Q.2.(a) Cutting a log of wood into pieces is a chemical change. (b) Formation of manure from leaves is a physical change. (c)Iron pipes coated with zinc do not get rusted easily. (d)Iron and rust are the same substances. (e)Condensation of steam is not a chemical change. Q.3.Fill in the blanks in the following statements: (True/ False)Ĭorrect statement: Cutting a log of wood into pieces is an irreversible physical change.Ĭorrect statement: Formation of manure from leaves is a chemical change.Ĭorrect statement: Iron and rust are two different chemical substances. (c) Two methods by which rusting of iron can be prevented are _ and _ (a) When carbon dioxide is passed through lime water, it turns milky due to the formation of. (d) Changes in which only _ properties of a substance change are called physical changes. (e) Changes in which new substances are formed are called _ changes. (Citric acid) (Sodium hydrogen carbonate) (Carbon dioxide) Lemon juice + Baking soda -> C02 (bubbles) + Other substances The reaction between baking soda and lemon juice can be given as below: When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. When a candle burns, both physical and chemical changes take place. When a candle burns, both physical and chemical changes occur: Give another example of a familiar process in which both the chemical and physical changes take place.Īns. (i) Physical change: melting of wax, vapourisation of melted wax. ![]() (ii) Chemical change: Burning of vapours of wax to give carbon dioxide, heat and light. ![]() LPG is another example in which physical change occurs when LPG comes out of cylinder and is converted from liquid to gaseous state and a chemical change occurs when gas burns in air. We can say that setting of curd is a chemical change because we can not get the original substance, i.e., milk back and a new substance is formed with different taste, smell and other chemical properties How would you show that setting of a curd is a chemical change?Īns. ![]() Burning of wood is a chemical change because in burning new substances are formed as Explain why burning of wood and cutting it into small pieces are considered as two different types of changes. Wood + Oxygen -–> Charcoal + Carbon dioxide + Heat + Lightīut cutting it into small pieces is physical change because no new substance is formed.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |