1) Calculate the volume of 50% by mass NaOH needed to prepare 1.0 L of 0.1 M NaOH solution. (The density of 50% by mass NaOH is 1.50 g per milliliter of solution.)

yes the answer is total mass in unchanged   : )

to improve her experimental investigation, dalila should add a row in which no fertilizer is used. by a having a contrasting row in which no fertilizer is used, she will have a control group that will her understand the effects of the fertilizer in the plant developments vs the development of the plant when no fertilizer is used.