Nature of Matter: Elements, Compounds, and Mixtures – Formula & Equation Sheet
Essential formulas and equations from Curiosity, tailored for Class 8 in Science.
This one-pager compiles key formulas and equations from the Nature of Matter: Elements, Compounds, and Mixtures chapter of Curiosity. Ideal for exam prep, quick reference, and solving time-bound numerical problems accurately.
Key concepts & formulas
Essential formulas, key terms, and important concepts for quick reference and revision.
Formulas
M = m_1 + m_2
M is the total mass of a mixture, m_1 and m_2 are the masses of individual components. This formula shows how the mass of a mixture is the sum of the masses of its parts.
C = (mass of solute)/(mass of solution) × 100%
C represents the concentration of a solution. A higher concentration means more solute is present in the mixture. Useful in chemistry labs for solution preparation.
d = m/V
d is density, m is mass, and V is volume. Density helps determine whether a substance will float or sink when mixed with another.
P_total = P_1 + P_2 + ... + P_n
P_total is the total pressure of a gas mixture, and P_1, P_2 are the partial pressures of individual gases. Used for calculations involving air and other gas mixtures.
PV = nRT
This is the ideal gas law where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature. It describes the behavior of ideal gases.
NaCl (s) → Na⁺ (aq) + Cl⁻ (aq)
The dissociation of sodium chloride in water. Shows how ionic compounds break into ions in mixtures, which is crucial for understanding solutions.
Lime Water Reaction: Ca(OH)₂ + CO₂ → CaCO₃ (s) + H₂O
This equation demonstrates how lime water reacts with carbon dioxide to form calcium carbonate. Important in experiments dealing with gases.
P_comb = (1/P₁ + 1/P₂ + ... + 1/P_n)⁻¹
This is for calculating the combined resistance in parallel circuits, used in physics to understand mixtures of resistive materials.
T_mixture = (m₁T₁ + m₂T₂)/(m₁ + m₂)
T_mixture is the final temperature of a mixture of two substances with masses m₁ and m₂ at temperatures T₁ and T₂. Useful for calorimetry calculations.
Vol._air = 78% N₂ + 21% O₂ + 1% other gases
Describes the composition of dry air, indicating the ratio of its components. Helps understand mixtures in environmental science.
Equations
Ca(OH)₂ + CO₂ → CaCO₃ + H₂O
This reaction shows how calcium hydroxide reacts with carbon dioxide forming calcium carbonate and water. Key in identifying gas interactions.
Lime Water Reaction: Ca(OH)₂ + CO₂ → CaCO₃ (s) + H₂O
Shows the formation of precipitate in lime water upon reaction with carbon dioxide, useful in testing for CO₂ presence.
Air Quality Index (AQI)
A numerical scale that indicates the cleanliness of the air. Important for environmental science and health awareness.
Mixture Types: Homogeneous vs. Heterogeneous
Defines uniform (homogeneous) mixtures like solutions and non-uniform (heterogeneous) mixtures like salads, critical for understanding matter classifications.
Heat Transfer in Mixtures: Q = mcΔT
Q is the heat absorbed or released, m is mass, c is specific heat capacity, and ΔT is the change in temperature. Fundamental for thermal energy calculations.
F = ma
This equation represents the force acting on an object as the product of its mass (m) and acceleration (a), relevant in physical interactions of matter.
Hydrocarbon Combustion: C_xH_y + O₂ → CO₂ + H₂O
Represents the general reaction of hydrocarbons burning in oxygen, producing carbon dioxide and water, essential in studying combustion in mixtures.
N_2 + 3H_2 ↔ 2NH₃
The Haber process for ammonia synthesis. Important in chemistry, allowing the understanding of gas interactions in mixtures.
Saturated Solution: m_solute/m_solution × 100%
Defines saturation level in solutions, helping identify predominant components in liquid mixtures.
Components of Air: N₂ + O₂ + CO₂ + Water Vapour + Pollutants
Describes the main constituents of air, necessary for understanding environmental science and air quality concerns.
