1. What is the main topic of the lecture?

A. A method of packing coffee at high pressure and temperature

B. A method of decaffeinating coffee while preserving its flavor

C. Reasons why carbon dioxide is added to caffeinated soft drinks 

D. The critical importance of carbon dioxide for the food industry


2. How does the professor organize the review of the phase diagram?

A. By using an example of water vapor gradually changing to solid ice

B. By showing phase changes that occur when pressure and temperature increase at the same time

C. By first showing temperature-induced phase changes and then showing pressure-induced phase changes 

D. By first explaining the properties of gas and then introducing the properties of supercritical fluids


3. Under what conditions do supercritical fluids form? 

A. When a solid begins turning into a liquid

B. When a very hot gas is put under high pressure

C. When certain solids dissolve in certain liquids

D. When a liquid is al low temperature but under high pressure


4. What two properties of supercritical fluids does the professor mention? Click on 2 answers

A. They can permeate solids

B. They dissolve other substances

C. They diffuse very slowly, just as liquids do

D. They have low densities at high pressures.


5. The professor describes a process of caffeine extraction from coffee beans using carbon dioxide (CO2) Put the steps of the process in the correct order

Click on a sentence Then drag it to the space where it belongs. The first one is done for you.


Supercritical CO2 is led into a high-pressure chamber









Answer Choices

A. Caffeine crystallizes

B. CO2 permeates the beans

C. The pressure is decreased

D. Caffeine dissolves


6.What does the professor imply when he says this:

A. The process of caffeine extraction is less complicated than it sounds 

B. More research needs to be done on supercritical fluids

C. He will explain what a supercritical fluid is to the class

D. Will not spend much time reviewing supercritical fluids



电子邮件地址不会被公开。 必填项已用*标注