Dong

=**Boiling Point of Mixture (Ethanol & Water)**=

__**Materials**__

 * Water
 * Ethanol
 * Hot Plate
 * Flask
 * 2 Stoppers (one with 2 holes / one with 1 hole)
 * Ice
 * 2 Beakers (Big and Small)
 * Test Tube
 * Graduated Cylinder
 * Crucible
 * Tube
 * Clamp
 * Forceps
 * Matches
 * Stand
 * Digital Balance
 * Stopwatch
 * Computer
 * Lab Pro Sensor (Temperature Probe)

__**Variables**__
o Water + Ethanol
 * Mixtures

__**Procedure**__


Part A: 1. Mix 35mL of pure ethanol in 65mL of water (total: 100mL): 35% concentration 2. Pour the mixture in the flask 3. Put a 1-hole-stopper on the opening of the flask 4. Put the temperature probe through one hole of the stopper in step 3 5. Connect the probe to the sensor and to the computer 6. Put the tube through the other hole of the stopper in step 3 7. Prepare a beaker filled with ice 8. Put the test tube in the ice 9. Put a 1-hole-stopper on the opening of the test tube 10. Put a tube through the hole of stopper in the step 9 11. Heat the water / mixture 12. Record the temperature of water / mixture over time on the computer using the sensor 13. Record the temperature of water / mixture that remains constant (boiling point) Part B: 1. Take the distillation of liquid gathered in the test tube and pour into a crucible 2. Measure the mass and volume of liquid using digital balance 3. Burn the liquid using the match 4. Measure the mass and volume of liquid left after burning and calculate the density 5. Use the data of step 4 to calculate the mass, volume, and density of liquid that burned away

__**Hypothesis**__
Part A: I expect the temperature of mixture would stop and remain constant at about 85 C, because ethanol has lower boiling point than water does. Therefore, when alcohol and water are mixed together, it would have the boiling point which would be between water’s and ethanol's boiling point. The more I add alcohol to water the more the boiling point would be closer to that of ethanol.

Part B: I expect the liquid distilled from Part A to have a density of pure Ethanol (0.789g/mL). It will be because ethanol will be vaporized first with its lower boiling point.

Part A:
When boiling the mixture, it seemed to remain constant temperature at 85 C. When the temperature remains constant, it would mean that the boiling point has reached. Compared to pure water boils at 100 C, the mixture boiled at 85 C. According to my research, ethanol boils at 78.4 C. Since the 35% concentrated mixture decreased the boiling temperature by 15 C, higher concentration of mixture would further decrease the boiling temperature.

__Relationship Between Concentration of Mixture and Boiling Point__



Part B:
Liquid Distilled out From Part A:
 * Volume (mL) || Mass (g) || Density (g/mL) ||
 * 34.3 || 28.64 || 0.835g/mL ||

Experiment of Crucible;
 * Liquid || Volume (mL) || Mass (g) || Density (g/mL) ||
 * Original Liquid || 2.5 || 2.25 || 0.9 ||
 * Liquid Remained After Burning || 1.2 || 1.06 || 0.88 ||
 * Liquid Burned (estimated) || 1.3 || 1.19 || 0.91 ||

//__According to the Simple Theory__//

 * The liquid distilled out from Part A should have a density of pure Ethanol, which is 0.789g/mL. It would be because the ethanol which has lowe boiling point would vaporize faster than water. Therefore, only the pure ethanol would have been gathered through ditillation.


 * If the theory above didn't work, the liquid reainedurned in the crucible should have the density of water, which is 1g/mL. Moreover, the expected density of liquid burned should have been that of ethanol (0.789g/mL).

__Science Behind the Experiment__
Ethanol and water mixed together is a homogeneous mixture. It is not chemically blended but rather physically. Therefore, the solution can be seperated through distillation. However, if the mixture was chemically blended, it would have only been seperated by chemical reaction. According to my reserch, ethanol has a lower boiling point (78.4 C) than that of water (100 C). It's because ethanol has a lower intermolecular forces than water does, which is the forces holding molecules together. Therefore, when water and ethanol mix together, boiling point would get lower than 100 C.

__Evaluation__
For Part A, in determining the relationship between concentration of ethanol boiling point, there were two points to make more accurate result. Therefore, if I can do this experiment again next time, I would try an experiment with more various concentration of ethanol.

For Part B, the result of density of burned and remained liquid was not consistent over several trials. Therefore, if I can do this experiment again next time, I would try to use as little amount of liquid as possible (because it helps to improve the precision). Moreover, since solution was well mixed, I think there would have remained some ethanol that didn't burned. Therefore, next time, I can make the liquid sit there for few minutes, and then do the burning.

__**Resources**__
http://www.siraze.net/chemistry/sezennur/subjects/experiment/004.pdf (source of experiment idea) http://www.chem.purdue.edu/gchelp/liquids/boil.html (Science behind the experiment) http://www.science.uwaterloo.ca/~cchieh/cact/c123/intermol.html (Science behind the experiment)

=//Additional Information//=

__Ethanol__
  __Other names __: Ethyl alcohol; grain alcohol; pure alcohol; hydroxyethane; drinking alcohol; ethyl hydrate __Molecular formula __: C2H6O __Molar mass __: 46.06844(232) g/mol __Appearance __: colorless clear liquid __Density __: 0.789 g/mL __Melting point __: −114.3 °C (158.8 K) __Boiling point __: 78.4 °C, 173.1 F (351.6 K) __<span style="font-size: 11pt; color: rgb(51,51,51); font-family: Arial;">Solubility in water __<span style="font-size: 11pt; color: rgb(51,51,51); font-family: Arial;">: Fully miscible http://en.wikipedia.org/wiki/Ethanol



At the boiling point, saturated vapor pressure equals atmospheric pressure
http://hyperphysics.phy-astr.gsu.edu/Hbase/Kinetic/vappre.html

http://cache.eb.com/eb/image?id=72150&rendTypeId=35

Plan and Material List

Revised Plan and Material List

Observation

Graph