Since we are already given the balanced equation:
→
We can derive the molar ratios as: 1:2:1:1
That being said, we are given 0.172 moles of bromine (), so it has a ratio of 1:1 with sodium bromide (
).
So we can take from that ratio, that when 0.172 moles of bromine are used, we are, in turn, going to get 0.172 moles of sodium bromide produced.
2.1618 grams of P4 is required to produce 4.21x10^22 molecules of phosphorus trifluoride.
Explanation:
The balanced chemical reaction for formation of PF3 from yellow phosphorus is given by:
P4 + 6F2 ⇒ 4PF3
1 mole of P4 reacts to give 4 moles of PF3
It is given that 4.21x10^22 molecules of PF3 are produced
so the number of moles can be calculated by the relation
number of molecules = number of moles × Avagadro number
number of moles =
n =
n= 0.06989 moles of PF3 is formed.
Applying stoichiometry,
1 mole of P4 gives 4 moles PF3
x mole will produce 0.06989 moles of PF3
=
4x= 0.0698 × 1
x =
x= 0.01745 moles of P4 will be required.
The weight of the phosphorus can be obtained by number of moles × atomic mass of one mole of P4
= 0.01745 × 123.89
= 2.1618 grams of P4.