Engineering MOSAIC. Мантатова С.С - 29 стр.

UNIT XXIII                                                              new element in some minerals but could not get it pure. The first
Tantalum                                                                chemist who got it in a comparatively pure state was Berzelius. But
Before you start                                                        even he failed. It was really his follower Henry Rose who finally got
1. Answer the following questions:                                      pure tantalum after he had studied its properties for almost fifteen
1. What rare metals do you know?                                        years. In fact, even now it is difficult to get pure tantalum.
2. Why are these metals important in metallurgy?                              What about the uses of this rare metal? Where is it applied? It
Vocabulary                                                              has important uses in medicine, to begin with. Surgeons fix up
2. Match the words from the text with the meanings (1-7) below:         fractured bones and skulls and unite tissues with it. They also use
a. withdraw           1. metal in the form of a thread                  tantalum to replace muscles. And they knit together sinews with fine
b. disrupt            2. similar cells and their products produced by   tantalum wire.
                      human beings                                            Doctors believe it possible to make use of tantalum in surgery
c. fracture           3. the branch of medicine                         because it does not irritate tissues. And it does not disrupt the
d. tissue             4. to bother                                      functions of the body either. Tantalum is both hard and flexible. As a
e. wire               5. to be broken                                   matter of fact, it is so flexible that it can be easily drawn out into the
f. surgery            6. to take away                                   finest wire. Tantalum resists corrosion. That is why it is fit for lining
g. irritate           7. to throw into disorder                         chemical apparatus. Besides, it has a most important use in
                                                                        metallurgy. It is good for making high-quality steels. Of course,
Reading                                                                 tantalum is still a rare and valuable metal, and so it cannot be used
3. Read the text and find answers to the questions below:               widely.
     1. Why is tantalum named after the hero of Greek mythology
       hero?                                                            Speaking and Writing
     2. Why is it difficult to get tantalum in a pure state?            4. Arrange the following sentences according to logic of the text:
     3. Where can tantalum be used?                                         1. Tantalum is very useful in metallurgy.
     4. What are the properties of tantalum?                                2. Tantalum is suitable for lining chemical devices.
                                                                            3. This chemical element was called after a hero of Greek
                              Tantalum                                         mythology.
                                                                            4. This metal doesn’t irritate tissues during surgical operations.
      First of all, where does the name of this metal come from? The
                                                                            5. It is very difficult to obtain pure tantalum even now.
metal, grey and hard, was named after Tantalus, a hero of Greek
mythology. Tantalus was the son of Zeus ['zju:s] and the nymph
                                                                        5. Read the text once more and fill in the table:
Pluto ['plu:tqu] and father of Niobe ["naI'qub]. Tantalus was
severely punished because he revealed the secret of Zeus. He was
plunged up to the chin in water with the fruit hanging over his head.            scope                 properties           purpose of using
But both water and fruit withdraw from him, whenever he tried to           medicine  flexibility unite tissues
reach for them.                                                          ……………………. …………………….. …………………….
      In the early nineteenth century Ekeberg, a Swedish scientist,      ……………………. …………………….. …………………….
suffered about as much as Tantalus himself when he discovered a