What is the difference between an atom and a mixture?

A mixture is a combination of two or more pure substances. An atom basically just one small unit of an element.

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

: )

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.