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

(v/v)%  =  10. mL ethanol   150 mL mouthwash   × 100% = 6.7 % (v/v) ethanol   how do I insert this calculation into my scientific calculator? can you please give me a detailed description I'm trying to watch videos but i don't know how to put into the calculator

5a.

While carrying out this practical class, all of the 25% (m/v) HCl solution was used up by the students and more of the solution had to be prepared. Concentrated hydrochloric acid containing 37% (m/v) HCl is available. What volume of concentrated hydrochloric acid should be made up to 100 mL with water in order to prepare more 25% HCl solution? Give your answer in mL to ONE decimal place. You do not need to include the units in your answer below.