Ontario Grade 12 SCH4C Chemistry (Grade 12, College Preparation)
Chapters: 6
1. A. Scientific Investigation Skills and Career Exploration
A1 Scientific Investigation Skills · A2 Career Exploration
- The Scientific Method – The scientific method is the careful way scientists find out how the world works. Observe something, ask a testable question, make a hypothesis (a clear, testable guess), test it with a fair experiment (change one variable, measure one, keep the rest the same), repeat and record data, analyse it, draw a conclusion and share it so others can check. Results that fail the test are useful too: they send you back to a new hypothesis.
2. B. Matter and Qualitative Analysis
B1 Relating Science to Technology, Society, and the Environment · B2 Developing Skills of Investigation and Communication · B3 Understanding Basic Concepts
- Tests for Ions: Flame Tests, Hydroxide Precipitates, Anion Tests and Flame Emission Spectroscopy – An ionic compound is made of a positive metal ion and a negative ion. Each can be found with its own test. Flame tests show metal ions by colour: lithium crimson, sodium yellow, potassium lilac, calcium orange-red, copper green. Sodium hydroxide gives coloured hydroxide precipitates: Cu²⁺ blue, Fe²⁺ green, Fe³⁺ brown, Al³⁺, Ca²⁺ and Mg²⁺ white (only Al(OH)₃ dissolves in excess). Carbonates fizz with acid and the gas turns limewater milky. Halides with acidified silver nitrate: chloride white, bromide cream, iodide yellow. Sulfates with acidified barium chloride: white precipitate. Instruments such as flame emission spectroscopy are faster, more sensitive and can measure amounts.
3. C. Organic Chemistry
C1 Relating Science to Technology, Society, and the Environment · C2 Developing Skills of Investigation and Communication · C3 Understanding Basic Concepts
- Organic Compounds: Structure, Formulae and Classification – Organic chemistry is the chemistry of carbon compounds. A carbon atom has 4 outer electrons, so it always makes 4 bonds. This is called tetravalence. With 4 single bonds the carbon is sp³ and its bonds point to the corners of a tetrahedron (109.5°). With one double bond it is sp² and flat (120°). With a triple bond it is sp and straight (180°). We can draw the same molecule in several ways: complete, condensed, bond-line and 3D wedge-dash. Finally we sort organic compounds into open-chain and ring compounds, and into families by their functional group. Members of one family form a homologous series, where each member differs by one CH₂.
4. D. Electrochemistry
D1 Relating Science to Technology, Society, and the Environment · D2 Developing Skills of Investigation and Communication · D3 Understanding Basic Concepts
- Redox Reactions and Electrode Processes – If we keep the oxidation half and the reduction half in separate beakers and join them with a wire and a salt bridge, the electrons travel through the wire. This makes a cell. Each metal in its ion solution is an electrode with its own potential. The hydrogen electrode is set at 0.00 V. Listing electrodes by standard potential gives the electrochemical series, and E°cell = E°(cathode) − E°(anode).
5. E. Chemical Calculations
E1 Relating Science to Technology, Society, and the Environment · E2 Developing Skills of Investigation and Communication · E3 Understanding Basic Concepts
- Mole Concept, Molar Mass and Chemical Formulas – Atoms are far too small to count one by one, so chemists count them by weighing. Atomic masses are given in u, where 1 u is one-twelfth the mass of a carbon-12 atom. One mole is 6.022 × 10²³ particles, and its mass in grams equals the formula mass in u. With moles we can find the percentage of each element in a compound, and work back from percentages to the empirical and molecular formulas.
6. F. Chemistry in the Environment
F1 Relating Science to Technology, Society, and the Environment · F2 Developing Skills of Investigation and Communication · F3 Understanding Basic Concepts
- Environmental Chemistry – Environmental chemistry studies the chemicals in air, water and soil, where they come from and what they do. Dry air is about 78% nitrogen, 21% oxygen, 0.9% argon and 0.04% carbon dioxide. Burning fuels adds pollutants such as SO₂, NOₓ, CO and particulates. SO₂ and NO₂ form acids in rain (pH below 5.6). We measure pollution with quantitative tests such as titration, compare the results with standards, and use laws and cleaner technology to reduce harm.