The location of the object is it a condition that the object exists in. A meeting, on the other hand, is defined by its location. If there is no location, there is no meeting. Nationality, composition, profession, gender, race, color, and personality traits all define who or what something or someone is. They are characteristics.
Time is self defining.
Mood and anything else that is not a defining characteristic is a condition. Some students have some confusion when it comes to the verb ir as it relates to -ir verbs. They try to use a conjugated form of ir in conjunction with a conjugated -ir verb, regardless of the circumstance. It is helpful to explain the difference early on, before the student becomes confused with -ir verbs. Perhaps the easiest approach is to classify ir as an -ir verb that is irregular because it has no stem.