Answer:
1&2.
1&2.The mole concept is a convenient method of expressing the amount of a substance. Any measurement can be broken down into two parts – the numerical magnitude and the units that the magnitude is expressed in. ... This is where the mole concept is widely used
3.(diko Alam)
4. The specific number of molecules in one gram-mole of a substance, defined as the molecular weight in grams, is 6.02214076 × 1023, a quantity called Avogadro's number, or the Avogadro