Mole (unit) containing of hydrogen atoms in it, weighing exactly 1.008 grams (same as the Ar of one hydrogen atom). The molar mass of a substance is the mass of a sample divided by the amount of substance in that sample. This is a constant for any given substance. Since the unified atomic mass unit (symbol: u, or Da) is defined as 1/12 of the mass of the C atom, it follows that the molar mass of a substance, measured in grams per mole, is numerically equal to its mean atomic or molecular mass expressed in Da. One can determine the amount
Intensity (physics) irradiance, depending on the background of the person using the term. Radiance is also sometimes called "intensity", especially by astronomers and astrophysicists, and in heat transfer. Intensity (physics) In physics, intensity is the power transferred per unit area, where the area is measured on the plane perpendicular to the direction of propagation of the energy. In the SI system, it has units watts per square metre (W/m). It is used most frequently with waves (e.g. sound or light), in which case the "average" power transfer over one period of the wave is used. "Intensity" can be applied to other circumstances