One problem with organic chemistry is that we tend to focus on one molecule at a time, we forget that there are many, many molecules undergoing the reaction. Assume you started with exactly 1 g of bromobenzene, how many MOLECULES OF bromobenzene is this?

1g of bromobenzene = 3.84× 10^21 molecules

Explanation:

Molar mass of bromobenzene (C6H5Br)= 79.9+(12×6)+ 5= 156.9

156.9g(1mole) has 6.023×10^23 molecules

This implies that 1g will contain 6.023×10^23/156.9 = 3.84×10^21 molecules

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

the product of the pressure and volume is also constant