General Sciences - Modality Subjects in Aragón's PAU/EBAU
This domain covers the Sciences-track modality papers in Aragón's PAU/EBAU: Matemáticas II, Física, Química, Biología, Geología and Dibujo Técnico II. Each paper lasts 90 minutes and offers two options (A/B); you answer one. Questions are contextualized and test scientific competence: model the situation, select the appropriate law, calculate with units, and justify the result. Pure recall is rarely enough.
What the papers reward
- A visible chain: data → principle → equation → substitution → result with units.
- Reading graphs and tables: state what the slope, intercept or plateau means physically.
- Experimental reasoning: control variables, uncertainty, significant figures.
- Concise written justification in Spanish, naming the law or principle used.
Core rules by area
- Matemáticas II: domains, limits, derivatives (optimization, tangents), integrals (areas), matrices, probability. Check domain and boundary conditions.
- Física: free-body diagrams, conservation laws, fields, waves, circuits. Fix a sign convention before substituting.
- Química: stoichiometry, equilibrium (Kc/Kp, Le Chatelier), acid–base, redox, organic functional groups.
- Biología: genetics (pedigrees, conditional probability), metabolism, molecular biology. Use allele notation consistently.
- Geología: stratigraphy, structures, maps; interpret sequences and relative ages.
- Dibujo Técnico II: standardized projections, tolerances, dimensioning; construction accuracy is marked.
Worked example
A 0.50 kg block slides down a 30° incline with μ = 0.20. Find its acceleration. Forces along the slope: mg sin30° − f = ma; normal N = mg cos30°, so f = μmg cos30°. Hence a = g(sin30° − μ cos30°) = 9.8(0.500 − 0.20 × 0.866) = 9.8 × 0.327 ≈ 3.2 m s⁻². The block accelerates down the slope; the mass cancels, which is the check.
Traps that cost marks
- Converting cm→m or g→kg late, or omitting units in the final answer.
- Rounding intermediate values; keep 3–4 significant figures until the end.
- Using equilibrium concentrations in Q, or confusing Kc with Kp.
- Genetics: forgetting that 'probability an affected child is born' may need P(parent carrier) × P(transmission).
- Writing only the numerical result without naming the principle or interpreting it.