Answer:
5g ($120)
Explanation:
The amount of chemical needed for assay is 3 ml of 250 mM solution of a chemical
Molarity (M) = number of moles / volume in L
number of mole = M × volume in L
M of the chemical = 250 mM = 250 / 1000 = 0.25 M
number of moles = 0.25 × ( 3 / 1000) in L = 0.00075 m
mass of the chemical needed = 0.00075 × molar mass = 0.00075 × 156 = 0.117 g for each assay.
mass needed for 40 assay = 40 × 0.117 = 4.68 g
It is therefore wise for him to buy the 5 g ( $ 120), though the 10 g and 25 g yields better prices per gram, they much more than what he needed for the assay.
Renewable energy source
reduces electric bills
low maintenance costs
reduced needs for fossil fuels and foreign oils
Butanoic acid (Butyric acid)
I know why it wouldn't be a good idea: Some bacteria are good, for example some might help fight disease. (sorry I don't know the rest)
0.86 to 088, hope this helps :)