Shenzhen University Physical Chemistry Experiment Report

Experimenter: Zhang Zike, Liu Kaixin Experimental time: 2000/4/3

Temperature: 21.6 °C Atmospheric pressure: 101.1 kPa

Experiment 7: Mapping of the liquid phase diagram of two-component jujube

I. Purpose requirements

1) Analytical method for mapping lead-tin binary metal phase diagram to understand the basic characteristics of solid-liquid phase diagram

2), learn thermocouple production, calibration and temperature measurement technology

3) Master the use of automatic balance recorder

2. Instrument reagents

3. Experimental data and processing

Thermocouple working curve

Pb～Sn phase diagram

Questioning

1. What are the factors related to the slope of each step of the step cold curve and the length of the horizontal section?

A: For the slope, it is related to the paper speed of the balance recorder and the ratio of the substances in the mixture; for the horizontal length, it is related to the control of the cooling rate.

2. According to the experimental results, it is discussed whether the cooling rate control of each step of the cold curve is proper.

A: In this experiment, we did not take cooling control, but the platforms are obvious, so from this point of view, we operate properly!

3. Is it feasible to draw a phase diagram using differential thermal analysis or differential scanning?

Answer: Because the sample changes more in the endothermic heat, the heat capacity changes greatly, and the reference material is far from the reference, causing the baseline to drift. Therefore, the above two methods are not feasible.

4. Try to compare the similarities and differences of the gas-liquid phase diagrams from the experimental method.

A: The difference: the way to determine the coordinates is different.

The same point: both determine the relationship between temperature and concentration, the data of both are the result of thermodynamic equilibrium.