Q1) Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following changes with a suitable example.
Q2) State whether the following statements are true or false. If false write - the correct statement.
Q2) Differentiate between a physical change and a chemical change with reference to -
Q3) Give three reasons why the melting of wax is considered a physical change while burning a candle, a chemical change.
Q4) State the observation seen when milk in a dish is kept aside for a few hours or more. Is the change which occurs - a physical change or a chemical change. Give reasons.
Q5) State what is meant by the term - interconversion of matter. Is interconversion of matter a physical change or a chemical change.
Q6) Ice kept in a beaker, slowly melts and turns into water. The water in the beaker on solidification i.e. freezing turns back to ice. Give four reasons why the change from ice to water and water back to ice is considered a physical change.
Q7) Explain the term - ‘sublimation’. Is sublimation of naphthalene - a physical or a chemical change. Give reasons.
Q8) Ammonium Chloride is also a sublimable solid. Give a reason why sublimation of ammonium chloride involves a physical and a chemical change.
Q9) State why the addition of sodium chloride to water is considered a physical change, while the addition of dilute sulphuric acid to zinc is considered a chemical change.
Q10) Photosynthesis is a natural process by which green plants manufacture food in the presence of sunlight,
Q11) Give reasons why - separation of mixtures e.g. iron from a mixture of iron and sulphur is a physical change, but heating a mixture of iron and sulphur is considered a chemical change.
Q1) Fill in the blanks with the appropriate words for each of the statements given below:
Q3) Match the examples of changes in List I with the correct
|List I||List II|
|1. Expansion of a steel rod on heating||A. Physical|
|2. Rotting of eggs||B. Chemical|
|3. Milk turning sour|
|4. Tarnishing of copper|
|5. Separation naphthalene from a mixture of naphthalene and sodium chloride|
Q4) Fill in the blanks with the correct words for each of the statements given below:
Q5) Name the following
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