What Is It?

Physical Properties: What is it?

September 8, 2011

Identifying Physical Properties

Introduction

Scientists often identify unknown substances by their physical properties. Physical properties include boiling point, melting point, density and solubility. When given an unknown substance, and asked to identify it, the best way is to compare physical properties with known substances. In this experiment, a liquid and a solid unknown were to be identified by comparing their physical properties with a list of known compounds provided. To show that the density of a substance is dependent on temperature, the density of hot, cold, and room temperature water, and ice are to be recorded. An additional experiment was conducted to provide the density of 2-propanol. If the physical properties of the unknown substances are similar to the known compounds provided, then the unknown substances will be identified.

Experimental

The equipment needed:

Scale

Mel-temp

Capillary tube

Bunsen burner

Thermometer

Beaker(s)

Test tube

Graduated cylinder(s)

Stand

Unknown liquid

Unknown solid

Water

2-propanol

Ice

The first part of the experiment is to graphically determine the density of 2-propanol by measuring mass and volume of four different amounts. A graduated cylinder is placed upon the scale, and the scale is “zeroed out.” Then, 2 milliliters of 2-propanol is poured into the graduated cylinder, and the mass is recorded. The volume is already given, being 2 milliliters. Then, another milliliter of 2-propanol is added and the mass is recorded. This is done until the volume has reached 5 milliliters of 2-propanol. The data is then recorded onto a graph to calculate the density of 2-propanol.

The second part of the experiment is to determine the density of water at three different temperatures, as well as ice. A graduated cylinder is placed on a scale and “zeroed out.” 10 milliliters of cold water is poured into the graduated cylinder and the mass is recorded....