Maria RodriguezPd. 7 Chemisty

Acetylene Gas (Ethyne)

Purpose: To produce and test acetylene gas in the lab and to find when acetylene gas becomes dangerous gas.

Directions: Fill five small test tubes with water and invert them in a large beaker half filled with water. Drop small lumps of calcium carbide (CaC2), one at a time into the water, and then fill the tubes with

different amounts of acetylene gas (full, 34

, 12

, 14

, and 1 cm) by using the water displacement method.

After the reaction, test the solution with red and blue litmus paper. Test each test tube with a flaming split test! CAUTION: USE GOGGLES!

Data:

Trial Amount of Gas Splint Test Results Combustion Type 1 Full Clear, nothing Incomplete2 ¾ Black Complete3 ½ Contain Fire Incomplete 4 ¼ Contain Fire Incomplete5 1 cm Black Complete

Solution Before CaC2 Solution After CaC2Color Clear Cloudy, GrayishOdor No Odor Oniony, FoulOther Stayed Red- Acid. Turned Blue- Base.

Questions:

1. What is the balanced reaction that has occurred? CaC2 + H 2O -----> C2H 2+ Ca(OH )2

2. What compound of calcium remains in the solution?Calcium carbide

3. What do you judge about the solubility of acetylene gas in water? Saturated

4. What is the deposit remaining in and on the test tube after the flame test? There was ash and black residue.

5. Why does the deposit form in some trials and not in others?The levels of gas varied.

6. Explain why a special burner is required for the complete combustion of acetylene gas in acetylene torches used by welders. The temperature needs to be elevated a lot higher than normal.

7. Write a balanced equation for the complete combustion of acetylene.

Maria RodriguezPd. 7 Chemisty

CaC2 +2 H 2O -----> C2H 2+ Ca(OH )28. Based in the reaction above in #8, how many moles of oxygen and or air would be needed to

burn one mole of acetylene? Oxygen= ____moles Air=____moles

9. Which test gave the loudest pop?None.

10. Based on the lab results, explain when acetylene gas can become a dangerous gas. It can become dangerous when handled in large numbers.

Evidence:

The types of combustion and the amount of gas in the test tubes, correlated directly. The more gas the more incomplete the combustion. The less the gas and the more complete the reaction.

Source of Error:

Man-made Error: We could have gotten the wrong amounts of gas wrong in the test tubes Systematic Error: The amount of calcium carbide could have been incorrect. Man-made Error: We could have lost the order of the test tubes and recorded the wrong the

wrong data for each test tube.

Conclusion:

The purpose of this experiment which was to find out when acetylene gas becomes dangerous and that purpose was fulfilled. The experiment determined that the amount of gas in the test tube correlated directly to the type of combustion that it would be. The less gas the more complete the solution. It left black residue in the test tube because it had fully combusted.