Unit 1: Some Basic Concepts of Chemistry

Vocabulary flashcards generated from lecture notes covering key terms, historical context, laws of chemical combination, measurement units, atomic masses, stoichiometry, and solution concentration expressions in Chemistry.

Science

A continuing human effort to systematize knowledge for describing and understanding nature.

Chemistry

The branch of science that studies the preparation, properties, structure, and reactions of material substances, often referred to as the science of molecules and their transformations.

Philosopher's stone (Paras)

A substance historically believed by alchemists to convert base metals like iron and copper into gold.

Elixir of life

A substance historically believed to grant immortality.

Rasayan Shastra

The ancient Indian name for chemistry, encompassing metallurgy, medicine, and the manufacture of cosmetics, glass, and dyes.

Faience

A type of glass manufactured by the ancient Harappans for use in ornaments.

Rasratnakar

A text written by the Indian scientist Nagarjuna dealing with mercury compounds and methods for extracting metals such as gold, silver, tin, and copper.

Brihat Samhita

A 6th century CE encyclopaedia by Varahmihir providing recipes for cosmetics, perfumes, and glutinous materials for roofs and walls.

Paramanu

Indivisible, eternal, spherical, and suprasensible building blocks of matter conceptualized by Acharya Kanda around 600 BCE.

Vaiseshika Sutras

The ancient text authored by Acharya Kanda proposing the theory of Paramanu (atomic theory).

Matter

Anything that possesses mass and occupies space.

Solid State

A state of matter where constituent particles are held close together in an orderly arrangement with limited freedom of movement, giving it a definite volume and shape.

Liquid State

A state of matter where particles are close but can move around, resulting in a definite volume but no definite shape.

Gas State

A state of matter in which particles are far apart and move rapidly, giving it neither a definite volume nor a definite shape.

Pure Substance

A form of matter in which all constituent particles are identical in chemical nature with a fixed composition.

Mixture

A combination of two or more pure substances present in variable ratios, which can be separated into its components by physical methods.

Homogeneous Mixture

A mixture whose components are completely mixed and uniformly distributed throughout its mass.

Heterogeneous Mixture

A mixture with a non-uniform composition where constituent components remain separate and distinguishable.

Element

A pure substance whose constituent particles consist of only one type of atom.

Compound

A pure substance formed when two or more atoms of different elements combine in a fixed, definite ratio.

Physical Properties

Characteristics of a substance that can be measured or observed without altering its chemical identity or composition.

Chemical Properties

Characteristics of a substance whose measurement or observation requires a chemical reaction or change to occur.

International System of Units (SI)

A standardized universal measurement system established in 1960 by the 11th General Conference on Weights and Measures (CGPM), based on seven fundamental base units.

Mass

The constant amount of matter contained within a physical substance.

Weight

The force exerted on an object by gravity, which varies based on location.

Density

The ratio of mass per unit volume of a substance, represented by the SI unit $\text{kg}\text{m}^{-3}$.

Kelvin (K)

The SI base unit for thermodynamic temperature.

Scientific Notation

A method of expressing numbers in the form $N \times 10^n$, where $N$ is a digit term between 1.000… and 9.999… and $n$ is an exponent.

Significant Figures

Total number of meaningful digits in a measured quantity known with certainty plus one uncertain or estimated digit.

Precision

The degree of closeness among several measured values obtained for the same quantity.

Accuracy

The closeness of a single measured value to the true value of the quantity being measured.

Dimensional Analysis

A conversion method that uses unit factors (ratios equal to 1) to convert measurements from one unit system to another.

Law of Conservation of Mass

A chemical law formulated by Antoine Lavoisier in 1789 stating that matter can neither be created nor destroyed in any physical or chemical change.

Law of Definite Proportions

A chemical law stated by Joseph Proust showing that a given compound always contains exactly the same ratio of constituent elements by mass.

Law of Multiple Proportions

A law proposed by John Dalton in 1803 stating that when two elements form more than one compound, the masses of one element that combine with a fixed mass of the second element are in small whole-number ratios.

Gay-Lussac's Law of Gaseous Volumes

A law stated in 1808 specifying that when gases combine or are produced in a chemical reaction, they do so in a simple volume ratio provided temperature and pressure remain constant.

Avogadro's Law

A principle proposed in 1811 stating that equal volumes of all gases under identical temperature and pressure conditions contain an equal number of molecules.

Atomic Mass Unit (amu)

A unit of mass defined as exactly one-twelfth of the mass of a single carbon-12 atom, equal to $1.66056 \times 10^{-24}\text{g}$.

Average Atomic Mass

The weighted average mass of all naturally occurring isotopes of an element calculated using their fractional abundances.

Molecular Mass

The sum of the individual atomic masses of all atoms present in a single molecule.

Formula Mass

The sum of the atomic masses of all atoms present in the formula unit of a non-molecular or ionic compound.

Mole (mol)

The SI base unit for the amount of substance containing exactly $6.02214076 \times 10^{23}$ elementary entities.

Avogadro Constant (N_A)

The exact numerical value $6.02214076 \times 10^{23}\text{mol}^{-1}$, representing the number of entities in one mole of any substance.

Molar Mass

The mass of one mole of a substance expressed in grams per mole ($\text{g}\text{mol}^{-1}$).

Mass Per Cent (w/w %)

The percentage mass of a solute or element, calculated as $\frac{\text{Mass of component}}{\text{Total mass}} \times 100$.

Empirical Formula

The simplest whole-number ratio of the different atoms present in a chemical compound.

Molecular Formula

The formula representing the exact total number of each atom type contained within a molecule of a compound.

Stoichiometry

The quantitative calculations of relative masses and volumes of reactants and products involved in a chemical reaction.

Limiting Reagent

The reactant in a chemical reaction that is completely consumed first and determines the maximum amount of product formed.

Mole Fraction

The ratio of the number of moles of one specific component to the total number of moles of all components in a solution.

Molarity (M)

A temperature-dependent measure of solution concentration defined as the number of moles of solute per litre of solution.

Molality (m)

A temperature-independent concentration measure defined as the number of moles of solute dissolved in $1\text{kg}$ of solvent.