Question

Does anyone have an experiment with melting point and boiling point?​

Answer 1

Answer:

Introduction

We studied density and freezing-melting point in detail as characteristic properties of matter. Another such identifying property is the boiling point of a substance. The boiling point of a substance is the temperature at which it changes from a liquid to a gas (boiling) or vice versa from a gas to a liquid (condensing). Just as the change in state from solid to liquid requires heat, so does the change from liquid to gas. The heat, however, does not change the temperature of the substance. Instead, the heat is used exclusively to boil the substance that for the most part remains at a constant temperature throughout the boiling process. Once all the substance is boiled, the heat again raises the temperature of the now gaseous substance.

The boiling point of water is well-known to you; it is 212 degrees F and 100 Celsius.

In this experiment, you will measure the boiling point of two unknown liquids. (If you really care, the mystery fluids are water and isopropyl alcohol). The two liquids have different boiling points, both well above room temperature. At room temperature, both substances are liquids.

Procedure

I will give you some 10 or 20 ml of water or alcohol. Recall that characteristic properties are independent of the amount of the substance being measured. You will measure the boiling point of your substance and produce a graph of temperature versus time.

Build the contraption on page 46 of your book. Make sure the thermometer is sitting in the middle of the water and not touching the bottom of the tube. There will be a sample to look at in class.

Clamp the test tube with your fluid above a heat-spreading screen.

Make sure to add a few chips of porcelain to the bottom of the tube. This helps keep the temperature uniform and prevent uneven boiling.

Ask me to light your burner.

Every 30 seconds, read the temperature of the liquid.

Graph the temperature of the liquid versus time.

Wait and keep measuring every 30 seconds until the substance has been boiling for 5 minutes.