Question

An empty weighing dish has a mass of 1.0041 ± 0.0002 g. After you add dried sodium chloride to the dish, the mass is 3.2933 ± 0.0002 g. You quantitatively transfer the sodium chloride into a 500.00 ± 0.05 mL volumetric flask and dilute to the mark with deionized water. The molar mass of sodium chloride is 58.440 g/mol. What is the absolute error in the concentration of the resulting solution? Report your answer normally to the correct number of significant figures with the correct unit.

Answer 1

Answer:

The correct answer to the following question will be "0.0013%".

Explanation:

The given values are:

Weight of an empty dish = 1.0041 ± 0.0002 g

Weight of dish + sodium chloride (NaCl) = 3.2933 ± 0.0002 g

Weight of NaCl = 2.2892 ± 0.0002 g

Now,

Volume of the solution = 500.00 ± 0.05 ± 0.0002

                                      = 500.00 ± 0.0502 ml

So,

Molarity = $\frac{W \ NaCl}{M \ NaCl} \times \frac{1000}{Volumes \ of \ solution}$

On putting the values in the above formula, we get

             = $\frac{(2.2892\addeq +0.0002)}{58.440}\times \frac{1050}{(500.00+0.0502)}$

             = ($3.917$ ± $0.0002$) × ($2$ ± $0.0502$)

             = ($0.7834$ ± $.00001004$)

Now,

Absolute error = $\frac{0.00001004}{0.7834}\times 100$

                         = $0.0013$%