This chapter introduces basic concepts of chemistry, including the study of matter, its properties, and its transformations. Understanding these concepts is crucial for students as they lay the foundation for further studies in chemistry.
Some Basic Concepts of Chemistry – Formula & Equation Sheet
Essential formulas and equations from Chemistry Part - I, tailored for Class 11 in Chemistry.
This one-pager compiles key formulas and equations from the Some Basic Concepts of Chemistry chapter of Chemistry Part - I. 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
Molarity (M) = n (moles of solute) / V (liters of solution)
Molarity is a measure of concentration. n represents the number of moles of solute, and V is the volume of the solution in liters.
Molality (m) = n (moles of solute) / m (kg of solvent)
Molality indicates the concentration of a solute in a solvent. n is the number of moles of the solute, and m is the mass of the solvent in kilograms.
Mass Percent = (mass of solute / mass of solution) × 100
This formula calculates the percentage by mass of a component in a solution.
Density (d) = mass (g) / volume (mL or cm³)
Density tells how much mass is contained in a unit volume of a substance.
Ideal Gas Law: PV = nRT
P is pressure (atm), V is volume (L), n is moles of gas, R is the ideal gas constant (0.0821 L·atm/(K·mol)), and T is temperature (K). Describes the behavior of ideal gases.
PV = nRT for Real Gases
This formula applies to gases under ideal conditions and can be adjusted for non-ideal gases using Van der Waals equation.
PV/nT = R (Ideal Gas Equation)
This rearrangement provides a relation between pressure, volume, and temperature of an ideal gas.
Percentage Composition = (mass of element in compound / molar mass of compound) × 100
Used to find the percent by mass of an element in a compound.
Empirical Formula: n(Empirical Formula Mass) = Molar Mass
The empirical formula gives the simplest ratio of elements in a compound, while the molar mass allows calculation to determine the molecular formula.
Avogadro's Law: V₁ / n₁ = V₂ / n₂
States that equal volumes of gases at the same temperature and pressure contain the same number of molecules.
Equations
Combustion of Methane: CH₄ + 2 O₂ → CO₂ + 2 H₂O
This equation demonstrates the reaction of methane with oxygen, producing carbon dioxide and water.
Law of Conservation of Mass: m_reactants = m_products
States that the mass of reactants in a chemical reaction equals the mass of products formed.
Law of Definite Proportions: Mass % = constant
A given compound always contains the same proportion of elements by mass, irrespective of its source.
Law of Multiple Proportions: mass ratio of elements in compounds = small whole numbers
When two elements form more than one compound, the ratios of the masses of one element that combines with a fixed mass of the other element can be expressed in small whole numbers.
Volume Ratios (Gaseous Reactions): V₁ / V₂ = small whole numbers
In reactions involving gases, the volumes of gaseous reactants and products can also be expressed in simple integer ratios.
1 mole = 6.022 × 10²³ particles (Avogadro's number)
Defines the number of units (atoms, molecules, etc.) in one mole of a substance.
Total Pressure (P) = Pressure₁ + Pressure₂ + … + Pressure_n
For mixtures of gases, the total pressure exerted is equal to the sum of the partial pressures of individual gases.
n = m / M, where n = moles, m = mass (g), M = molar mass (g/mol)
The formula used to calculate the number of moles from mass and molar mass.
pH = -log[H⁺]
This equation relates the concentration of hydrogen ions in solution to pH, indicating the acidity or basicity of the solution.
Ka = [H⁺][A⁻]/[HA] (Acid dissociation)
This equation is used to calculate the acid dissociation constant (Ka) from the concentrations of the species in solution.
This chapter introduces the structure of atoms, focusing on sub-atomic particles, atomic models, and quantum mechanics, which are fundamental to understanding chemistry.
Start chapterThis chapter discusses the system of classifying elements based on their properties and the periodicity observed in these properties. It is vital for understanding chemical behavior and the organization of the periodic table.
Start chapterThis chapter explains the fundamental concepts of chemical bonding and molecular structure, focusing on theories that describe how atoms combine to form molecules, which is essential for understanding chemical reactions.
Start chapterThis chapter introduces thermodynamics, the study of energy changes in chemical reactions and processes. Understanding thermodynamics is essential for predicting how and why reactions occur.
Start chapterThis chapter covers the principles of chemical equilibrium, including its significance in biological and environmental processes. It emphasizes understanding dynamic equilibrium, the equilibrium constant, and the factors affecting equilibrium states.
Start chapter
