Question

Synthesis of zinc iodide

How well do your results agree with the law of conservation of Mass ( use percent difference to compare)

% composition of Zn and I:

Convert mass Zn to moles

Convert mass I2 reacted to moles

Using the molar ratios determine the emperical formula for zinc iodide

Given:

Mass of empty test tube#1: 22.28g

Mass of test tube #2 + boiling stones: 23.10g

Zn reactant:

Mass of tube #1 + Zn + Iz: 26.33g

Mass of I2: 2.06

Zn

Mass of test tube#1 + remaining Zn: 23.78g

Mass of Zn consumed in the reaction 0.49g

Zinc iodide

Mass of test tube#2+ zinc iodide: 25.64

Mass of Zinc iodide:0.69

Answer 1

Mass of iodine = 2.06
Molar mass of iodine = 253.8 g/mol
Number of moles of iodine
Mass of Zn reactant
Molar mass of Zn = 65.4 g/mol
Moles of Zn moles
Mass of Zn consumed in the reaction = 0.49 g
Moles of Zn consumed in the reaction
Thus 0.00749 moles of Zn are consumed and 0.008116 moles of iodine are consumed.
Hence, the ratio of the number of moles of Zn consumed to the number of moles of iodine consumed is 1:1.
The empirical formula is
Mass of Zn remaining unreacted
Mass of zinc iodide formed
Total mass of reactants before reaction = mass of iodine + mass of zinc
Total mass after reaction = mass of zin unreacted + mass of zinc iodide formed
Thus, total mass of reactants before reaction is equal to the total mass after reaction.
Hence, the results agree with the law of conservation of mass.
The percentage difference between total mass of reactants before reaction and the total mass after reaction
% which is very small.