SNC1W1 Chemistry, Electricity, and Biodiversity Exam Review

Fundamentals of Matter and Particle Theory

• Matter is defined as anything that has mass and takes up space (volume).

• The Particle Theory of Matter consists of five key postulates:

  1. All matter is made of tiny particles.

  2. Particles are always moving in a random and constant motion.

  3. There are spaces between the particles that make up matter.

  4. Particles attract each other; the closer they are, the stronger the attraction.

  5. Heating changes particle movement: as heat energy is added, particles move faster and spread further apart.

Properties and States of Matter

• States of Matter:

  • Solid: Particles are packed tightly together, usually in a regular pattern. Solids have a fixed shape and a fixed volume.

  • Liquid: Particles are close together with no regular arrangement. Liquids have a fixed volume but take the shape of their container.

  • Gas: Particles are far apart with no regular arrangement. Gases have no fixed shape and no fixed volume, expanding to fill whatever space is available.

• Physical Changes: A change in which the substance involved remains the same substance, even though its state or form may have changed (e.g., melting, boiling, or dissolving).

• Chemical Changes: A change in which the original substance is converted into one or more new substances with different physical and chemical properties (e.g., burning, rusting, or reacting with acid).

• Density: A physical property representing the mass per unit volume of a substance.

  • Mathematical Formula: $D = \frac{m}{V}$

  • Standard units include $\text{g/cm}^3$ for solids and $\text{g/mL}$ or $\text{g/cm}^3$ for liquids.

• Types of Observations:

  • Qualitative: Observations that use the five senses to describe qualities (e.g., "the gas is colorless," "the solid is malleable.")

  • Quantitative: Observations that involve numerical data and measurements (e.g., "the mass is $15.5\,g$," "the temperature is $373\,K$").

The Periodic Table and Atomic Structure

• Using the Periodic Table:

  • Element Name: The full name of the chemical element.

  • Element Symbol: A one- or two-letter abbreviation (e.g., $O$ for Oxygen, $Na$ for Sodium).

  • Atomic Number ($Z$): The number of protons found in the nucleus of an atom, which identifies the element.

  • Atomic Mass ($A$): The average mass of an atom's protons and neutrons.

• Classification of Elements:

  • Metals: Found on the left and central parts of the periodic table. They are generally shiny, malleable, and good conductors of stay heat and electricity.

  • Nonmetals: Found on the upper right side of the periodic table. They are generally dull, brittle, and poor conductors (insulators).

• Elements vs. Compounds:

  • Elements: Pure substances consisting of only one type of atom.

  • Compounds: Pure substances composed of two or more different elements chemically bonded in fixed proportions.

• Subatomic Particles:

  • Proton ($p^+$): Located in the nucleus; carries a positive charge ($+1$).

  • Electron ($e^-$): Located in shells/orbitals surrounding the nucleus; carries a negative charge ($-1$).

  • Neutron ($n^0$): Located in the nucleus; carries no charge ($0$).

• Counting Atoms in a Molecule: Atoms are counted by looking at the chemical formula. For example, in a molecule of glucose ($C_6H_{12}O_6$), there are $6$ Carbon atoms, $12$ Hydrogen atoms, and $6$ Oxygen atoms.

• Bohr-Rutherford Diagrams:

  • These diagrams show the nucleus (containing protons and neutrons) surrounded by concentric electron shells.

  • The first shell can hold a maximum of $2$ electrons.

  • The second and third shells can hold a maximum of $8$ electrons.

  • These diagrams allow for the identification of elements based on the number of protons and help observe valence electron patterns.

• Ionic vs. Molecular Compounds:

  • Ionic Compounds: Formed when a metal transfers one or more electrons to a nonmetal, resulting in electrostatic attraction between cations and anions.

  • Molecular (Covalent) Compounds: Formed when two or more nonmetals share electrons to achieve a stable electron configuration.

Electricity: Charging and Static Electric Charges

• Basics of Charging: An object becomes electrically charged when it gains or loses electrons. Since protons are fixed in the nucleus, only electrons move during the charging process.

  • Gaining electrons = Negative charge.

  • Losing electrons = Positive charge.

• Methods of Charging:

  • Friction: Two neutral objects are rubbed together, and electrons are transferred from the material with a weaker hold to the one with a stronger hold.

  • Contact (Conduction): A charged object touches a neutral object, and the charge is shared between them.

  • Induction: A charged object is brought near (but does not touch) a neutral object, causing the electrons in the neutral object to shift position, creating a temporary charge separation.

• Conductors vs. Insulators:

  • Conductors: Materials that allow electrons to flow through them easily (e.g., metals like Silver, Copper, and Gold).

  • Insulators: Materials that do not allow electrons to flow through them easily (e.g., Rubber, Glass, Plastic, and Wood).

• Law of Electric Charges:

  • Opposite charges attract ($+$ and $-$).

  • Like charges repel ($+$ and $+$; $-$ and $-$).

  • Charged objects attract neutral objects due to induced charge separation.

• Electroscopes: Scientific instruments used to detect moving or static electric charges.

  • Pithball Electroscope: Uses a small, lightweight ball to show attraction or repulsion.

  • Metal Leaf Electroscope: Uses thin metal leaves that move apart when a charge is introduced.

Electric Circuits and Current

• Electric Current: The measure of the rate of flow of electric charges (electrons) through a point in a circuit.

• Electric Circuit: A complete, closed path through which electric current can flow.

• Components of a Circuit and Their Symbols:

  • Source: Provides electrical energy (e.g., Battery or Cell).

  • Conductor: The wires that connect the components.

  • Load: The part of the circuit that converts electrical energy into other forms of energy (e.g., Lamp, Resistor, Motor).

  • Control Device: Used to turn the circuit on or off (e.g., Switch).

• Types of Circuits:

  • Series Circuit: A circuit where the components are arranged in a single loop. There is only one path for the electrons to follow. If the path is broken, current stops everywhere.

  • Parallel Circuit: A circuit where the components are arranged in multiple branches. There are multiple paths for the electrons to follow. If one branch is broken, current can still flow through the others.

Biodiversity and Ecosystem Dynamics

• Ecosystem: A community of living organisms interacting with each other and their physical, non-living environment.

• Factors in an Ecosystem:

  • Biotic Factors: Living parts of an ecosystem, such as plants, animals, fungi, and bacteria.

  • Abiotic Factors: Non-living parts of an ecosystem, such as sunlight, air, water, soil, and temperature.

• Easter Island: A historical case study illustrating how the over-consumption of natural resources and loss of biodiversity can lead to the collapse of an entire ecosystem and society.

• Trophic Levels: The levels of a food chain or food web.

  1. Producer (Autotroph): Organisms that produce their own food through photosynthesis (e.g., plants, algae).

  2. Herbivore: Primary consumers that eat only producers.

  3. Omnivore: Consumers that eat both producers and other consumers.

  4. Carnivore: Consumers that eat only other animals.

• Food Chains: A linear representation of the flow of energy from one organism to another within an ecosystem.

• The Biosphere: The global sum of all ecosystems; the thin zone on Earth where life exists, including the atmosphere, lithosphere, and hydrosphere.

Biological Processes and Energy Flux

• Photosynthesis: The process by which producers convert light energy into chemical energy.

  • Formula: $6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$

• Cellular Respiration: The process by which organisms break down glucose to release stored energy.

  • Formula: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy}$

• Species Interactions:

  • Symbiosis: A close relationship between two species.

  • Mutualism: A relationship where both species benefit ($+/+$).

  • Parasitism: A relationship where one species (the parasite) benefits and the other (the host) is harmed ($+/-$).

  • Competition: Occurs when two or more organisms compete for the same limited resources (e.g., food, space).

  • Predation: An interaction where one organism (the predator) hunts and kills another (the prey) for food.

• Carrying Capacity: The maximum population size of a species that a specific environment can sustain indefinitely, given the food, habitat, water, and other available necessities.

• Ecosystem Services: The various benefits that humans freely gain from the natural environment and from properly functioning ecosystems (e.g., pollination, water purification, and climate regulation).

• Energy Sources:

  • Renewable Energy: Energy from sources that are naturally replenished on a human timescale (e.g., Solar, Wind, Hydroelectric, Geothermal).

  • Non-renewable Energy: Energy from sources that will eventually run out or take millions of years to replenish (e.g., Fossil Fuels like Coal, Oil, and Natural Gas; Nuclear energy).