Some Basic Concepts of Chemistry Flashcards

This set of vocabulary flashcards covers historical Indian developments in chemistry, modern definitions of matter, the laws of chemical combination, and quantitative measurement terms including stoichiometry and concentration units.

Chemistry

The branch of science that studies the preparation, properties, structure, and reactions of material substances.

Philosopher’s Stone (Paras)

A substance sought in ancient alchemy believed to be capable of converting baser metals like iron and copper into gold.

Elixir of Life

A legendary substance sought in ancient alchemy believed to grant immortality.

Rasayan Shastra

The name for chemistry in ancient India, which also included terms like Rastantra, Ras Kriya, or Rasvidya.

Faience

A sort of glass used in ornaments by the Harappans.

Nagarjuna

A great Indian scientist and alchemist known for his work Rasratnakar, which deals with the formulation of mercury compounds and metal extraction.

Chakrapani

An Indian scientist credited with discovering mercury sulphide and inventing soap using mustard oil and alkalies.

Acharya Kanda

An Indian philosopher born in 600 BCE and the first proponent of the atomic theory, claiming all substances are made of small indivisible particles called Paramãnu.

Paramãnu

The name given by Acharya Kanda to very small indivisible particles that are eternal, indestructible, spherical, and in motion.

Nanotechnology

The extreme reduction of particle size, described in ancient texts like Charaka Samhita through the use of metal bhasmas.

Matter

Anything which has mass and occupies space.

Solid

A state of matter where particles are held very close together in an orderly fashion with restricted movement, resulting in a definite volume and definite shape.

Liquid

A state of matter where particles are close together but can move around; it has a definite volume but no definite shape.

Gas

A state of matter where particles are far apart and movement is easy and fast; it has neither a definite volume nor a definite shape.

Pure Substance

A substance in which all constituent particles are the same in chemical nature and have a fixed composition.

Mixture

A substance containing particles of two or more pure substances in any ratio, resulting in a variable composition.

Homogeneous Mixture

A mixture where the components are uniformly distributed and the composition is uniform throughout.

Heterogeneous Mixture

A mixture where the composition is not uniform and different components are often visible.

Element

A pure substance consisting of only one type of atoms, which may exist as individual atoms or molecules.

Compound

A substance obtained when two or more atoms of different elements combine together in a definite ratio.

Physical Properties

Characteristics such as colour, odour, melting point, and density that can be measured or observed without changing the identity of the substance.

Chemical Properties

Characteristics like composition, combustibility, or reactivity that require a chemical change to be measured or observed.

SI System

The International System of Units (Le Systeme International d’Unités) established by the 11th General Conference on Weights and Measures.

Mass

The amount of matter present in a substance; it is constant regardless of location.

Weight

The force exerted by gravity on an object; it may vary from one place to another.

Density

The amount of mass per unit volume, calculated as $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$.

Scientific Notation

An exponential notation in the form $N \times 10^n$, where $n$ is an exponent and $N$ is a number between 1.000… and 9.999….

Significant Figures

Meaningful digits in a measurement which are known with certainty plus one digit that is estimated.

Precision

The closeness of various measurements for the same quantity.

Accuracy

The agreement of a particular value to the true value of the result.

Dimensional Analysis

A method used to convert units from one system to another, also known as the factor label method or unit factor method.

Law of Conservation of Mass

A law put forth by Antoine Lavoisier stating that matter can neither be created nor destroyed in physical and chemical changes.

Law of Definite Proportions

A law stated by Joseph Proust which says a given compound always contains exactly the same proportion of elements by weight.

Law of Multiple Proportions

A law proposed by Dalton stating that if two elements form more than one compound, the masses of one element that combine with a fixed mass of the other are in a ratio of small whole numbers.

Gay Lussac’s Law of Gaseous Volumes

States that when gases combine or are produced in a chemical reaction, they do so in a simple ratio by volume at constant temperature and pressure.

Avogadro’s Law

Proposes that equal volumes of all gases at the same temperature and pressure should contain an equal number of molecules.

Atomic Mass Unit (amu)

A mass exactly equal to one-twelfth of the mass of one carbon-12 atom, equivalent to $1.66056 \times 10^{-24}\,g$.

Unified Mass (u)

The modern replacement for the atomic mass unit (amu).

Molecular Mass

The sum of atomic masses of the elements present in a molecule.

Formula Mass

The sum of atomic masses used for substances like sodium chloride which do not contain discrete molecules.

Mole (mol)

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

Avogadro Constant ($N_A$)

The fixed numerical value of $6.02214076 \times 10^{23}\,mol^{-1}$.

Molar Mass

The mass of one mole of a substance in grams.

Empirical Formula

The simplest whole number ratio of various atoms present in a compound.

Molecular Formula

The formula showing the exact number of different types of atoms present in a molecule of a compound.

Stoichiometry

The calculation of masses (and sometimes volumes) of reactants and products involved in a chemical reaction.

Limiting Reagent

The reactant that is present in the least amount and gets consumed first, limiting the amount of product formed.

Mass Per Cent

The ratio of the mass of a solute to the total mass of the solution multiplied by 100.

Mole Fraction

The ratio of the number of moles of a particular component to the total number of moles of the solution.

Molarity (M)

The number of moles of the solute in 1 litre of the solution.

Molality (m)

The number of moles of solute present in $1\,kg$ of solvent.