Pharmaceutical calculations questions.

A prescription calls for 50 milligrams of chlorpheniramine maleate. Using a pre-
scription balance with a sensitivity requirement of 6 milligrams, explain how you would obtain the required amount of chlorpheniramine maleate with an error not greater than 5%.

A prescription balance has a sensitivity requirement of 0.006 gram. Explain how
you would weigh 0.012 gram of atropine sulfate with an error not greater than  5%, using lactose as the diluent.

A torsion prescription balance has a sensitivity requirement of 4 milligrams. Explain how you would weigh 5 milligrams of hydromorphone hydrochloride with
an error not greater than 5%. Use lactose as the diluent.

A torsion prescription balance has a sensitivity requirement of 0.004 gram. Explain how you would weigh 0.008 gram of a substance with an error not greater than 5%.

A prescription balance has a sensitivity requirement of 6.5 milligrams. Explain
how you would weigh 20 milligrams of a substance with an error not greater than
2%.

A formula calls for 0.6 milliliter of a coloring solution. Using a 10-milliliter graduate calibrated from 2 to 10 milliliters in 1-milliliter units, how could you obtain the desired quantity of the coloring solution by the aliquot method? Use water as the diluent.

Using a 10-milliliter graduate calibrated in 1-milliliter units, explain how you
would measure 1.25 milliliters of a dye solution by the aliquot method. Use water
as the diluent.

The formula for 100 milliliters of pentobarbital sodium elixir calls for 0.75 milliliter of orange oil. Using alcohol as a diluent and a 10-milliliter graduate calibrated in 1-milliliter units, how could you obtain the desired quantity of  orange oil?

If 30 g of a 1% hydrocortisone ointment were diluted with 12 g of Vaseline, what would be the concentration of hydrocortisone in the mixture?

How many grams of 20% benzocaine ointment and how many grams of ointment base (diluent) should be used in preparing 5 lb. of 2.5% benzocaine ointment?