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Pascal (Pa)

Quantity: pressure · Category: SI derived unit

The pascal is the SI derived unit of pressure: one newton of force per square meter. It is the standard pressure unit in SI, though its small size means kilopascals are far more common in chemistry problems. One standard atmosphere equals exactly 101325 Pa.

Relation to SI

1 Pa = 1 N/m² = 1 kg/(m·s²); 1 atm = 101325 Pa

Examples

  • Atmospheric pressure ≈ 101.325 kPa
  • Ideal gas law: P in Pa gives V in m³, with R = 8.314 J/(mol·K)
  • Weather maps quote pressure in hectopascals (hPa); 1 hPa = 100 Pa