Full version Combustion Of Ethene

Combustion Of Ethene

This print version free essay Combustion Of Ethene.

Category: Science

Autor: reviewessays 13 February 2011

Words: 893 | Pages: 4

Combustion of Hydrocarbons

Purpose:

To practice collecting a gas by displacement, as well as to examine the products of complete, as well as incomplete combustion of acetylene gas.

Materials:

-Bunsen burner

-600mL beaker

-3 (18 x 150 mm) test tubes

-Calcium Carbide (CaC2)

-Water

-Apron

-Safety Glasses

-Test tube holder

-Spark lighter

-Wooden splint

-Grease pencil

-Ruler

Method:

1. The 600mL beaker was half filled with tap water, and the first test tube was filled with tap water, sealed with a piece of paper, and inserted into the beaker.

2. One rock of CaC2 was place in the beaker, and the test tube was placed on top of the reacting rock.

3. Acetylene gas was collected, filling the entire test tube, and then was removed from the beaker.

4. The Bunsen burner was then lit, and the splint was lit with the Bunsen burner.

5. The open end of the test tube was place next to the flaming splint, until the acetylene gas was lit.

6. With a ruler and grease pencil, half way up the second test tube was marked.

7. The second test tube was filled with tap water, sealed with paper, and then placed in the water.

8. One rock of CaC2 was then placed in the water, and the second tube placed on top of the reacting rock, until the gas reached the half way mark.

9. Acetylene gas was collected, and then the test tube was removed, and was placed on its top, allowing the acetylene gas and oxygen within the test tube to mix.

10. Steps 4 and 5 were repeated with the second test tube.

11. With a ruler and grease pencil, the third test tube was marked 1/10 from the bottom of the test tube.

12. One rock of CaC2 was placed in the water in the beaker, and the test tube was placed on top of the reacting rock, until the gas reached the line.

13. Acetylene gas was collected, and then the test tube was removed, and was placed on its top, allowing the acetylene gas and oxygen within the test tube to mix.

14. Steps 4 and 5 were repeated with the third test tube.

Observations:

Test Tube 1(Full of acetylene) Test Tube 2(1/2 Full of acetylene) Test Tube 3(1/10 full of acetylene)

Trial 1-Acetylene gas burned at the open end of test tube.-Flame did not move into test tube.-Slow, constant reaction-Carbon residue formed on end of test tube.-Small amount of liquid formed in test tube. Trial 1-Acetylene gas lit quicker than test tube 1.-The flame traveled into the test tube.-Quicker reaction than test tube 1.-Flame quickly died once the flame moved into the tube.-Carbon residue formed on the end, as well as within the test tube.-Small amount of liquid formed in test tube. Trial 1-No reaction

Trial 2-No reaction.

Trial 3-No reaction.

Trial 4-No reaction.

Trail 5-Acetylene gas lit much quicker than both test tubes 1 and 2.-The flame traveled into the test tube much faster than test tube 2, creating a whistle sound.-Flame disappeared quickly once it moved into the tube.-No carbon residue was formed on any part of the tube.-Small amount of liquid formed within the tube.

Analysis:

The acetylene gas lit and burned the longest in test tube once, likely due to the higher volume of the gas within the tube. The second test tube had a reaction that was similar to the first test tube when it was lit, because the flame burned like a candle on the end of the tube for a few seconds, but then quickly traveled into the tube burning the remaining acetylene gas. The acetylene gas in the third test tube did not burn on the end of the tube, but was quickly consumed as soon as it was lit; a much quicker reaction then both of the previous test tubes.

Conclusions:

In the first test tube, the volume of acetylene gas was the greatest, and there was no oxygen gas present within the tube. This explains why the reaction was slow, and the flame did not travel into the tube, because oxygen must be present for combustion to occur. Because carbon residue was formed, this reaction was incomplete combustion. The second tube containing Ð… acetylene gas was a quicker reaction because there was a presence of oxygen within the test tube, which also explains why the flame moved into the tube. Because carbon residue was formed, this reaction was incomplete combustion as well. The third tube, containing 1/10 acetylene gas was a much quicker reaction due to the fact that there was a much higher volume of oxygen, allowing for fast, complete combustion.

There are many sources for error when collecting gas by displacement in a test tube. Some of these, which explains why there were 5 trials in the third test tube, include air bubbles in the test tube while collecting the gas, not allowing the acetylene gas to mix with the oxygen in the tube, as well as collecting the incorrect volume of gas.

Chemical Reactions:

Tube 1

2 C2H2 (g) + 3 O2 (g) ® CO2 (g) + 2 H2O (l) + 2 CO (g) + C (s)

Acetylene gas + Oxygen ® Carbon Dioxide + Water + Carbon Monoxide + Carbon

Tube 2

2 C2H2 (g) + 3 O2 (g) ® CO2 (g) + 2 H2O (l) + 2 CO (g) + C (s)

Acetylene gas + Oxygen ® Carbon Dioxide + Water + Carbon Monoxide + Carbon

Tube 3

2 C2H2 (g) + 5 O2 (g) ® 4 CO2 (g) + 2 H2O (l)

Acetylene gas + Oxygen ® Carbon Dioxide + Water