Science 9 Unit 2 Test Ultimate Study Guide

Particle Model of Matter

All matter is composed of extremely tiny particles called atoms, which can combine to form molecules.

States of Matter

The three forms of matter: solids, liquids, and gases, characterized by the arrangement and energy of particles.

Solids

Particles possess low energy, remain very close together due to strong attractive forces, and maintain a fixed shape.

Liquids

Particles possess moderate energy, can move past one another, and take the shape of their container while maintaining a constant volume.

Gases

Particles possess high energy, have weak attractive forces, move freely, and expand to fill their container.

Pure Substances

Consist of only one type of particle (e.g., $Fe$, $C_6H_{12}O_6$).

Homogeneous Mixtures (Solutions)

Uniformly scattered particles; typically clear and cannot be separated by filtration (e.g., Windex).

Heterogeneous Mixtures (Mechanical Mixtures)

Particles are not uniformly scattered; distinct parts are visible and remain mixed (e.g., granite).

Physical Change

Alters the form or state of a substance without changing its chemical composition; no new substance is created.

Chemical Change

Changes the chemical identity to create one or more new substances; this change is not reversible.

Indicators of a Chemical Reaction

Heat is produced or absorbed; change in $pH$; starting material is consumed; change in colour; gas bubbles form; a precipitate forms.

Physical Properties

Characteristics observed or measured without forming a new substance, including qualitative and quantitative properties.

Chemical Properties

Characteristics describing how a substance reacts with other substances.

Subatomic Particles

Protons, neutrons, and electrons that make up an atom.

Atomic Number

Total number of protons in the nucleus of an atom, which equals the number of electrons in a neutral atom.

Ions

Formed when neutral atoms gain or lose valence electrons to achieve stability; can be anions (negatively charged) or cations (positively charged).

Periodic Table

Organizes all known elements in horizontal periods and vertical groups based on similar properties.

Metals

Solids at room temperature, shiny, malleable, ductile, good conductors of heat and electricity.

Non-metals

Brittle solids or gases at room temperature, dull appearance, poor conductors.

Chemical Bond Types

Molecular (Covalent) Compounds involve sharing electrons; Ionic Compounds involve electron transfer.

IUPAC Nomenclature

System used to name chemical compounds based on specific rules.

Chemical Equations

Represent the reactants and products in a chemical reaction; structured as $\text{Reactants} \rightarrow \text{Products}$.

Endothermic Reactions

Absorb energy during bond breaking, typically requiring heat.

Exothermic Reactions

Release energy during bond formation, usually resulting in a temperature rise.

Reaction Rate

The speed at which a chemical process occurs, influenced by factors such as temperature and concentration.

Catalyst

Substance that increases the reaction rate without being consumed.

Enzymes

Biological catalysts that accelerate chemical reactions in living organisms.