Volatile liquids vaporize rapidly from opened containers or spills. Some vapours, such as those from gasoline (C8H18), contribute to the formation of smog. Calculate the volume at STP occupied by vapours from 34.1 g of spilled gasoline, C8H18 (assume complete vaporization of the gasoline (C8H18(l)).
To solve this problem, we need to first calculate the number of moles of gasoline spilled, and then use the ideal gas law to find the volume occupied by the vapours at STP.
1. Calculate the number of moles of C8H18 in 34.1 g of gasoline:
Molar mass of C8H18 = 12(8) + 1(18) = 114 g/mol
Number of moles = mass / molar mass
Number of moles = 34.1 g / 114 g/mol
Number of moles = 0.299 moles
2. Use the ideal gas law to calculate the volume at STP:
PV = nRT
Where:
P = pressure = 1 atm
V = volume
n = number of moles = 0.299 moles
R = ideal gas constant = 0.0821 L.atm/mol.K
T = temperature = 273 K
Rearranging the equation to solve for V:
V = nRT / P
V = (0.299 moles)(0.0821 L.atm/mol.K)(273 K) / 1 atm
V = 6.72 L
Therefore, the volume at STP occupied by the vapours from 34.1 g of spilled gasoline (C8H18) is 6.72 liters.