Exercise 8.

a)Grammar and spelling quiz: find and correct the mistakes.

1. Bismuth used id make low-melting-point casting aloys.

2. This aloys from solidificataon gived cler replicataon with intricate features expands.

3. The metal extracts by carbon reduction of her oxide.

4. What you knows to alkaline-earth metals ?

5. Alakaly metals reacting in water.

6. What is an difference among lead and bismuth ?

7. Junin were the first which discovered ths difference.

8. We want describing the properties of this element.

b)Chemical quiz: Are these sentences true or false ?

1. Bismuth is an acid.

2. Beryllium is an alkali metal.

3. Bismuth compounds (when lead-free) are used for cosmetics and medical preparations.

4. Bismuth has a high electrical resistance and a high Hall effect when placed in magnetic field.

5. Bismuth is used to make low-melting-point casting alloys with hydrogen and oxygen.

6. Graphite is used to make electrical contacts.

7. Diamond is used to produce solid lubricants.

8. Carbon is an essential element for all living organisms.

c)Compare bismuth with iron and tin on the following scheme, using comparative and superlative degrees:

e.g. The boiling point of iron is higher than that of bismuth.

1. Melting point;

2. Boiling point;

3. Relative atomic mass;

4. Which of these metals is more ductile?;

5. Which of these elements is widely-used?;

d)Make the following sentences interrogative and negative:

1. These alloys expand on solidification to give clear replication of intricate features.

2. The metal is extracted by carbon reduction of its oxide.

3. Bismuth compounds (when lead-free) are used for cosmetics and medical preparations.

4. The metal has a high electrical resistance.

Texts for educational purposes

<== попередня сторінка	\|	наступна сторінка ==>
Bismuth	\|	Lead and its compounds

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