The concentration of alcohol (CH3CH2OH)
in blood, called the "blood alcohol concentration" or BAC, is given in units of grams of alcohol per 100 mL
of blood. The legal definition of intoxication in many states of the United States is a BAC of 0.08 or higher. What is the concentration of alcohol, in terms of molarity, in blood if the BAC is 0.08?
To convert BAC from grams per 100mL to molarity, we need to first convert grams of alcohol to moles, and then divide by the volume of blood in liters.
The molar mass of ethanol (CH3CH2OH) is 46.07 g/mol.
BAC of 0.08 g/100mL can be converted to g/L by dividing by 10:
0.08 g/100mL = 0.008 g/mL
Now we need to convert this value to moles:
0.008 g / 46.07 g/mol = 0.0001736 mol/L
So, the molarity of alcohol in blood with a BAC of 0.08 is approximately 0.0001736 M.