Question

What is the unknown solute in a solution of benzophenone with using freezing point depression? In this lab, the test tube with the solution was put in a hot water bath on a hot plate. The test tube was in a beaker.

Mass of benzophenone: 6.863 g

Mass unknown: 0.752 g

I placed benzophenone in a test tube in the hot water bath. Once it melted, I recorded 48.5 C. I stirred the test tube and the temperature lowered to 46.2 C. I melted it again and recorded 48.5 C and continued to stir and it lowered to 46.7 C.

I added the unknown in the benzophenone. It was in the hot water bath until it melted. The melting point temperature is 36.2 C. I stirred the solution and the temperature rose to 40.2 C. I placed the solution back in the hot water bath until it melted. The temperature at the melting point was 37.0 C. I stirred it and it continued to rise to 40.4 C.

What is the solute added into the solution? What is the molality?

this experiment was done in my general chemistry 2 class. im just trying to get delta temperature so i can plug into the equations.

Answer 1

Unknown solute may be maltose.

Explanation is given in attached file
For the guven Experiment we have taken the different data for freezing punt de pression Experimenti- Heus wat af solute = 0.752gm. aut af, solvent wie benzophenone = 6.863 m. Melting point of benta prenore 48.5c. after, adding solute ut will become = 36.2°c, Depression of freezing point will be = (48-5 e - 36,2 c) = 12.3°C. using the formula we know that, • Tf = KfXm. mo malality of the solution. kg fors bento phenone = 9.8 12.3 = 9.8 xm 2 Ima 1:255) So, molality af solution is 1.255. PITO

No: 0.768X1000 MX 6.863 gm unknown lotion. Salute, Normal wt of 752 15x6.863 MX6 863 M= M = 87.309 / Molecular out of the salute = 8 7. i unknown solute may be maltose have malecular formula = Ca Harou]