সুখবর হচ্ছে বাংলাদেশই তৈরি হচ্ছে করোনাভাইরাসের প্রতিষেধক অ্যাভিগান

absolute alcohol - common name for high purity ethanol or ethyl alcohol.

absolute error - expression of the uncertainty or inaccuracy of a measurement.

absolute temperature - temperature measured using the Kelvin scale.

absolute uncertainty - the uncertainty of a scientific measurement, given in the same units as the measurement.

absolute zero - the lowest possible state at which matter can exist, 0 K or -273.15°C.

absorbance - measure of the amount of light absorbed by a sample.

absorption - process by which atoms, ions, or molecules enter a bulk phase.

absorption spectroscopy - technique used to determine concentration and structure of a sample based on which wavelengths of liquid are absorbed.

absorption spectrum - graph of amount of absorption as a function of wavelength.

absorptivity - absorption cross section of extinction coefficient, which is the absorbance of a solution per unit path length and concentration.

accuracy - the closeness of a measurement to a true or accepted value.

acid - a chemical species that accepts electrons or donate protons or hydrogen ions.

acid anhydride - a nonmetal oxide that reacts with water to form an acidic solution.

acid-base indicator - a weak acid or weak base that changes color when the concentration of hydrogen or hydroxide ions changes in an aqueous solution.

acid-base titration - a procedure to find the concentration of an acid or base by reacting a known concentration with the unknown until the equivalence point is reached.

acid dissociation constant - Ka - a quantitative measure of how strong an acid is.

acidic solution - an aqueous solution with a pH less than 7.0.

actinides - Usually, the actinides are considered to be elements 90 (thorium) through 103 (lawrencium). Otherwise, the actinides are defined according to their common properties.

actinium - the name for the element with atomic number 89 and is represented by the symbol Ac. It is a member of the actinide group.

activated complex - an intermediate state at the maximum energy point on the reaction path that occurs as reactants are being converted into product in a chemical reaction.

activation energy - Ea - the minimum amount of energy needed for a chemical reaction to occur.

active transport - the movement of molecules or ions from a region of lower concentration to higher concentration; requires energy

activity series - list of metals ranked in order of decreasing activity, used to predict which metals displace others in aqueous solutions.

actual yield - the quantity of product experimentally obtained from a chemical reaction.

acute health effect - the effect caused by initial exposure to a chemical.

acyl group - a functional group with the formula RCO- where R is bound to carbon via a single bond.

adsorption - the adhesion of a chemical species onto a surface

adulterant - a chemical that acts as a contaminant in the context of another substance's purity.

aether - a medium believed to carry light waves in the 18th and 19th century.

air - the mixture of gases that make up the Earth's atmosphere, consisting mainly of nitrogen, with oxygen, water vapor, argon, and carbon dioxide.

alchemy -Several definitions of alchemy exist. Originally, alchemy was an ancient tradition of sacred chemistry used to discern the spiritual and temporal nature of reality, its structure, laws, and functions.

alcohol - a substance that contains an -OH group attached to a hydrocarbon.

aliphatic amino acid - amino acid that has an aliphatic side chain.

aliphatic compound - an organic compound containing carbon and hydrogen joined into straight chains, branches chains, or non-aromatic rings.

aliphatic hydrocarbon - a hydrocarbon containing carbon and hydrogen joined into straight chains, branches chains, or non-aromatic rings.

alkali metal - any element found in group IA (first column) of the periodic table.

alkaline - an aqueous solution with a pH greater than 7.

alkalinity - a quantitative measure of a solution's ability to neutralize an acid.

alkene - a hydrocarbon containing a double carbon-carbon bond.

alkenyl group - the hydrocarbon group formed when a hydrogen atom is removed from an alkene group.

alkoxide - an organic functional group formed when a hydrogen atom is removed from the hydroxyl group of an alcohol when it is reacted with a metal.

alkoxy group - functional group containing an alkyl group bonded to oxygen.

allotrope - a form of an elemental substance.

alloy - substance made by melting together two or more elements, at least one of which must be a metal.

alpha decay - spontaneous radioactive decay which produces an alpha particle or helium nucleus.

alpha radiation - the ionizing radiation released from radioactive decay emitting an alpha particle.

aluminum or aluminium - the name for the element with atomic number 13 and is represented by the symbol Al. It is a member of the metal group.

amalgam - any alloy of mercury and one or more other metals.

americium - radioactive metal with element symbol Am and atomic number 95.

amide - functional group containing a carbonyl group linked to a nitrogen atom.

amine - compound in which one or more hydrogen atom in ammonia is replaced by an organic functional group.

amino acid - an organic acid containing a carboxyl (-COOH) and amine (-NH₂) functional group along with a side chain.

amorphous - term describing a solid that does not have crystalline structure.

amphiprotic - species that can both accept and donate a proton or hydrogen ion.

amphoteric - substance capable of acting as either an acid or a base.

amphoteric oxide - oxide that can act as either an acid or a base in a reaction to produce a salt and water.

amu - atomic mass unit or 1/12th the mass of an unbound atom of carbon-12.

analytical chemistry - chemistry discipline that studies the chemical composition of materials and tools used to examine them.

angstrom - unit of length equal to 10^-10 meters.

angular momentum quantum number - ℓ, the quantum number associated with the angular momentum of an electron.

anhydrous - describes a substance that does not contain water or else is as concentrated as it can get.

anion - an ion with a negative electrical charge.

anode - electron where oxidation occurs; positive charged anode

antibonding orbital - molecular orbital with an electron outside the region between the two nuclei.

anti-Markovnikov addition - an addition reaction between an electrophilic compound HX and either an alkene or alkyne in which the hydrogen atom bonds to the carbon with the least number of hydrogen atoms and X bonds to the other carbon.

antimony - Antimony is the name for the element with atomic number 36 and is represented by the symbol Kr. It is a member of the metalloid group.

anti-periplanar - periplanar conformation where the dihedral atom between atoms is between 150° and 180°.

aqueous - describes a system containing water.

aqueous solution - a solution in which water is the solvent.

aqua regia - mixture of hydrochloric and nitric acids, capable of dissolving gold, platinum, and palladium.

argon - Argon is the name for the element with atomic number 18 and is represented by the symbol Ar. It is a member of the noble gases group.

aromatic compound - an organic molecule that contains a benzene ring.

Arrhenius acid - species that dissociates in water to form protons or hydrogen ions.

Arrhenius base - species that increases the number of hydroxide ions when added to water.

arsenic - metalloid with element symbol As and atomic number 33.

aryl - a functional group derived from a simple aromatic ring when one hydrogen is removed from the ring.

astatine - Astatine is the name for the element with atomic number 85 and is represented by the symbol At. It is a member of the halogen group.

atom - the defining unit of an element, which cannot be subdivided using chemical means.

atomic mass - average mass of atoms of an element.

atomic mass unit (amu) - 1/12th the mass of an unbound atom of carbon-12, used to represent atomic and molecular masses.

atomic number - the number of protons in the nucleus of an atom of an element.

atomic radius - value used to describe the size of an atom, usually half the distance between two atoms just touching each other.

atomic solid - solid in which atoms are bonded to other atoms of the same type.

atomic volume - volume occupied by one mole of an element at room temperature.

atomic weight - average mass of atoms of an element.

atmosphere - surrounding gases, such as the gases surrounding a planet that are held in place by gravity.

ATP - ATP is the acronym for the molecule adenosine triphosphate. 

Aufbau principle - idea that electrons are added to orbitals as protons are added to an atom.

austenite - the face-centered cubic crystalline form of iron.

Avogadro's Law - relation that states equal volumes of all gases contain the same number of molecules at the same pressure and temperature.

Avogadro's number - the number of particles in one mole of a substance; 6.0221 x 10²³

azeotrope - a solution that retains its chemical composition when distilled.

azimuthal quantum number - the quantum number associated with the angular momentum of an electron, determining the shape of its