I am trying to find how many grams are in 5 moles of oxygen, should I use the molar mass of oxygen or 6.02 x 1023 particles/ 1 mole as my conversion factor?

its not a choice. you dont choose if you want to be gay or straight.

answer; /// i do believe that the correct answer is (c)nuclear bond

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.

just did the assignment and the answer was #1 +2 n