Question

Example 1 : The percentage of chloride in MgCl, was reported by different persons as
32.64, 32.54, 3261 and 32-53% Calculate the mean deviation, standard deviation and
relative mean deviation in the results.​

Answer 1

Answer:

The mass of sample is 1.0 g.

The sample is 23% by mass in sodium.

The mass of sodium is 10023×1.0=0.23 g

The atomic masses of Na and Cl are 23.0 g/mol and  35.5 g/ mole.

In NaCl, 0.23 g of Na corresponds to 23.035.5×0.23=0.355  g of chlorine.

The molar mass of AgCl is 143.5 g/mol and the atomic mass of Cl is 35.5 g/mol.

A 2.0 g precipitate of AgCl separate out.

2.0 g of AgCl corresponds to  143.535.5×2.0=0.495 g of chlorine.

Out of 0.495 g of chlorine, 0.355 g of chlorine is from NaCl. The remaining 0.495−0.355=0.140 g is from KCl.

The molar mass of KCl is 74.6 g/mol. The atomic mass of chlorine is 35.5 g/mol.

0.140 of chlorine corresponds to  35.574.6×0.140=0.2928 g of KCl.

The mass of sample is 1.0 g. The mass of KCl is 0.294 g. The mass percent of KCl in sample is 1.00.2928×100=29.28 %

Answered By shekar