“Wie” vs “Was”

I saw this sentence yesterday “Wie ist der Wechselkurs”.
1. Can you use “Was” instead? If not, why?
2. Is there a specific rule for when to use “Wie” instead of “Was”?
 

Hallo RexV!

Wie  and was are two different question words, wie meaning "how" and was meaning "what." So these words are used to ask very different types of questions.

I would recommend going through Lesson 3.7 "Asking Questions" (https://members.rocketlanguages.com/members/german/lessons/67/3-7-asking-questions) to learn about the different question words and how they're used.

I hope that this is helpful!

Tschüss!

Liss