2.3.1 - Laboratory Activity : Comparing the Properties between Alkane and Alkene in terms of their Combustion Flame

Laboratory Activity 2.3.1: Comparing the Properties between Alkane and Alkene in terms of their Combustion Flame

Aim: To study the difference in properties between alkane and alkene in terms of their combustion flame
Problem statement: Are the properties of alkenes is similar to alkanes?
Hypothesis: The alkene flame will produce more soot than the alkane.
Variable:

	»	Fixed variable : The quantity of alkane and alkene used
	»	Manipulated variable : Type of alkane and its corresponding alkene
	»	Responding variable : Sootiness of the flame produce

Material: » Hexane » Hexene

Apparatus: » Splinter » Crucible » Filter paper » Measuring cylinder

Procedure:

►

1. Each crucible is filled with 2cm3 of hexane and 2cm3 of hexene. 2. Lighted splinter is used to light up the contents in each crucible. 3. Colour and sootiness of the flames are observed. 4. A piece of filter paper is placed about 3 cm above each flame for 5 seconds. 5. The amount of soot formed on both filter papers are compared.

Observation:

►

Observation With hexane With hexene Burning in the air Yellowish sooty flame Yellow and a very sooty flame Exposed filter paper

Analysis:

	►	Both hexane and hexene burnt in the air with yellowish flame with hexene producing more soot compare to hexane. This is because the percentage of carbon by mass of hexane is higher than the percentage of carbon by mass of hexene.
	►	Percentage of carbon by mass of hexane, C6H14 $\text{=}\frac{72}{86}\mathrm{\times }100\text{\%}$

= 83.7%

►
Percentage of carbon mass of hexene, C₆H₁₂
$\text{=}\frac{72}{84}\mathrm{\times }100\text{\%}$

= 85.7% Conclusion:

►

The combustion flame of alkenes produces more soot than the alkane.

⇲ For exercise(objective and subjective), download for free on Android OS.