Question

You are asked to calculate the concentration of a NaCl (in water) solution in several ways and are given the following information: 20 g NaCl, 250 mL solution, 250 g H2O, Molecular weight of NaCl = 58.44 g/mole.
(b) Calculate the mass/mass percent concentration
(C) Calculate the molarity of the solution

Answer 1

For the second part follow these steps and tell me what you get.

Our solute is going to be NaOH and we have 20 grams of that. what you need to do is to convert grams of NaOH to moles of NaoH. by doing the following:

grams NaOH * (Molecular weight of NaOH) = moles of NaOH.

Now we take our solvent, that's what we are putting NaOH into and that's water.

we have 250 mL of H2O. so we need to convert that to liters.

250mL* (1L)/(1000mL) = 0.25L of H2O.

now we have to find the molarity which is the concentration of NaOH in our solution.

Molarity = Moles of NaOH/(liters of solution) = moles/liter.