Consider the following balanced chemical reaction: 10Fe2SO4 + 8H2504 + 2KMnO4
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5 Fe2(SO4)3 + 2MnSO4 + K2SO4 + 8H20
The reaction of 13.7 mol Fe S04, 12.9 mol H2SO4 and 3.60 mol KMnO4 will produce
mol of Fe2(SO4)3. The limiting reagent is Fe2SO4.​

well in order to answer this question you have to provide more information < 3

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.