Foundations of Chemistry
7 terms
Percentage Composition
Foundations of Chemistry
Dimensionless
The proportion by mass of each element in a compound, expressed as a percentage of the total mass.
% element = (n × A_r / M_r) × 100
Physical Change
Foundations of Chemistry
Dimensionless
A change that alters the form or state of a substance while leaving its chemical composition intact.
Physical Property
Foundations of Chemistry
Various
A characteristic of a substance that can be observed or measured without altering its chemical identity.
Polyatomic Ion
Foundations of Chemistry
C (charge)
A covalently bonded group of atoms that carries an overall electrical charge and behaves as a single unit in reactions.
Precision
Foundations of Chemistry
Dimensionless
The closeness of repeated measurements of the same quantity to one another, regardless of their accuracy.
RSD = (s / x̄) × 100
Pure Substance
Foundations of Chemistry
Dimensionless
Matter with a fixed chemical composition and a definite set of physical properties, comprising either a single element or a single compound.
Purity
Foundations of Chemistry
Dimensionless
The mass fraction of the desired substance in a sample, usually expressed as a percentage of the total mass.
purity % = (mass of pure substance / total mass) × 100