of electrons.
• Redox reactions are coupled processes where one substance is oxidised, and another is reduced simultaneously.
• Examples include combustion reactions, rusting, and the use of electrochemical cells (batteries).

Chemical Calculations

• Stoichiometry involves calculating quantities of reactants and products in a chemical reaction.
• Molar mass relates the mass of a substance to the amount of substance in moles.
• Moles, mass, and volume are linked.

Organic Chemistry (Introduction)

• Organic chemistry deals with compounds containing carbon.
• Carbon forms the basis of many important biological macromolecules.
• Different functional groups in organic compounds affect their properties and reactions.

States of Matter

• Matter exists in three principal states: solid, liquid, and gas.
• Solids have a fixed shape and volume.
• Liquids have a fixed volume but take the shape of their container.
• Gases have neither a fixed shape nor a fixed volume.
• There are transitions between these states, such as melting, boiling, and sublimation.

Rates of Reaction

• The rate of a chemical reaction is the speed at which reactants are consumed or products are formed.
• Rates of reaction are influenced by factors such as concentration, temperature, surface area, and catalysts.
• Catalysts speed up reactions without being consumed themselves.

Equilibrium

• Chemical equilibrium is a dynamic state where the rates of forward and reverse reactions are equal.
• The position of equilibrium describes the relative amounts of products and reactants at equilibrium, and is affected by factors such as temperature, pressure, concentration, and catalysts.

Environmental Chemistry

• Some chemical reactions have important impacts on natural systems.
• Exposure to certain chemicals can cause environmental problems.
• Acid rain is an example of an environmental impact from chemical reactions.