Question

A 0.25 gr (grain) of phenobarbital is how many milligrams?

A) 0.25 mg
B) 25 mg
C) 2.5 mg
D) 16.2 mg

Answer 1

To convert grains to milligrams, multiply the amount in grains by the conversion factor of 64.79891 milligrams per grain. Thus, 0.25 grains of phenobarbital is 16.2 milligrams.

Step-by-step explanation:

To convert the weight of phenobarbital from grains to milligrams, it is important to know the conversion factor. There are 64.79891 milligrams in one grain. To convert 0.25 grains to milligrams:

• Multiply the number of grains (0.25) by the conversion factor (64.79891).
• The calculation will be 0.25 grains * 64.79891 mg/grain = 16.199775 mg.

Therefore, 0.25 grains of phenobarbital is 16.2 milligrams when rounded to one decimal place, which corresponds to option D.