18.2Periodicity
Section · module m68829
What this needs
Learn these first — this section will not make sense without them.
Nothing in the algebra book is a prerequisite for this section.
What this touches
Algebra that turns up here. Not a blocker, but this is where you will see it used.
- Applies2.4Models and Applications
Converting ΔH = −350 kJ mol⁻¹ for CaO + H₂O to kJ per gram, then scaling to a 1-ton batch of slaked lime, chains a divide-by-molar-mass step to a multiply-by-mass-ratio step — the same two-stage unit-rate model as a work-rate or mixture problem, where forgetting to convert the ton to grams before applying the per-gram rate is the standing slip.
- Applies5.9Modeling Using Variation
Recovering the mass of fish that delivers a fatal 0.20 g HgCl₂ dose from a 30 ppm mercury concentration treats ppm as a direct-variation constant (mass Hg = k × mass fish) and solves for the fish mass at a fixed dose — the same y = kx inversion Modeling Using Variation trains, and mixing up which quantity is the constant of variation misplaces a decimal by orders of magnitude.