So they can tell what exact species it is.
Answer:
A - Liquid molecules forming a gas and gas molecules forming a
liquid are equal in number.
Explanation:
A P E X
Carbon has a tendency to form covalent bonds.
one mole of P weights about 31 grams
in one mole there are 6.022*10^23 atoms
we use the rule of threes
6.022*10^23atoms......weight..........31 grams
3.45*10^23 atoms.........weight...........x grams
x=(3.45*10^23*31)/6.022*10^23
x=106.95/6.022=<u><em>17.76 grams</em></u>