Pressure — Definition, Formula, Properties & Uses | AllChemicals | AllChemicals

Q: What is the formula for Pressure?

The formula or notation for Pressure is: P = F/A; SI unit: Pa (N/m²); 1 atm = 101,325 Pa = 760 mmHg

Formula / Notation	P = F/A; SI unit: Pa (N/m²); 1 atm = 101,325 Pa = 760 mmHg
Also Known As	Force per unit area, P, atmospheric pressure, gauge pressure, absolute pressure

What is Pressure?

The force exerted per unit area, measured in pascals (Pa) in SI units. Atmospheric pressure is 101,325 Pa (1 atm). Gas pressure results from molecular collisions with container walls. Pressure affects gas volume (Boyle's law), phase behavior, and reaction equilibria.

Formula & Notation

P = F/A; SI unit: Pa (N/m²); 1 atm = 101,325 Pa = 760 mmHg

Other Names / Synonyms: Force per unit area, P, atmospheric pressure, gauge pressure, absolute pressure

Properties & Characteristics

Pressure is the force per unit area applied perpendicular to a surface: P = F/A. SI unit: pascal (Pa = N/m²). Other common units: atm, bar, mmHg (torr), psi. Fluid pressure increases with depth: P = P₀ + ρgh. Boyle's law: PV = const (at constant T). Gas pressure arises from molecular collisions with container walls. Atmospheric pressure decreases with altitude. Osmotic pressure is a special form of pressure arising from solvent activity differences across a membrane.

Uses & Applications

Pressure is fundamental in: gas law calculations (PV = nRT), chemical engineering (design of reactors, distillation columns, compressors), materials science (high-pressure synthesis of diamond, yttrium-barium copper oxide superconductors), analytical chemistry (HPLC pump pressure: 400-1000 bar), and medicine (blood pressure measurement, anaesthetic gas delivery).

Safety Information

High-pressure vessels (reactors, autoclaves, compressed gas cylinders) must be rated, inspected, and equipped with pressure relief devices. Rapid pressure release can cause projectile fragments or sudden cooling (cryogenic burns from CO₂). Vacuum systems (negative pressure) present implosion hazards with glass equipment.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Pressure

Formula P = F/A; SI unit: Pa (N/m²); 1 atm = 101,325 Pa = 760 mmHg

Index All "P" terms

Synonyms Force per unit area, P, atmospheric pressure, gauge pressure, absolute pressure

Frequently Asked Questions

What is Pressure?

The force exerted per unit area, measured in pascals (Pa) in SI units. Atmospheric pressure is 101,325 Pa (1 atm). Gas pressure results from molecular collisions with container walls. Pressure affects gas volume (Boyle's law), phase behavior, and reaction equilibria.

What is Pressure used for?

Is Pressure hazardous?

What is the formula for Pressure?

More "P" Terms

P-type Semiconductor Pairing Pairing Energy Palladium Pd Parachor [P] = M(γ)^(1/4) / (ρ_L - ρ_V) Paramagnetic χ_m > 0; unpaired electrons; μ = √(n(n+2)) BM (n = unpaired electrons) Paramagnetism Partial Ionic Character % ionic = (1 - e^(-Δχ²/4)) × 100% Partial Pressure Partial Pressure p_i = x_i × P_total; P_total = Σp_i Particulate Matter Parts Per Million ppm = mg/L (water) or mg/kg; = (mass solute/mass solution) × 10⁶

View all "P" terms →