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1. Give two examples of changes in which energy is evolved. 2. What type of change is involved in heating sugar?3. State five physical changes observed by you.4. Write important differences between physical and chemical changes.5. Give two examples of physical changes and two examples of chemical changes.6. Changes involve energy. Explain it.7. Burning of a candle is considered as a physical as well as chemical change. Explain.8. What happens when water is added to quick lime? What kind of change is it? Meaning less answer will be reported......Ans it properly....Chemistry based question |
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Answer» ans.1 When you burn something in presence of oxygen, energy is given out in the form of heat. The burning of a matchstick, the energy evolved is due to a chemical change. When we whitewash our house, we dissolve quicklime in water. Bubbles and gases evolve and the container becomes hot.Explanation:2.Burninga sugar cube is a chemical change. Fire activates a chemical reaction between sugarand oxygen. The oxygen in the air reacts with the sugar and the chemical bonds are broken.3.Crushing a can.Melting an ICE cube.Boiling water.Mixing sand and water.Breaking a glass.Dissolving sugar and water.Shredding paper.Chopping wood.4.The difference between a physical reaction and a chemical reaction is composition. In a chemical reaction, there is a change in the composition of the SUBSTANCES in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition. 5.physical change Crushing a can.Melting an ice cube.chemical change Burning wood.Souring milk.6.an alteration in the physical and chemical properties of matter due to the effect of some kind of energy. E.g. Here ice get energy from the surroundings and get converted into water. means here energy is involved in changing the state of ice to liquid7.When a candle burns, both physical & chemical changes occur. Physical Changes in Burning Candle: On heating, candle wax melts and form liquid wax. It is a physical change. ... This wax vapor near to flame burns and gives new substances like Carbon Dioxide, Carbon soot, water vapours, heat and light8.When Water is ADDED to quick lime, then a lot of heat is released and heavy fizzing occurs because Slaked lime is fromed ( Calcium Hydroxide). CaO + H₂O → Ca(OH)₂ + heat energy. ANSWER: When quick lime is added to water, it reacts to form calcium hydroxide (slaked lime).HOPE it will help you mark me as brilliant |
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