what is the weigh out

Question

A student wishes to prepare 250-mL of a 0.171 M sodium acetate solution using solid sodium acetate, a 250-mL volumetric flask, and deionized water.

(a) How many grams of sodium acetate must the student weigh out?

 g

(b) Which of the following would NOT be an expected step in the procedure used by the student?

1. Carefully transfer the salt sample to the volumetric flask.
2. Dry the flask in a drying oven.
3. Add additional water to the flask, mixing as each portion is added.

Answer 1

Here you will need to calculate/know the molar mass of sodium acetate NaC₂H₃O₂ = 82.0 g/mole.

You need to also remember when given the molarity (eg. 0.171 M) this means that in 1 liter (1000 mL) of the solution in question there are 0.171 moles of the substance dissolved. Using this information you can calculate the grams of the solute (substance dissolved) needed to prepare 250 mL...

250 mL x ( 0.171 mol NaC₂H₃O₂ ⁄ 1000 mL soln) x (82.0 g NaC₂H₃O₂ ⁄ 1 mol NaC₂H₃O₂) = 3.51 g

The second part involves techniques which are shared with you in the lab about preparing solutions using a volumetric flask and how to handle/ prepare glassware. Review that information...