(d) Using the symbols in the legend above, draw particles in the following beaker to represent the relative amounts of the two species, CH3NH2 and CH3NH^+3 , in the solution after the first 5.00mL of titrant had been added to the CH3NH2(aq) solution.

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

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.