The best substance to heat up the fastest would be blue fire
that's your work bro do by your own
I think you mean ionic bond and not conic bond. The pair of elements that form an ionic bond are barium and chlorine.
Answer: The molar mass of each gas
Explanation:
Mole fraction is the ratio of moles of that component to the total moles of solution. Moles of solute is the ratio of given mass to the molar mass.

Suppose if there are three gases A, B and C.
a) 
b) 
c) 
moles of solute =
Thus if mass of each gas is known , we must know the molar mass of each gas to know the moles of each gas.
Is to find the problem to the investigation