The purpose of this experiment is to determine the freezing points of water, 10% antifreeze, and 20% antifreeze utilizing an ice bath and a really cool thermometer. Apparatus
Preparing the Ice Bath
1. Fill the tub ¾ full with ice.
2. Cover the ice with a respectable amount of salt.
3. Add water and stir that bad boy, the water should be standard temperature in a fwe minutes. Fill the test tube with any amount of water and submerge promptly *Check the test tube every few seconds until frozen. Record temperature. Repeat with both antifreeze solutions
| Freezing Point (°C)|
Distilled Water| 0.0°C|
10% Antifreeze| -3.5°C|
20% Antifreeze| -8.0°C|
1. Using the equation ΔT = Kf m, calculate the molality of the 10% antifreeze solution.
2. Use the formula molality = moles solute/kg solvent to find the number of moles in 10% antifreeze solution.
3. Using the formula molar mass = grams/moles calculate the molecular mass of antifreeze in the 10% solution.
4. Using the equation ΔT = Kf m¸calculate the molality of the 20% antifreeze solution.
5. Use the formula molality = moles solute/kg solvent to find the number of moles in 20% antifreeze solution.
6. Using the formula molar mass = grams/moles calculate the molecular mass of antifreeze in the 20% solution.
7. Average the molar masses you calculated in questions 3 and 6.
8. The formula for antifreeze is C2H6O2. Calculate its molarmass using the periodic table.
9. Calculate your percent error.
This lab was a phenomenal success! The purpose of determining the freezing points of water, 10% antifreeze, and 20% antifreeze was not only accomplished, but also done so in a splendid manner. The net figures of our experiment were less than 5°C off from the established values.
Of course, it goes without saying that this lab...