Saccharin

S accharin is an artificial 5_____. You've probably seen it in a pink package when you're out at a restaurant; it's the main component of Sweet & Low. This chemical has been highly criticized as a carcinogen or otherwise dangerous chemical, but 6____ this has not been shown. Constantin Fahlberg 7_____ saccharin in 1878 while working in the lab of Ira Remsen. While working on the chemistry of coal tar derivatives Fahlberg took a dinner break. Picking up and taking a bite of a roll he noticed that the roll was much sweeter than it should have been. Fahlberg realized that the sweetness must have come from his hands, which he hadn't washed since 8_____ in the lab. He dropped the roll and returned to the lab, tasting each chemical in his lab to find out which chemical was responsible for the 9_____. Fahlberg became very wealthy from his discovery, but Ira Remsen and the university Fahlberg was working for saw none of the benefits of this accidental discovery.

Mauveine

M auveine was an early mauve dye 10_____ for clothing. The discovery was made by William Henry Perkin in 1856. Perkin started his research career at the young age of 15 studying malaria in the lab of August Wilhelm von Hofmann. Perkin was 11_____ a way to synthesize the molecule quinine, a rather expensive natural product known to fight malaria. Instead of 12_____ malaria, though, Perkin ended up changing fashion forever. He discovered the reaction that transforms aniline into mauveine, a molecule with an intense purple color. Just as Fahlberg had hidden his saccharin discovery from his mentor, Perkin experimented on mauveine in private in his own lab. When he did patent his dye it made him rich.

Science can be messy. Sometimes the answer you get isn't the answer you were 13_____. Sometimes you get a result that leads to a discovery that is completely 14_____ to what you were researching in the first place. That's why it's important to stay alert; you never know where the next great discovery will come from.

1. A complete	B completely	C completed
2. A has returned	B had returned	C returned
3. A mold	B moldy	C moldiness
4. A led	B lead	C have led
5. A sweet	B sweeter	C sweetener
6. A scientifically	B science	C scientific
7. A discovering	B discovered	C had discovered
8. A to be	B been	C being
9. A sweeter	B sweetness	C sweet
10. A used	B using	C use
11. A looking at	B looking forward	C looking for
12. A cure	B curing	C cured
13. A expecting	B expected	C expect
14. A related	B relate	C unrelated

6. Watch the video ‘Are artificial sweeteners really safe?’ Decide if the statements are true (t) or false (f).

When artificial sweeteners were first released, scientists were finding links to various forms of life-threatening cancer! A lot has changed since then, but are they really safe? Laci takes a look at the top three most popular sweeteners to try to figure out which is the safest.

1. The first artificial sweetener was discovered while working on dyes from tar coal.
2. The FBI agrees that sucralose is a safe and not carcinogenic alternative to sugar.
3. The top three most popular sweeteners are saccharine, sucralose and aspartame.
4. The fact that aspartame causes cancer is absolutely proved by scientists.
5. Artificial sweeteners help to lose weight.
6. Stevia has a positive potential for human consumption.

7. Speak upon the following topics:

1. Organic chemistry as a science.

2. Synthetic organic chemistry as an applied science.

3. Organic chemistry and its role in our daily life.

4. Modern organic chemistry.

8 . Based on the text B and extra information prepare the mini-lecture “Classification of organic compounds having the biological importance” in MS Power Point. Use the following plan:

1. Carbohydrates.

2. Peptides and Proteins.

3. Lipids.

4. Nucleic Acids (DNA and RNA).

UNIT 5. PHYSICAL CHEMISTRY