Why is photosynthesis an endothermic reaction

Now in this process, a lot of energy's being released, and that's why this is an exothermic process. Now how I like to remember this is, basically when you throw away vegetable matter, it decomposes and it becomes manure or fertilizer. And fertilizers, basically, give energy to plants, right. So in this process, energy's being released, and that's how I remember that decomposition of vegetable matter is an exothermic process.

Now I have these reactions, and let's try to identify them as exo and endothermic reactions. Now first of all, I would want you to pause the video and try this by yourself. So here in the first reaction, I can see that heat, or delta, is being mentioned on top of the arrow.

Now this symbolizes that this reaction requires heat to begin or proceed, and we know that reactions that require heat, they are called endothermic.

So this is going to be an example of endothermic reaction. Now let's look at this one. See in this reaction I can see that plus heat, or plus delta, is written in the product side. Well, this means that heat is being evolved along with the product. And in reactions in which heat is evolved or generated, is given out, we called them as exothermic reactions. So this is going to be an exothermic reaction. Here I can see that calcium oxide, plus water, is giving me calcium hydroxide.

So I can see that two reactants are combining to give me one single product. That means that this is an example of combination reactions, and we have seen earlier that, in general, combination reactions give out more heat, meaning I can guess that over here also, more heat will be given out, and such reactions are called exothermic reaction. And yes, my guess would be right over here. See, we have seen this in an experiment when you add water to a white powder of calcium oxide.

Then if you touch the container in which this reaction is happening, it will become more warm. That means a lot of energy, lot of heat, is being given out, and that's why this is exothermic. Here I see that lead nitrate is breaking down into lead oxide, nitrogen dioxide, and oxygen. So over here I can see that one single reactant, one big molecule, is breaking down, or decomposing, into multiple products.

And these reactions are called decomposition reactions. And we have seen earlier that, in general, decomposition reactions require a lot of heat. So my guess over here will be, that still this is a decomposition reaction, this will also require a lot of heat and such reactions are called endothermic reactions. A free teacher account also allows you to create playlists of games and assignments for students and track class progress.

Sign up for free today! Tags: photosynthesis , glucose , cellulose , starch , respiration , sunlight , endothermic , chemical reaction , chlorophyll , carbon dioxide , product , reactant , water , energy , reaction. Chemical Reactions in Photosynthesis Science Games.

Sign me up now! Concepts Covered The reactants in the process of photosynthesis are carbon dioxide, water, and sunlight. For Teachers. Plant leaves are the main photosynthetic organ , but other parts of the plant exposed to the light can develop chlorophyll and photosynthesise. The carbon dioxide required for photosynthesis comes from the air.

It enters leaves through the stomata. Water enters the plant through the roots, and is transported to the leaves in the xylem. Oxygen is formed as the waste product. Some is used for respiration by the plant. The excess is released from the leaves, making it available for respiration to animals and many microorganisms.

During the light, provided the rate of photosynthesis is sufficiently high, plants, give out oxygen. The overall reaction for photosynthesis as given above is a simplification.