Introduction

The purpose of this lab is to become familiar with how to use the ChemLab program for determining mass using both the centigram balance and the electronic balance.

Using the centigram balance, the mass, in grams, of a copper slug will be determined by both direct weighing and weighing by difference techniques. Using an electronic balance, the wight of a copper slug will be determined by also utilizing direct weighing and weighing by difference. Average mass of a copper slug will be calculated using five (5) copper slugs and an electronic balance. Lastly, the mass of two unknown weights will be determined using the electronic balance and the weighing by difference technique.

The mass of a cooper slug can be determined accurately by both direct weighing technique and by weighing by difference. Using the electronic balance, the mass was more accurate at 2.966g versus the centigram balance which determined the mass to be 2.97g. The reason for this is that the electronic balance can determine mass to three decimal places, while the centigram balance can only determine mass to two decimal places. With the beaker weighing 50.000g, the weighing by difference technique was determined using the formula of 50.000(x)-50.000 = x with x representing the mass of the copper slug. The mass of the two unknown weights were determined in the same way, with weight #1 having a mass of 24.823g and weight #2 having a mass of 25.167g. The average mass of a copper slug using five different copper slugs was determined by first weighing all five slugs which resulted in a mass of 14.934g, and then dividing this number by the number of slugs included, which in this case was five. The average mass found was 2.9868g.

Procedure

This experiment was done using a total of six copper slugs of various weights (one in the first series of experiments, and 5 different copper slugs in the average mass experiment), 2 unknown weights, a 100ml beaker, two centigram