Physical and Chemical Changes Test - 5

According to this question the correct optionwill be ‘A’ because  Evaporation is areversible physical reaction. The reverse process is water condensing from theatmosphere onto a surface. Evaporation involves the change in state from liquidto gas. It's not the same as vaporization, or boiling, because it occurs attemperatures below the boiling point of the substance.

According to this question the correct option will be ‘B’ because A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding. Often, physical changes can be undone, if energy is input.

According to this question the correct option will be ‘A’ as Yes, It is a physical change because it's only losing air. When you put air in the balloon it's still a balloon, and when it loses air it's still a balloon. So it's a physical change since it didn't change in substance.

According to this question the correct option will be ‘A’ Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula.

According to this question the correct option will be ‘A’ because Melting of wax is physical change. In melting of wax, only the state of wax changes from solid to liquid. It is a reversible reaction and no new substance is formed. Burning of candle is both physical and chemical change. When the candle burns, the wax slowly melts which freezes after some time (Physical change).

According to this question the correct option will be ‘C’ because melting of ice and wax both are processes in which solid changes in to liquid state.

According to this question the correct option will be ‘A’ because  Photosynthesis is a chemical change process. It can be summarized in a single chemical equation, but that equation is actually the sum total of a collection of chemical reactions.

According to this question the correct option will be ‘A’ because after ripening a new product with different properties is formed hence it is chemical change.

According to this question the correct option will be ‘C’ because melting of ice is a physical change which convert in to the water.

According to this question the correct option will be ‘B’ because Combustion of magnesium ribbon involves many chemical changes.

Lactic acid bacteria (LAB) like lactobacillus are added to milk. It converts lactose sugar of milk into lactic acid. Lactic acid causes coagulation and partial digestion of milk protein casein. Milk is changed into curd, yoghurt and cheese.

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colors because the blue light has been scattered out and away from the line of sight.

Hence, scattering is the characteristic property of light which is responsible for the blue colour of the sky.

According to this question the correct option will be ‘C’ because Lime water turns milky when you pass carbon dioxide through it because a reaction that produces a white precipitate takes place. When you pass carbon dioxide through this solution, the two compounds carbon dioxide and calcium hydroxide  will react to form white and insoluble calcium carbonate which precipitates out of the solution.

According to this question the correct option will be ‘C’ because When we put an iron nail in a copper sulphate solution, we find the blue color of the solution changes to green.

According to this question, the correct option will be ‘A’ as the tearing of books pages is a physical and irreversible change. As in the tearing of paper, no new substance is formed.