Home Wikituition Browse all terms Categories
Random term

Foundations of Chemistry

60 terms · page 1 of 3


A–Z
All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Filtering by: Foundations of Chemistry Clear all
Foundations of Chemistry

Accuracy

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

% error = |measured − true| / true × 100 Dimensionless
Foundations of Chemistry

Allotropy

The existence of an element in two or more distinct structural forms within the same physical state.

Dimensionless
Foundations of Chemistry

Anhydrous

Describing a substance from which all water, including water of crystallisation, has been removed.

Dimensionless
Foundations of Chemistry

Anion

A negatively charged ion produced when an atom or molecule gains one or more electrons.

X + n e⁻ → Xⁿ⁻ C (charge)
Foundations of Chemistry

Atom

The smallest particle of an element that retains the chemical identity of that element.

Dimensionless
Foundations of Chemistry

Atomic Mass Unit

A mass unit defined as exactly one twelfth the mass of a free, unbound carbon-12 atom in its ground state.

1 u = 1.66053907 × 10⁻²⁷ kg u (Da)
Foundations of Chemistry

Atomicity

The number of atoms present in one molecule of an element.

Dimensionless
Foundations of Chemistry

Avogadro's Number

The number of elementary entities in one mole of substance, fixed by definition at 6.02214076 × 10²³ mol⁻¹.

N = n × N_A mol⁻¹
Foundations of Chemistry

Cation

A positively charged ion produced when an atom or molecule loses one or more electrons.

M → Mⁿ⁺ + n e⁻ C (charge)
Foundations of Chemistry

Centrifugation

A separation technique that uses rapid rotation to generate an effective gravitational field, forcing denser components to the bottom of a…

RCF = 1.118 × 10⁻⁵ × r × N² g (RCF)
Foundations of Chemistry

Chemical Change

A change in which the atoms of one or more substances are rearranged into new substances with different properties.

Dimensionless
Foundations of Chemistry

Chemical Formula

A symbolic notation that states which elements a substance contains and in what proportions, using element symbols and subscripts.

Dimensionless
Foundations of Chemistry

Chemical Property

A characteristic that describes how a substance transforms into a different substance, observable only during a chemical reaction.

Various
Foundations of Chemistry

Chemical Symbol

The one-, two- or three-letter abbreviation used internationally to represent an element.

Dimensionless
Foundations of Chemistry

Compound

A pure substance formed when two or more different elements combine chemically in a fixed, whole-number mass ratio.

Dimensionless
Foundations of Chemistry

Crystallisation

A purification technique in which a solid is separated from solution as an ordered crystalline lattice.

Dimensionless
Foundations of Chemistry

Dalton's Atomic Theory

The 1808 model proposing that elements consist of indivisible atoms that are identical within an element and combine in fixed whole-number…

Dimensionless
Foundations of Chemistry

Decantation

The separation of a liquid from a settled solid or a denser immiscible liquid by carefully pouring off the upper layer.

Dimensionless
Foundations of Chemistry

Deliquescence

The property of a solid that absorbs enough water vapour from the air to dissolve completely in the water it takes up.

Dimensionless
Foundations of Chemistry

Density

The mass of a substance contained in a unit volume, a characteristic intensive property of each material.

ρ = m / V g/cm³
Foundations of Chemistry

Dimensional Analysis

A calculation method that tracks and cancels units through a chain of conversion factors to reach the required quantity.

given quantity × (desired unit / given unit) = answer Various
Foundations of Chemistry

Distillation

A separation technique that exploits differences in volatility by vaporising a liquid and condensing the vapour in a separate vessel.

Dimensionless
Foundations of Chemistry

Element

A pure substance composed entirely of atoms that share the same atomic number and therefore cannot be split into simpler substances by…

Dimensionless
Foundations of Chemistry

Empirical Formula

The chemical formula giving the simplest whole-number ratio of atoms of each element in a compound.

ratio = (mass % ÷ A_r), normalised Dimensionless