How do I calculate the mass of NaOH needed to produce a 0.400M aqueous solution of sodium hydroxide and H2O?

(0.700 L) x (6 mol/L NaOH) x (39.99715 g NaOH/mol) = 168 g NaOH So: I would dissolve 168 grams of NaOH to a final volume of 700 ml. With water. (700 mL) x (3.5 g / 100 mL) = 24.5 g So: I would dissolve 24.5 g of NaCl to a finalvolume of 700 ml.

With water. Supposing you really mean "m" and not "M": (0.003 mol / 1 kg H2O) x (242 g/mol) = 0.726 g / 1 kg H2O (500 g) x (0.726 g / 1000 g H2O) = 0.363 g So: I would dissolve .363grams of Fe(NO3)3 with 500 g of water.

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