Question

what is amount of substance ? why mass length and time most fundamental quantities?​

Answer 1

Answer:

1.In chemistry, the amount of substance in a given sample of matter is defined as the number of discrete atomic-scale particles in it divided by the Avogadro constant NA. In a truly atomistic view, the amount of substance is simply the number of particles that constitute the substance.

2.Length, mass and time cannot be derived from one another, that is these quantities are independent. (ii) All other quantities in mechanics can be expressed in terms of length, mass and time.

Answer 2

Answer:

amount of substance simply refers to how much is the amount of substance which may be particles, molecules which is measured in moles.

1 mole = 6.022×10^23 particles

Length,mass and time are the most fundamental quantities becoz these are the basic quantities which are a part of most of the derived quantities.