Learn Spanish (Latin America): El jarrón está encima de la mesa.

Yes, you could! En means 'on' or 'in' and is very common. However, encima de is more specific and means exactly 'on top of'. It is highly useful when you want to be precise about the location.

Why is the word de needed after encima?

In Spanish, compound prepositions of place like encima, debajo (underneath), and detrás (behind) require de to connect them to the object you are referencing. Think of encima de as a set phrase meaning 'on top of'.

Can I drop de la mesa if the table is already obvious?

Yes! If someone asks where the vase is and the table is obvious from context, you can simply say El jarrón está encima (The vase is on top). You only need de when you are actually naming the object it is resting on.

Why do we use está instead of es for the vase?

We use está (from the verb estar) because the sentence is talking about physical location. Even though a table might seem like a somewhat permanent spot for a vase, Spanish always uses estar for the physical location of people, places, and things.