Name ______

Date______

Period ____

Burning Sugar Lab

Background Information: Cane sugar is a kind of carbohydrate and is made of carbon, hydrogen, and oxygen. The chemical formula is C12H22O11. During this lab you will heat sugar in a test tube over a Bunsen burner flame. Heat energy from the Bunsen burner provides the energy, which causes atoms in the sugar molecule to vibrate faster and eventually break apart. The sugar is then chemically changed when these free atoms rearrange themselves, react with oxygen in the air and come back together to create new substances. The Law of Conservation of Mass states that mass is neither created nor destroyed. Therefore, the new products cannot contain any new atoms and should have the same mass as the atoms before the reaction.

In this lab we will find the mass of the sugar before it breaks apart and reacts with oxygen and find the mass of the substance in the test tube after the chemical reaction. How do you think the masses will compare? Hint: think about what products may form from this reaction. (C12H22O11+ 6O2 (Heat) ???)

Question:

Will the mass of the substance in the test tube (the sugar) remain the same, or change, after being heated with the Bunsen burner?

Hypothesis:

Materials:

Procedure:

  1. Complete all preparations and safety checks for Bunsen burner use.
  2. Place a sugar cube in the mortar and use the pestle to crush it into a powder.
  3. Spoon all the sugar onto the weigh boat so you can pour it into the testtube.
  4. Find mass of empty test tube and note mass in Data Table 1.
  5. Pour sugar into the test tube and find mass of sugar + test tube.
  6. Subtract mass of test tube to get mass of sugar and write in Data Table 1.
  7. Attach test tube holder to the top of the test tube.
  8. Put on safety equipment and light the Bunsen burner. The flame should be lower than normal, about 3 inches.
  9. HEAT TEST TUBE OVER HOTTEST PART OF FLAME. POINT IT AWAY FROM YOU OR ANYONE ELSE!
  10. Watch the sugar in the test tube VERY CAREFULLY! Make observations of all changes that occur during heating.
  11. REMOVE TEST TUBE FROM FLAME BEFORE SUBSTANCE CAN RISE AS HIGH AS THE TOP OF THE TUBE.
  12. Place test tube in the test tube rack and allow it to cool. Record your observations on your lab sheet as the test tube cools.
  13. Find the mass of the test tube with the newly created substance and note it on Table 1.
  14. Clean up your area.

Data Table 1: Mass of Reactant and Product REACTANT

(SUGAR)

Mass of sugar + test tube =______g - Mass of test tube = _____g = ______g

PRODUCT

Mass of new substance + test tube = ______g – test tube ______g = ______g

Mass of new substance (______g) is ______(<,>,=) mass of sugar (______g)

Data Table 2: Observations of New Substances (Products)

NAME 3 NEW SUBSTANCES THAT YOU THINK WERE FORMED

  1. ______2.______3. ______

CONCLUSION QUESTIONS: Answer the following on a separate sheet of paper.

  1. Name each substance that formed when the sugar was burned and reacted with oxygen in the air. Include the observation or description of that substance.
  2. Name the state of matter that the three substances occurred in. (Hint: One substance occurred in 2 states of matter)
  3. What caused the sugar cube to be able to change into other substances? (see background information)
  4. Why did the black substance rise up in the test tube? (Hint: it was full of a particular state of matter whose particles like to expand outward)
  5. Where did the water come from? Why did it change state?
  6. Where did the extra oxygen come from to create the carbon dioxide?
  7. How did the mass of the substance in the test tube that was formed after burning compare with the sugar in the test tube before burning?
  8. Explain why the mass of the substance in the test tube is not the same as the original mass of the sugar before burning. (Discuss how the sugar was chemically changed, what products formed, and what happened to those products. This should be a paragraph (5-8 sentences).