For drivers in the UK, the legal limit of the concentration of ethanol (molar mass 46 g mol-1) in the blood mg per 100 cm^3. What is equivalent to a concentration of?

1 Answer
Oct 8, 2016

Answer:

In England and Wales, the blood alcohol limit is #80*mg" per 100"# #mL# of blood,........

Explanation:

And in Scotland (where there are notable dipsos!) it is #50*mg" per 100"# #mL# of blood.

And thus is molar terms, we simply turn the mass into a molar quantity:

#"Molarity"# #=# #"Moles of solute"/"Volume of solution"#

#=# #(80*cancel(mg)xx10^-3*cancel(g)*cancel(mg^-1))/(46*cancel(g)*mol^-1)xx1/(100*cancel(mL)xx10^-3*L*cancel(mL^-1))#

#=# #0.017*mol*L^-1# in England.