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How does photosynthesis follow the law of conservation of mass and the law of...

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rivkah | Student, Grade 10 | eNotes Newbie

Posted April 20, 2010 at 5:08 AM via web

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How does photosynthesis follow the law of conservation of mass and the law of conservation of energy?

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krishna-agrawala | College Teacher | (Level 3) Valedictorian

Posted April 20, 2010 at 11:25 AM (Answer #1)

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Photosynthesis separate carbon-dioxide in the atmosphere in to oxygen and carbon, using the sunlight. Thus Photo synthesis  absorbs of heat or light energy that is contained in sunlight. In this way the inputs to the photosynthesis process are carbon-dioxide and light energy, and the outputs are Oxygen and carbon. Oxygen is released in the atmosphere while the carbon is used up in making food for the plants.

The amount of oxygen and carbon atoms released by photosynthesis are exactly equal to the atoms of these material contained in carbon-dioxide converted. In this way photosynthesis has conserved the mass or material, and in this way followed the law of conservation of mass.

Photo synthesis also follows the law of conservation of energy. The energy of sunlight used in the process of photosynthesis is absorbed by the molecules of carbon-dioxide before they can separate in carbon and oxygen molecules. This absorbed energy is present in the carbon and oxygen molecules and can be releases again as energy of combustion produced when carbon and oxygen combine to produce carbon dioxide.

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hart379 | High School Teacher | (Level 2) Adjunct Educator

Posted April 21, 2010 at 3:09 AM (Answer #2)

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The law of conservation of mass states that in a chemical reaction, mass is neither created nor destroyed. That means, the total mass for the reactants needs to equal the total mass of the products. The reactants for photosynthesis are 6 carbon dioxide, 6 water and sunlight. The mass of these reactants adds to equal the mass of the products, which are 1 glucose and 6 oxygen. There are equal amounts of each atom on both sides of the chemical equation. The law of conservation of energy states that energy cannot be created nor destroyed. This is a little more confusing because energy (sunlight) is a reactant in the equation and not a product, so it had to go somewhere. Energy can be converted from one form to another. In the case of photosynthesis, energy is converted from sunlight into glucose. Glucose is a carbohydrate which is a molecule that the body can break down for energy.
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graciegeller | Student, Grade 9 | eNotes Newbie

Posted June 5, 2012 at 11:06 AM (Answer #3)

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The Law of the Conservation of Mass states that during a chemical reaction, matter is neither created nor destroyed. That means the amount of matter present before the reaction is equal to the amount of matter present after the reaction. Photosynthesis occurs only in cells with chloroplasts. Plants need light, carbon dioxide, and water to perform it. First, chlorophyll and other pigments trap light energy from the sun. This energy is then used to combine carbon dioxide and hydrogen to make a sugar called glucose. Even though plants gain mass, they only gain mass because they use the glucose they produce to help them grow. When a plant grows, it gains mass. The amount of matter before photosynthesis doesn't change. The plant's atoms are simply reconfigured. The plant uses what it produces through photosynthesis, a chemical reaction, to help it gain mass. Therefore, it doesn't gain mass through the chemical reaction. It gains mass by using what it produced through the chemical reaction, which means that the amount of matter before the reaction equals the amount of matter after the reaction. It is in this way that photosynthesis is an example of the Law of the Conservation of Mass.

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