Chemical Formulas

2 Pages 526 Words

Chemical Formulas


Objective

The object of this lab was to help show how chemical formulas explain the displacement of chlorine in the reaction. Also, the purpose was to find and understand empirical formulas, and how to find the empirical formula for ZnCl2.

Procedure

First, obtain the necessary materials and set them up on a clean bench. Place the ring stand above the Bunsen burner, and clean the evaporating dish by putting it on the ring stand. After allowing the evaporating dish to sit above the Bunsen burned for five minutes, carefully remove and measure the mass of the evaporating dish, and record. Next, set up a steam bath by filling about half of a 250 mL beaker and setting on a hot plate. While this is heating, add .5 grams of granular Zinc to the clean evaporating dish. Once the water is boiling, place the evaporating dish over the beaker and add about 15 mL of HCl. It is very important to make sure that the evaporating dish fits on top of the beaker without falling in. Once the Zinc evaporates, allow the evaporating dish to cool. Once it cools, measure the mass of the Zinc Chloride three times and record.

Data

Weight of evaporating dish and Zinc 76.65 g
Weight of evaporating dish 76.11 g
Weight of Zinc .5400 g
Weight of evaporating dish and Zinc Chloride
First Weighing 77.58 g
Second Weighing 77.60 g
Third Weighing 77.61 g
Weight of Zinc Chloride 1.48 g
Weight of Chlorine in Zinc Chloride .940 g
Empirical formula for Zinc Chloride ZnCl3

Questions

1) If you have the weight of the substance, you can figure out its molecular formula. If you do not have the weight, you cannot find the molecular formula.

2) ZnCl2 ~ 1Zn + 2Cl =136.28 (see calculations)

3) Can you determine atomic weight of zinc by the methods used in this experiment? What additional info is needed to do this? No, because y...