Fill in the blanks:
1. ........................ is hydrated ferric oxide.
2. ........................ is used for galvanising iron.
3. We get ........................ by the process of crystallisation.
4. A chemical change is usually ........................ and permanent.
5. All chemical changes involve ........................ or ........................ of energy.

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Solution

1. Rust is hydrated ferric oxide.
2. Zinc is used for galvanising iron.
3. We get pure substances by the process of crystallisation.
4. A chemical change is usually irreversible and permanent.
5. All chemical changes involve absorption or liberation of energy.

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Similar questions

Q. Assertion :Zinc is used for galvanising iron. Reason: Rust is hydrated ferric oxide.

_________ is defined as a process where materials, usually metals, deteriorate as a result of a chemical reaction with air, moisture, chemical, etc. For example, iron, in the presence of moisture, reacts with oxygen to form hydrated iron oxide.

Q. Properties of physical and chemical changes are given below. Sort the properties of physical and chemical changes in the correct column.

1. New substances are formed.
2. Precipitation is an example of this.
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4. Composition of substance remains same.
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Physical change	Chemical change
1. 2. 3. 4.	5. 6. 7. 8.

Question 15

Fill in the blanks in the following statements using the words given in the box

(a) Making sugar solution is a …………………. change
(b) A physical change is generally ……………………..
(c) Grinding of wheat grain changes its size. It is a …………….. change.
(d) Iron benches kept in lawns and gardens get ……………… it is a …………….
(e) change because a new ……………… is formed

Q. Following are the observations of changes that have taken place. Classify them into chemical change or a physical change. [5 MARKS]

1. The change is temporary and can be reversed by changing the conditions in most of the cases.
2. New substance(s) is/are formed.
3. The chemical properties of the original substance remain the same.
4. There is an exchange of energy during this change which means that heat and light may be given out or absorbed.
5. As a result of the change, there may or may not be any change in the energy possessed by the original substance.
6. There is no change in the chemical composition of the original substance.
7. The change is permanent and cannot be reversed by changing the conditions or through ordinary physical processes.
8. There may or may not be any change in the state, size, shape, colour, and smell of the substance that undergoes this change.
9. The composition and the properties of the parent substance or substances change.
10. There is usually a change in the mass of the parent substance/s as well.

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1. Rust is hydrated ferric oxide. 2. Zinc is used for galvanising iron. 3. We get pure substances by the process of crystallisation. 4. A chemical change is usually irreversible and permanent. 5. All chemical changes involve absorption or liberation of energy.

1. Rust is hydrated ferric oxide.
2. Zinc is used for galvanising iron.
3. We get pure substances by the process of crystallisation.
4. A chemical change is usually irreversible and permanent.
5. All chemical changes involve absorption or liberation of energy.