How many grams are there in 3.4 x 10^24 molecules of NH3? (show work)

An aqueous solution of hydroiodic acid is standardized by titration with a 0.186 m solution of calcium hydroxide. if 26.5 ml of base are required to neutralize 20.3 ml of the acid, what is the molarity of the hydroiodic acid solution? m hydroiodic acid

If a 12-v battery is connected to a circuit that has a current of 3.0 a, what is the total resistance in the circuit? 36 ohms 4 ohms 0.25 ohms

Express the following number in scientific notation. 0.026890 =