Chemistry Honors
Formation of Acetylene
Materials:
Forceps
Tap water
Calcium Carbide
Wooden splints
Water bath
Test tubes (4)
Test tube holder
Procedure:
A. Using a graduated cylinder find the volume of C2 H2 that will form in
each tube and record your answer in liters.
1. Invert a test tube full of water into a water bath half-full with water.
2. Use forceps to place a few small pieces of calcium carbide into the
beaker. Observe the bubbles rising from the calcium carbide CaC2.
These bubbles are acetylene gas C2 H2 (Very Flammable!!!!)
3. Place the inverted test tube over the calcium carbide and let the
acetylene gas completely fill the test tube.
4. Remove the test tube from the water and place a cork in it and place
it mouth down in the test-tube rack.
5. Repeat step three, three more times with the three other test tubes
collecting (a) one –half, (b) one-third, (c) and one-twelfth of a test
tube of acetylene respectively. Lift each tube from the water, always
keeping them inverted. Allow air to replace the water that runs out of
the test tube then cork the tube and place in the rack.
6. One at a time, uncork a tube (starting with the first one collected to
the last) and keeping the tube inverted place your thumb over the end
of the tube. Shake the tube vigorously for 20 to 30 times to mix the
air and acetylene. Hold the tube horizontally and bring a burning
splint close to its mouth. Wait until each reaction is complete.
Observe each test-tube carefully and make diagrams of what you
observe.
Analysis:
1. Name the types of chemical reactions that occurred.
2. What observations did you make concerning the four tubes?
3. In which test tubes did incomplete combustion occur?
4. Write a complete reaction equation. C2H2 + O2
5. Write an incomplete reaction equation. C2H2 + O2
6. How is this unbalanced equation related to the lab?
C2H2 + O2
C + CO + CO2 + H2O
7. Predict and balance this equation CaC2 + H2O
8. Predict and balance this equation C2H2 + O2
9. How much C2H2 is produced from 10g of CaO produced?
10. How much solid carbon was produced in tubes 1,2,and 3?