Объясните разницу между физическими и химическими превращениями на английском языке.
A chemical change is a change that takes place in a substance, during which it breaks up into simpler substances or it combines with other substances to make a new one with different properties or characteristics. For example, mercuric oxide may be changed to mercury and oxygen by heating it; the burning of wood is an example of a chemical change in which the elements carbon and oxygen are combined to form the gas, carbon dioxide. A physical change is one in which the identifying characteristics or properties of the substance are not changed although a change in form or state may occur. The melting of ice, the breaking of glass, or the dissolving of sugar in water are examples of physical changes.
Разделите следующие превращения на физические и химические.
1. Melting of ice. 2. Souring of milk. 3. Rusting. 4. Dissolving of sugar in water. 5. Separating the pigments of grass by chromatography. 6. Burning wood.
Test 3
1. Pottery, brick and porcelain with glass provide the class of materials known as…
a) non-metals
b) ceramics
c) metals
d) alloys
2. Ceramic materials are … in weight.
a) light
b) heavy
c) strong
d) durable
3. The … of application of products made from clay is very wide.
a) range
b) form
c) class
d) area
4. Silicate materials … glass, porcelain, enamels and cement.
a) form
b) use
c) consist of
d) include
5. The ceramic materials … from rock or clay mineral.
a) compound
b) were compounded
c) are compounded
d) have compounded
6. The ceramics … as building materials since ancient time.
a) have used
b) used
c) are used
d) have been used
7. Some ceramic materials can … steel.
a) form
b) cut
c) provide
d) cast
8. The making of steel depends on the … of ceramics
a) use
b) form
c) property
d) bond
9. The large oxygen atoms … as a matrix with small metal allows.
a) create
b) serve
c) influence
d) produce
10. Many articles made of ceramics provided man with …