I think the answer the students average is 15 km?
Answer:

Explanation:
Step 1. Identify the Group that contains X
We look at the consecutive ionization energies and hunt for a big jump between them

We see a big jump between n = 2 and n = 3. This indicates that X has two valence electrons.
We can easily remove two electrons, but the third electron requires much more energy. That electron must be in the stable, filled, inner core.
So, X is in Group 2 and P is in Group 15.
Step 2. Identify the Compound
X can lose two valence electrons to reach a stable octet, and P can do the same by gaining three electrons.
We must have 3 X atoms for every 2 P atoms.
The formula of the compound is
.
Answer: The volume occupied by 2.50 moles of
gas at STP is 56.0L
Explanation:
According to ideal gas equation:

P = pressure of gas = 1 atm (at STP)
V = Volume of gas = ?
n = number of moles = 2.50
R = gas constant =
T =temperature =
(at STP)


Thus the volume occupied by 2.50 moles of
gas at STP is 56.0L
Answer:
I think it is mixture and of chemical reaction
Answer: wait im gonna search some info.
Explanation:I come back with an asnwer for you