Do all materials burn ? in Combustion, Fuels and Flames – Class 8 Science Experiment

Chapter Name: Combustion, Fuels and Flames

Activity Name: Do all materials burn ? in Combustion, Fuels and Flames

Activity Description:

In this activity, we will investigate the colors produced by different metal salts when introduced into a flame. Each metal salt will emit a characteristic color when subjected to heat. We will observe and record these flame colors to understand the concept of flame emission spectroscopy.

Required Items:

1. Bunsen burner or a gas stove
2. Nichrome wire or a metal loop
3. Metal salts (e.g., sodium chloride, copper sulfate, potassium chloride, strontium nitrate, etc.)
4. Spirit lamp or a candle
5. Safety goggles
6. Laboratory apron

Step by Step Procedure:

1. Attach the metal loop or nichrome wire to a handle to create a simple loop holder.
2. Dip the metal loop into the spirit lamp or candle flame to clean it. This step removes any contaminants that might interfere with the color observations.
3. Take a small amount of one metal salt (e.g., sodium chloride) and coat the cleaned metal loop with it by dipping the loop into the salt sample.
4. Hold the metal loop in the hottest part of the Bunsen burner flame or the gas stove flame.
5. Observe the color of the flame produced and record it in a table along with the name of the metal salt.
6. Repeat steps 3 to 5 for each different metal salt, ensuring you clean the loop between tests to avoid cross-contamination.

Experiment Observations:

Metal Salt – Flame Color

1. Sodium chloride – Yellow
2. Copper sulfate – Green
3. Potassium chloride – Lilac
4. Strontium nitrate – Red

Note down your observations in table format:

Precautions:

• Wear safety goggles and a laboratory apron to protect your eyes and clothing from potential splashes or spills.
• Handle the metal loop carefully, as it will become hot during the experiment.
• Perform the experiment in a well-ventilated area to disperse any fumes.

Lesson Learnt from Experiment:

The experiment demonstrates that different metal salts produce characteristic flame colors due to the excitation and subsequent emission of electrons when heated. This phenomenon is the basis of flame emission spectroscopy, a valuable analytical technique used to identify the presence of specific elements in various compounds.