chemistry stoichiometry glossary

8/10/2019 Chemistry Stoichiometry Glossary

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STOICHIOMETRY

GLOSSARY

Ac id

According to the Lowry-Bronsted theory of acids and bases, an acid is a proton donor.

Al iquot

The volume of the sample, as measured by a pipette, prior to a titration.

Amphiprotic

Can act as either an acid or a base, depending on the situation.

Amphoteric

Can act as either an acid or a base, depending on the situation.

Anhydrous

Without water. The molecule has no associated water molecules.

Anion

Negative ion, formed when a neutral atom has gained electrons.

Atomic Number

The number of protons in the nucleus of the atom.

Avogadros Constant

6.023 x 1023particles (atoms, ions or molecules), or 1 mole of substance.

Base

According to the Lowry-Bronsted theory of acids and bases, a base is a proton acceptor.That is, a species that will accept an extra H+.

Cation

Positive ion, formed when a neutral atom has lost electrons.

Chemical Equation

Shows the relative amounts, in mole, of reactants and products.

Chemical Formula

Chemical symbol that represent elements, ions and compounds.

Combustion Reaction

A reaction with oxygen. The reaction will be strongly exothermic.


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Compound

A substance that consists of one or more elements that are chemically bonded together.

Conjugate Acid-Base Pair

Chemical species that differ by exactly one proton, H

+

.

Conjugate Redox Pair

Consists of a reactant and a product. The chemical formulae will be based on the sameelement, but have different charges and may differ in the number of hydrogen and/or oxygenatoms.

Diprotic Acid

An acid that can donate two hydrogen ions per molecule of acid.

Dissociation

Splitting up into its ions when in an aqueous solution.

Empirical Formula

The smallest ratio of elements in the compound, given as whole numbers.

End Point

The point of a titration that occurs when a permanent colour change is first observed, andthe titration is stopped.

Equivalence Point

The point of a titration where chemically equivalent amounts of the two solutions, accordingto the mole ratios shown by the equation, are present.

Excess Reactant

The reactant that has some leftover after a chemical reaction is complete.

Formula Mass

The sum of the relative atomic masses of each atom in the ionic formula.

Hydrated - With water

The molecular formula is a complex that includes associated water molecules.

Ion

An atom that has gained or lost electrons and carries an electrical charge.

Ionic equation

A balanced chemical equation that has all spectator ions omitted.

Isotopes

Atoms with the same atomic number and the same mass number.


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Limit ing Reactant

The reactant that is completely consumed during a chemical reaction.

Mass Number

The number of protons plus neutrons in the nucleus of the atom.

Molar Mass

The mass of one mole of a substance, equal to the relative mass expressed in grams.

Molar Volume (Vm)

The volume that one mole of a gas occupies.

Mole

6.023 x 1023particles (atoms, ions or molecules).

Molecular Formula

The number of atoms of each element that are in a molecule.

Monoprotic Acid

An acid that can donate one hydrogen ion per molecule of acid.

Oxidant

Allows the oxidation of another species, by itself undergoing reduction.

Oxidation Numbers

Indicate the charge that an atom would have if all bonds were broken and the moreelectronegative element kept all of the electrons in the bond. They are used to identifyoxidation and reduction reactions.

Oxidation Reaction

Involves the loss of electrons, and the oxidation number goes up.

pH

A measure of the concentration of H+(aq), or H3O+(aq), in the solution.

Polyprotic Acid

An acid with more than one proton.

Precipitate

The solid that forms when two solutions are mixed.

Precipitation Reaction

A reaction between two solutions that results in the formation of a solid, which is called aprecipitate.


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Primary Standard

A standard solution that is prepared by dissolving a known mass in a known volume ofwater.

Redox Reaction

Involves the transfer of electrons.

Reductant

Allows the reduction of another species, by itself undergoing oxidation.

Reduction Reaction

Involves the gaining of electrons, and the oxidation number goes down.

Relative Atomic Mass (RAM or AR)

The weighted average of all relative isotopic masses as they occur in a natural sample of theelement.

Relative Isotopic Mass (RIM)

The mass of an isotope, relative to Carbon-12.

Relative Molecular Mass (RMM or MR)

The sum of the relative atomic masses of each atom that is present in a single molecule.

Salt

One of the products of an acid-base reaction. It is the substance formed when the anionfrom the acid joins with the cation from the base.

Secondary Standard

A standard solution where the concentration is determined by titrating it against a primarystandard.

Solute

A substance that is dissolved in a solvent.

Solution

A solute dissolved in a solvent.

Solvent

A liquid in which a solute is dissolved.

Spectator Ions

Ions that are present but do not take part in a chemical reaction.

Standard Laboratory Condi tions (SLC)

Temperature is 25 C and pressure is 1 atm. The molar volume 24.5 L


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Standard Solution

A solution where the concentration is known accurately.

Standard Temperature and Pressure (STP)

Temperature is 0C and pressure is 1 atm. The molar volume is 22.4 L

Strong Acid

An acid that completely dissociates in water to form ions.

Titration

A procedure that involves the reaction of two solutions in order to accurately determine theconcentration of one of the solutions.

Titre

The volume of a solution, as measured by the burette following a titration.

Triprotic Acid

An acid that can donate three hydrogen ions per molecule of acid.

Weak Acid

An acid that shows little dissociation in water.


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chemistry stoichiometry glossary

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