Chemistry !
i am not sure how to do this, so if you could explain how you got the answer that’d be great.

write the chemical equation and balance the equation.

the word equation is:
hydrogen peroxide -> oxygen gas + water

The word equation is:  

 This reaction happens when there is the decomposition of hydrogen peroxide into oxygen and water. Thus, the equation would be  

Balancing the equation requires to have the same number of atoms of each element on both the side. To balance this equation we need to add 2 water () molecules  and 2  hydrogen peroxide () molecules  . As we know, oxygen is naturally diatomic. Thus, the balancing equation would be:

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.