The pH of a solution is a measure of its acidity or basicity, defined as pH = -log₁₀[H⁺], where [H⁺] is the concentration of hydrogen ions in moles per liter. The pOH is defined similarly: pOH = -log₁₀[OH⁻]. At 25°C, pH + pOH = 14 (the water ion product constant, Kw = 1×10⁻¹⁴). A pH of 7 is neutral (pure water), below 7 is acidic, and above 7 is basic (alkaline). The calculator allows input of pH, pOH, [H⁺], or [OH⁻] and computes all other values. This is essential for chemistry, biology, environmental science, medicine, and water quality analysis. Understanding pH is crucial for reactions, buffers, and many biological processes.
Chemistry Calculators
Avogadro’s Number Calculator – Moles to Particles & Vice Versa
What is Avogadro's Number?
Avogadro's number (NA) is a fundamental physical constant that represents the number of particles (atoms, molecules, ions, or other entities) in one mole of any substance. Its exact value, defined by the SI system since 2019, is:
NA = 6.02214076 × 10²³ mol⁻¹
One mole is the amount of substance that contains exactly 6.02214076 × 10²³ elementary entities. This definition links the macroscopic world (grams, kilograms) to the microscopic world (atoms, molecules). The number was named after the Italian scientist Amedeo Avogadro (1776–1856), who first proposed that equal volumes of gases at the same temperature and pressure contain the same number of molecules.
Key applications:
- Chemistry — converting between mass, moles, and number of atoms/molecules
- Physics — calculating the number of particles in a gas
- Materials science — determining atomic density and crystal structures
- Biochemistry — counting molecules in biological systems
Use this calculator to quickly convert between moles and the actual number of particles for any substance.
Solution Dilution Calculator – C1V1 = C2V2 Formula Tool
Solution dilution is the process of reducing the concentration of a solute in a solution by adding more solvent. The fundamental principle is the conservation of mass: the amount of solute remains constant before and after dilution. This is expressed by the equation C₁V₁ = C₂V₂, where C₁ is the initial concentration, V₁ is the initial volume, C₂ is the final concentration, and V₂ is the final volume. This relationship holds because the moles of solute (or mass) are the same in both solutions. To prepare a diluted solution, you calculate the volume of concentrated solution needed, then add solvent to reach the final volume. Dilution calculations are essential in chemistry, biology, medicine, pharmacy, and everyday laboratory work. This calculator allows you to solve for any variable (C₁, V₁, C₂, V₂) when the other three are known.