(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 kommentar(er)
