Natural Sciences (Physics, Chemistry, Biology, Geography)
Natural sciences integrates physics, chemistry, biology, and geography. The attestation checks core laws and definitions, the ability to read graphs and maps, and quantitative problem solving with correct units.
Core concepts
- Physics: speed and acceleration; Newton’s laws; Ohm’s law I=U/R; series and parallel circuits.
- Chemistry: periodic table groups and periods; valency; balancing equations; amount of substance n=m/M.
- Biology: cell structure; photosynthesis and respiration; heredity and variation.
- Geography: Kazakhstan’s climate, rivers, natural zones, and map scale.
Worked example
How many grams of oxygen react with 4 g of hydrogen? 2H₂+O₂→2H₂O. n(H₂)=4/2=2 mol. The equation needs 1 mol O₂ per 2 mol H₂, so n(O₂)=1 mol. M(O₂)=32 g/mol, therefore m=32 g. Reasoning: convert mass to moles, use the balanced ratio, convert back to mass.
Traps
- Using 16 g/mol for O₂ instead of 32 g/mol.
- Balancing equations by changing subscripts rather than coefficients.
- Confusing speed (scalar) with velocity (vector).
- Reversing photosynthesis and respiration.
- Reading map scale as a ratio without converting units.