Québec Sec 4 Applied Science and Technology (057-410) cheat sheet

Matter is organized in levels: atom → molecule → substance → mixture; a pure substance has fixed composition, a mixture does not.

Intensive properties (density, melting point, boiling point, conductivity) do not depend on sample size; extensive properties (mass, volume) do.

Density formula: ρ = m/V, commonly in g/mL or g/cm³; water = 1.00 g/mL at 4 °C, so objects denser than water sink.

Physical change alters state, shape, or size without new substances; chemical change produces new substances with different properties.

Signs of a chemical change: new colour, gas release, precipitate, heat/light emission, odour change - not simply a state change.

Particle model: solids vibrate in fixed positions, liquids slide past each other, gases move freely and fill the container.

Pure substances are elements (one atom type, e.g. O₂) or compounds (fixed ratio of atoms, e.g. H₂O); alloys are mixtures.

Separation techniques: filtration (insoluble solid), decantation, distillation (boiling-point difference), chromatography (solubility), evaporation.

Balanced equation conserves atoms of each element; coefficients multiply the whole formula, subscripts never change during balancing.

Reaction types: synthesis (A+B→AB), decomposition (AB→A+B), combustion (fuel+O₂→CO₂+H₂O), precipitation, acid-base neutralization.

pH scale 0–14: acidic below 7, neutral 7, basic above 7; acids turn blue litmus red, bases turn red litmus blue.

Concentration C = n/V (mol/L) or C = m/V (g/L); dilution obeys C₁V₁ = C₂V₂ because solute amount is unchanged.

Solubility is the maximum solute in a solvent at a given temperature; most solids dissolve better in hot water, gases worse.

Energy: exothermic reactions release heat (temperature rises), endothermic absorb heat (temperature falls); activation energy is the barrier to start.

Law of conservation of energy: energy is neither created nor destroyed, only transformed (chemical, thermal, electrical, radiant, mechanical).

Neutralization: acid + base → salt + water; H⁺ + OH⁻ → H₂O; the resulting pH depends on the relative amounts used.

Living things share organization, metabolism, growth, response to stimuli, reproduction, and adaptation; viruses lack independent metabolism.

Organization levels: cell → tissue → organ → system → organism → population → community → ecosystem → biosphere.

Classification hierarchy: domain, kingdom, phylum, class, order, family, genus, species; the species name is binomial (Genus species).

Prokaryotic cells lack a nucleus and membrane-bound organelles; eukaryotic cells have both (plants, animals, fungi, protists).

Plant cell vs animal cell: plants have a cellulose wall, chloroplasts, and a large central vacuole; animals have centrioles and no wall.

Adaptations are inherited traits improving survival in a habitat: structural (shape), behavioural (migration), physiological (antifreeze).

Natural selection: heritable variation + differential survival and reproduction → traits become more common over generations.

Biodiversity includes genetic, species, and ecosystem diversity; loss of habitat is the leading cause of species decline.

Homeostasis keeps internal conditions stable (temperature, blood glucose, pH, water) through negative feedback loops.

Digestive system breaks polymers into monomers (starch→glucose, protein→amino acids, lipids→fatty acids + glycerol) for absorption.

Circulatory and respiratory systems cooperate: lungs exchange O₂/CO₂, blood transports gases, nutrients, and wastes.

Nervous system: stimulus → receptor → sensory neuron → CNS → motor neuron → effector; reflexes bypass conscious decision.

Mitosis produces two identical diploid cells for growth and repair; meiosis produces four haploid gametes with genetic variation.

Human karyotype: 46 chromosomes = 23 pairs; sex chromosomes XX female, XY male; the father determines the child's sex.

Mendelian genetics: dominant allele masks recessive; monohybrid cross Aa × Aa gives 3:1 phenotype, 1:2:1 genotype.

Punnett squares predict offspring probabilities from parental genotypes; a carrier shows the dominant trait but passes the recessive allele.

Design process: define the problem → constraints and specifications → research → ideas → prototype → test → evaluate → improve.

Constraints are limits (budget, time, materials, safety, regulations); specifications are measurable criteria the solution must satisfy.

Multiview orthographic projection: front, top, and right-side views aligned; hidden features shown dashed, centre lines as long-short dashes.

Scale drawing: scale = drawing dimension / real dimension; 1:50 means 1 cm on paper represents 50 cm in reality.

Dimensions include value and unit; never repeat a dimension, and place dimensions outside the view where possible.

Materials: metals (conductive, ductile), polymers (light, insulating), ceramics (hard, brittle), composites (combine properties).

Material selection criteria: strength, density, hardness, conductivity, corrosion resistance, cost, and recyclability.

Stress = force/area (σ = F/A); a material fails when stress exceeds its yield or ultimate strength.

Mechanical advantage MA = output force / input force = load / effort; a lever trades force for distance.

Lever classes: class 1 fulcrum between load and effort; class 2 load between; class 3 effort between (always MA < 1).

Gears and pulleys: gear ratio = teeth driven / teeth driving; speed ratio is the inverse of the force ratio.

Ohm's law U = RI; power P = UI = RI² = U²/R; electrical energy E = Pt (joules or kWh).

Series circuit: same current everywhere, voltages add, R_total = R₁+R₂+…; one break stops the whole circuit.

Parallel circuit: same voltage across branches, currents add, 1/R_total = 1/R₁+1/R₂+…; one break leaves others working.

System analysis: identify input, process, output, and feedback; a control loop compares output with a set point and corrects it.

Energy efficiency = useful output energy / total input energy × 100%; losses usually appear as heat.

Earth's layers: crust, mantle, outer core (liquid), inner core (solid); tectonic plates move on the asthenosphere.

Plate boundaries: divergent (new crust, ridges), convergent (subduction, mountains, volcanoes), transform (earthquakes, faults).

Rock cycle: igneous (cooled magma), sedimentary (compaction of sediments), metamorphic (heat and pressure); each can transform.

Rock and mineral identification: hardness (Mohs 1–10), cleavage, lustre, colour, streak, acid reaction (calcite fizzes).

Water cycle: evaporation, transpiration, condensation, precipitation, infiltration, runoff; watersheds collect water into one outlet.

Atmosphere composition: about 78% N₂, 21% O₂, 1% argon and other gases, plus variable water vapour and CO₂.

Greenhouse effect: atmospheric gases absorb and re-emit infrared radiation, warming the surface; it is natural but enhanced by CO₂.

Astronomy: Earth rotates in 24 h (day/night), revolves in 365.25 days (seasons from axial tilt, not distance); moon phases cycle ~29.5 days.

Variables: independent (manipulated), dependent (measured), controlled (held constant) to make a fair test.

Hypothesis is a testable prediction stated as cause and effect; a theory is a well-supported explanation, a law describes a pattern.

Validity requires controlling variables; reliability improves with repeated trials and averaging results.

Measurement: report the unit, estimate one digit beyond the smallest scale division, and record uncertainty.

Graph choice: line graph for continuous change, bar graph for categories, pie chart for proportions; label axes with quantity and unit.

Data analysis: mean, median, mode, range; an outlier is checked before being discarded, never silently removed.

Scientific report structure: question, hypothesis, protocol, observations, results, analysis, conclusion, sources of error.

A model simplifies reality to explain or predict; its limits must be stated because it may omit factors or distort scale.