Chemistry and Biology Equations and Concepts

• Bio-magnification is calculated as actual size divided by image size.
• Photosynthesis equation: 6CO2 + 6H2O → C6H12O6 + 6O2
• Aerobic respiration equation: C6H12O6 + 6O2 → 6CO2 + 6H2O
• Anaerobic respiration equation: glucose → lactic acid

Chem

• Concentration can be measured in grams per cubic decimeter (g/dm^3).
• Avogadro's constant is 6.02 x 10^23.
• Concentration can also be measured in moles per cubic decimeter (mol/dm^3).
• Volume is often measured in cubic decimeters (dm^3).
• To convert cubic centimeters (cm^3) to cubic decimeters (dm^3), divide by 1000.
• Alkanes have the general formula CnH2n+2.
• Alkenes have the general formula CnH2n.
• Alcohols have the general formula CnH2n+1OH.

Extraction of Iron from Hematite

• Occurs in a blast furnace.
• Carbon (coke) burns to provide heat and produce carbon dioxide: C + O2 → CO2
• Carbon dioxide is reduced to carbon monoxide: C + CO2 → 2CO
• Iron(III) oxide is reduced by carbon monoxide: Fe2O3 + 3CO → 2Fe + 3CO2
• Calcium carbonate/limestone thermally decomposes to produce calcium oxide: CaCO3 → CaO + CO2
• Slag forms from the reaction of calcium oxide and silicon dioxide: CaO + SiO2 → CaSiO3
• Air composition: approximately 78% nitrogen (N2), 21% oxygen (O2), with the remainder being a mixture of noble gases and carbon dioxide (CO2).
• Catalytic converters remove oxides of nitrogen: 2CO + 2NO → 2CO2 + N2

Chromatography

• The retardation factor (Rf) is calculated as the distance travelled by the substance divided by the distance travelled by the solvent.
• The Rf value represents the ratio of the solute's distance travelled to the solvent's distance travelled in chromatography.

Physics

• Speed is calculated as distance divided by time.
• Acceleration is calculated as the change in velocity divided by the change in time.
• Earth's gravitational force is approximately 9.8 m/s^2.
• Gravitational field strength (g) is weight (W) divided by mass (m): g = W/m
• Weight (W) is measured in Newtons (N), and mass (m) is measured in kilograms (kg).
• Density is calculated as mass divided by volume.
• Spring constant is calculated as force divided by extension.
• The moment of a force is calculated as force multiplied by the perpendicular distance from the pivot.
• Kinetic energy (Ek) is calculated as 1/2mv^2.
• Change in gravitational potential energy (ΔEp) is calculated as mgΔh.
• Efficiency is calculated as (useful energy output / total energy input) × 100%.
• Work done is equal to the energy transferred.
• Power is calculated as work divided by time.
• Pressure (in pascals) is calculated as force divided by area.
• Wave speed is calculated as frequency multiplied by wavelength (λ).
• Refractive index (n) is calculated as sin(i) / sin(r), where 'i' is the angle of incidence and 'r' is the angle of refraction.
• The speed of light/electromagnetic waves in a vacuum is 3.0 × 10^8 m/s.
• The range of audible frequencies for humans is 20Hz - 20kHz.
• Current (I) is calculated as charge (Q) divided by time (t): I = Q/t
• Voltage (V) is calculated as resistance (R) multiplied by current (I): V = R x I
• Power (P) is calculated as current (I) multiplied by voltage (V): P = IV
• Power (P) is calculated as current (I) squared multiplied by resistance (R): P = I^2R
• Electrical energy (E) is calculated as power (P) multiplied by time (t): E = IVt
• Orbital speed (v) is calculated as circumference (2πr) divided by orbital period (T): v = 2πr / T