Chemistry

Articles about matter, substances, reactions and chemical science.

Articles in this category: 1474 Updated: April 29, 2026 Page 24 / 31

Reactivity (chemistry)

Reactivity series

Reagent

Realgar

Realgar — the red arsenic sulfide mineral

Rearrangement reaction

Red

Red (color)

Redox

Redox (Reduction–Oxidation) Reactions: Principles, Examples, and Applications

Reducing agent

Reducing agent (reductant)

Reduction

Reduction: concepts, types and interdisciplinary applications

Reduction (chemistry)

Refining

Refining: Principles, Methods, Uses and Impacts

Refrigerant

Refrigerant — properties, refrigeration cycle, uses and environmental issues

Registration, Evaluation, Authorisation and Restriction of Chemicals

Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH)

Relative atomic mass

Relative atomic mass: definition, calculation, and significance

Rhenium

Rhenium (element Re)

Rhodium

Rhodium: properties, occurrence, uses, and market significance

Rieke metals

Risk and Safety Statements

Risk and Safety Statements (R‑ and S‑phrases)

Rocket fuel

Rocket fuel (rocket propellant)

Roentgenium

Room temperature

Rotary evaporator

Round-bottom flask

Round-bottom flask: design, uses, and laboratory practice

Rubber

Rubidium

Rubidium — properties, history, occurrence and uses

Rubidium chloride

Rubidium chloride (RbCl)

Rubidium hydride

Rubidium hydroxide

Rubidium hydroxide (RbOH)

Rubidium nitrate

Rubidium nitrate (RbNO3): properties, preparation, uses and safety

Rubidium oxide

Rubidium oxide (Rb2O)

Rust

Rust (iron oxide): causes, chemistry, prevention, and impacts

Ruthenium

Ruthenium — properties, occurrence, uses, and history

Rutherfordium

Rutherfordium (element 104)

s-block

S-block elements of the periodic table

Saccharide

Saccharide: types, structure, and biological roles

Safety data sheet

Safety data sheet (SDS): purpose, content, and practical uses

Salicylic acid

Salicylic acid: properties, history, and common uses

Saline

Salt

Salt (chemistry): structure, properties, and uses

Samarium

Samarium (chemical element)

Sapphire

Sarin

Saturated fat

Saturated fat: definition, properties, dietary sources, and health context

Saturation (chemistry)

Scandium

Seaborgium

Seaborgium (element 106)

Selectivity

Selenate