How many molecules of lactose are there in one liter of buttermilk?

1 answer

According to the site below there is 3-5% lactose in butter milk.
https://en.wikipedia.org/wiki/Lactose_content_of_foods

As an average if we take 4%, and if we assume that is % w/v, there will be 4 g lactose in 100 mL or 40 g/1000 mL.
# mols in 40g is mols = grams/molar mass
Then in 1 mol there are 6.02E23 molecules. You can go from there.