THINK TANK
 Question: What is the melting point of the ice?
 A.100 ° C B.40 ° C C. 0 ° C D. 2 ° C

Result A:

In this part, we tested the freezing point using the following method. We froze the salt solution get frozen by using the freezer. After the solution froze, we put it in a place with room temperature and waited until the frozen solution reached the solid-liquid stage. At this time we used an Infra-red Thermometer to test the freezing point of the salt solution(The temperature of salt solution at this stage is equal to the freezing point). We decided to use this way because if we froze the solutions until they reached the solid-liquid stage, it would be very hard to test all of the solution together(the time it would take for the solutions to freeze would vary.). This method would consume too much time. The method we used allowed us to test all of the solutions together and to save a lot of time.

 Number Chemical Freezing Point( ° C) Available Range( ° C) 1 CaCl2 -8 >-8 2 K2SO4 -4 >-4 3 (NH4)3PO4 -5 >-5 4 Na2HPO4 0.55 >0.55 5 (NH4)2SO4 -15 >-15 6 NaCl(Rock Salt) -11 >-11 7 NH4Cl -10 >-10 8 MgSO4 -3 >-3 9 CH3COONH4 -7 >-7 10 MgCl2 -10 >-10 11 KCl -11 >-11 12 Na2SO4 -1 >-1 13 CH3COONa -6.5 >-6.5 14 K2HPO4 -8.5 >-8.5 1 Water 0 0