Hydrogen Bonding

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Amena Haidar
SCH4U
03/04/13

Hydrogen Bonding

Purpose:
The purpose of this investigation is to test the concept of hydrogen bonding.

Hypothesis:
Given the concept of hydrogen bonding I predict that the bulky glycerol molecules limits the number of possible hydrogen bonds. If water is mixed with glycerol should make it possible for water to form many hydrogen bonds with the glycerol molecules, causing it to become a exothermic reaction. Because glycerol has more possibilities for hydrogen bonding I believe that it will have the most energy change.

Materials:
-Lab apron-Safety glasses -250 ml beaker
-Tap water-Ethanol -Glycerol
-10 ml graduated cylinder - Two Styrofoam cups
-Paper lid for cups -Thermometer

Procedure:
Refer to lab sheet.

Observations:
| Volume (mL) | Ti(c) | Tf(C) | T |
Ethanol | 10 | 26 | 30 | 4 |
Water | 10 | 26 | 30 | 4 |
Glycerol | 10 | 26 | 27 | 1 |
Water | 10 | 26 | 27 | 1 |

Questions:
1. How do your observations support your hypothesis? Where you correct or incorrect? Why? Given my hypothesis I was incorrect, the Ethanol proved to have more of an energy change than the glycerol. n ethanol a hydrogen bond is formed between the oxygen of ethanol and one H-atom of water. The +I effect transfers the electronegativity towards the H- of -OH group.

2. Explain why the temperature increases in each case and explain why it increased more with one chemical than the other. The increase of temperature was a result of the hydrogen bonding between the elements. Hydrogen bonding consists of the attraction of hydrogen atoms bonded to N, O or F atoms in adjacent molecules. Depending on the possibilities of hydrogen bonding and the solubility of the solution changes the energy transfer between elements. 3. Draw the structural diagram of water, ethanol and glycerol.
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