Answer:
The ionization energy (in kJ/mol) of the helium ion is 21,004.73 kJ/mol .
Explanation:

Z = atomic mass
n = principal quantum number
Energy of the electron in n=1,

Energy of the electron in n = ∞

Ionization energy of the
ion:


To convert in into kj/mol multiply it with 

Using boyles law
p1v1=p2v2
v1=3.88
v2=5.43
p1=707
p2=?
707x3.88=p2x5.43
2743.16/5.43=p2
p2=505mmHg
Answer:
Cooper and zinc if I remember right
It describes how, when particles/mc/elements react, despite forming different substances the mass is neither created nor destroyed but only converted.