Valence electrons hope this helps
According to Raoult's low:
We will use this formula: Vp(Solution) = mole fraction of solvent * Vp(solvent)
∴ mole fraction of solvent = Vp(Solu) / Vp (Solv)
when we have Vp(solu) = 25.7 torr & Vp(solv) = 31.8 torr
So by substitution:
∴ mole fraction of solvent = 25.7 / 31.8 =0.808
when we assume the moles of solute NaCl = X
and according to the mole fraction of solvent formula:
mole fraction of solvent = moles of solvent / (moles of solvent + moles of solute)
by substitute:
∴ 0.808 = 0.115 / (0.115 + X)
So X (the no.of moles of NaCl) = 0.027 m
A. Breaking Bread, because you can rip or cut it and it is still bread.
hope that helps :)
Answer : The heat released by the combustion of 1.121 mol of hexane (kJ) is, 
Explanation :
The given balanced reaction is,

Given:
Moles of hexane = 0.121 mol
= -8326 kJ/mol
The negative sign indicate that the reaction exothermic or amount of heat released.
As, 1 mole of hexane released heat = 8326 kJ
So, 0.121 mole of hexane released heat = 8326 × 0.121 = 1007.446 ≈ 
Therefore, the heat released by the combustion of 1.121 mol of hexane is
.
Because Nitrogen is required to biosynthesize basic building blocks of plants, animals and other life forms.