Antifreeze Water Lab

Effects of Antifreeze on the Boiling Point of Water Lab

Purpose: The purpose of this lab is to see how the boiling point is effected by adding antifreeze and to discover how this happens.

Brief Background: The concepts used in this lab are intermolecular forces, vapour pressure/vapour pressure reduction and boiling point elevation. Intermolecular forces are weak forces of attraction and repulsion between particles/molecules etc.. By adding the antifreeze, the intermolecular forces got stronger. Vapour pressure is the pressure that is directly above the surface of a liquid exerted by the molecules that have been evaporated. By adding the antifreeze, it interfered with the vaporization of the water therefore lowering the amount of evaporation that occurred which then lowered the vapour pressure. Boiling point elevation is the difference in temperature between the boiling point of a solution and the boiling point of the pure solvent

We added 10ml of antifreeze to the water and continued heating it until it boiled then recorded the temperature. We repeated that step until we used up all of the antifreeze. We recorded the temperature every time it boiled.

Observations: Our first observation was that when we added the first 10ml of antifreeze the solution stopped very briefly. When we added the second 10ml of antifreeze the solution stopped boiling for a few seconds then continued quite quickly. We added the next 10ml and the same thing happen the boiling stopped for a few seconds then continued. When adding the last two sets of 10ml, the boiling seemed to slow down and the temperature increased above the lines on the thermometer.

Data Table:

Amount of Antifreeze Temperature

0ml before heating 21°C

0ml Boiling Point 105°C

10ml