The balanced chemical reaction is:
C3H8 + 5O2 = 3CO2 + 4H2O
We are given the amount of C3H8 to be used for the reaction. This will be the starting point for the calculations.
73.7 g C3H8 (1 mol C3H8 / 44.11 g C3H8) ( 5 mol O2 / 1 mol C3H8 ) ( 32 g O2 / 1 mol O2 ) = 267.3 g O2
The molecular formula iust is how many total number of atoms of each type are present in a molecule.
Have a close look at the structure, the large sized black atoms shown here are Carbons. Count the number of carbons, total of 5 carbons.
The smaller ones are hydrogens. Count the hydrogens they are 12.
The symbol for Carbon is C and Hydrogen is H. The molecular formula is thus C5H12.
The iupac name is Pentane
Volatility is the property of a liquid to change phase to gas. As you know, the molecular arrangement of liquids and gases differ in the inter-spaces. The molecules of the gas is more widely distributed so they have less intermolecular forces. Therefore, a liquid with high volatility has very low intermolecular forces. This means that they could be easily separated from each other to conform to the molecular arrangement of a gas.
The parameter that is well associated with volatility is vapor pressure. Think of it this way, when the vapor pressure equals the atmospheric pressure, the liquid boils and changes phase into gas. So, we can say that a liquid with high volatility exhibits high vapor pressure. In this case, it would only take less energy for the vapor pressure to reach the much higher atmospheric pressure.
