Physics Chapter 2

Grade 9 Science Final Exam Overview

• The exam is worth 10% of the final mark.
• Permitted materials: Pens, pencils, erasers, calculator, and a periodic table (provided).
• No sharing of materials.

Mark/Time Breakdown

• Knowledge (30 multiple choice): 28 marks, 30 minutes
• Thinking (short answer): 23 marks, 25 minutes
• Communication (short answer): 10 marks, 10 minutes
• Application (making connections): 14 marks, 15 minutes
• Review: 10 minutes
• Total: 75 Marks, 90 minutes

Chemistry 5.1 Particle Theory of Matter

• Basic Idea: Matter is made up of tiny particles (atoms or molecules) that are constantly in motion.
• Key Points:
  • Matter is made of particles too small to see.
  • Particles constantly move (vibrate, slide, or freely).
  • Particles have spaces between them.
  • Particles are attracted to each other (strength varies in solids, liquids, and gases).
  • Temperature affects particle motion (warmer = faster, cooler = slower).
• States of Matter:
  • Solids: Tightly packed particles, fixed shape and volume, vibrate in place.
  • Liquids: Close together but can move past each other, fixed volume, changeable shape.
  • Gases: Far apart, move freely, no fixed shape or volume.
• Changes of State: Melting, freezing, evaporation, condensation, sublimation.
• Important Factors:
  • Temperature affects particle speeds.
  • Pressure also affects gas particles.

5.2 Physical Properties

• Definition: Characteristics that can be observed or measured without changing the substance.
• Common Properties: Color, density, melting point, boiling point, state of matter, solubility, hardness, conductivity, magnetism, viscosity, transparency.
• Importance: Identifying substances by characteristics.

5.3 Chemical Properties

• Definition: How a substance reacts with other substances.
• Examples: Reactivity with water, reactivity with oxygen, flammability, acidity/basicity, toxicity, corrosion resistance.
• Observation: Observed only during a chemical reaction.

Qualitative vs. Quantitative Properties

• Qualitative Properties: Describe qualities or characteristics (e.g., color, texture).
• Quantitative Properties: Describe quantities or measurable properties (e.g., mass, temperature).

5.6 Characteristic Physical Properties (Density Calculations)

• Density: Mass contained in a given volume.
• Formula: Density = mass/volume.
• Units: Grams per cubic centimeter (g/cm³) or kilograms per cubic meter (kg/m³).

GRASP Method for Solving Problems

• Given (what information is provided).
• Required (what information needs to be found).
• Assumptions (needed for accuracy).
• Solution (steps using formulas/calculations).
• Prove (check calculation validity; correct units, reasonableness).

Unique Properties of Water

• High Specific Heat: Needs a large amount of heat to change temperature.
• High Heat of Vaporization: Absorbs a large amount of heat before evaporating.
• Density Anomaly: Most dense at 4°C (ice floats).
• Cohesion and Adhesion: Water molecules cling to each other and other materials (properties vital for many biological processes).

6.1 Elements, Counting Atoms

• Elements: Pure substances composed of one type of atom.
• Periodic Table: Organizes known elements by atomic number (number of protons).
• Atoms: Smallest unit of an element.
• Atomic Number: Number of protons in an atom's nucleus.
• Atomic Mass: Sum of protons and neutrons.
• Molecules: Two or more atoms bonded together.

6. Metals vs Nonmetals

• Metals: Good conductors, usually solid, shiny, malleable and ductile, usually on the left side of the periodic table.
• Nonmetals: Poor conductors, various states, often brittle, usually on the right side of the periodic table).

6.4 Patterns in the Periodic Table

• Mendeleev: Arranged elements by increasing atomic mass, noticing patterns in properties.
• Modern Table: Arranged by increasing atomic number, columns (groups) have similar properties, rows (periods) show a pattern in how properties change.
• Predicting Properties: Knowing a group or period lets you predict a substance's reactivity, atomic size, ionization energy, and electronegativity.
• Reactivity: Ability to combine with other elements.

6.6 Theories of the Atom (Rutherford, Bohr, and particles)

• Dalton (1803): Atoms are indivisible, all of a given element are identical, reactions involve atom rearrangement.
• Rutherford (1911): Nucleus, mostly empty space, electrons orbit nucleus.
• Bohr (1913): Electrons exist in specific energy shells (orbits), and only specific energy levels are allowed, electrons do not constantly emit radiation as they orbit the nucleus, jumping between orbitals involves absorbing or releasing energy.
• Subatomic Particles: Protons, electrons, neutrons.

6.7 Bohr Diagrams

• Diagrams that show the arrangement of electrons in energy levels around the nucleus of an atom.

12.3 Electrical Energy

• Definition: Energy stored in and used by electric charges.
• Symbol: E or W (Work).
• Unit: Joule (J).

12.4 AC/DC Definitions

• AC (Alternating Current): Current direction alternates periodically.
• DC (Direct Current): Current flows in one constant direction.

12.5 Generating Electrical Energy

• Nuclear Power: Fission of atoms, electricity generated from the heat.
• Hydroelectric Power: Water driven turbines.
• Solar Power: Photovoltaic cells convert sunlight to electricity.
• Wind Power: Turbines convert wind energy to electricity.
• Fossil Fuels (Coal, Natural Gas, Oil): Burning fuels creates heat, steam, which powers turbines.

13.1 Series Circuits

• Components are connected end-to-end.
• Same current travels through all components.
• Total voltage equals the sum of voltages across each component.
• Total resistance equals the sum of individual resistances.

13.2 Parallel Circuits

• Components are connected across each other.
• Same voltage across each component.
• Total current equals the sum of currents through each branch.
• Reciprocal relation of the total resistance is the sum of the reciprocals of individual resistances.

13.3 Symbols & Units

• Current (I) - measured in amperes (A).
• Voltage (V) - measured in volts (V).

13.7 Electrical Resistance

• Definition: Opposition to current flow.
• Symbol: R.
• Unit: Ohm (Ω).
• Factors Affecting Resistance: Material, length, cross-sectional area, temperature. (Copper has low resistivity compared to other materials). Resistance is directly proportional to the length of the conductor. Resistance is inversely proportional to its cross- sectional area.

13.9 Ohm's Law Calculations

• Formula: V = I × R (Voltage equals Current times Resistance)
• Rearranged Formulas: I = V/R, R = V/I