Some Basic Concepts of Chemistry

Flashcards for reviewing basic chemistry concepts, including the nature of chemistry, matter classification, measurement units, laws of chemical combination, atomic theory, and stoichiometry.

Chemistry

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

Rasayan Shastra

Ancient Indian term for chemistry, encompassing metallurgy, medicine, cosmetics, and more.

Matter

Anything that has mass and occupies space.

States of Matter

Solid, liquid, and gas.

Pure Substance

A substance with uniform chemical composition throughout (elements and compounds).

Elements

Substances composed of only one type of atom.

Compounds

Substances formed when two or more different elements combine in a fixed ratio.

Mixture

Combination of two or more pure substances in any ratio.

Physical Properties

Properties that can be measured or observed without changing the identity or composition of the substance.

Examples of Physical properties

Are color, odor, melting point, boiling point and density.

Chemical Properties

Properties related to the chemical changes or reactions that a substance undergoes.

International System of Units (SI)

The system of units established in 1960 by the General Conference on Weights and Measures.

Mass

Amount of matter present in a substance.

Weight

Force exerted by gravity on an object.

Volume

Amount of space occupied by a substance.

Density

Amount of mass per unit volume.

Scientific Notation

A way of writing numbers that are too big or too small to be conveniently written in decimal form.

Significant Figures

Meaningful digits in a measured or calculated quantity.

Precision

Closeness of various measurements for the same quantity.

Accuracy

Agreement of a particular value to the true value of the result.

Dimensional Analysis

Method used to convert units from one system to another.

Law of Conservation of Mass

In all physical and chemical changes, there is no net change in mass during the process.

Law of Definite Proportions

A given compound always contains exactly the same proportion of elements by weight.

Law of Multiple Proportions

If two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in the ratio of small whole numbers.

Gay-Lussac's Law of Gaseous Volumes

When gases combine or are produced in a chemical reaction, they do so in a simple ratio by volume, provided all gases are at the same temperature and pressure.

Avogadro's Law

Equal volumes of all gases at the same temperature and pressure should contain equal numbers of molecules.

Dalton's Atomic Theory

Matter consists of indivisible atoms; all atoms of a given element have identical properties including mass.

Atomic Mass

Mass of an atom relative to carbon-12 standard.

Average Atomic Mass

Average of the atomic masses of all isotopes of an element, considering their natural abundance.

Molecular Mass

Sum of atomic masses of the elements present in a molecule.

Formula Mass

Mass of the ionic compound.

Mole

The SI unit of amount of substance and contains exactly 6.02214076 ×1023 elementary entities.

Avogadro Constant

Avogadro's Number = 6.022 x 10^23

Molar Mass

The mass of one mole of a substance in grams.

Percentage Composition

Mass of that element in the compound divided by the molar mass of the compound, multiplied by 100.

Empirical Formula

Represents the simplest whole number ratio of atoms in a compound.

Molecular Formula

Shows the exact number of different types of atoms in a molecule of a compound.

Stoichiometry

Deals with the calculation of masses of reactants and products in a chemical reaction.

Limiting Reagent

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

Molarity

Number of moles of the solute in 1 liter of the solution.

Mole Fraction

Ratio of the number of moles of a particular component to the total number of moles of the solution.

Molality

Number of moles of solute present in 1 kg of solvent.