1. There are two seats in the corner.
2. There are two chairs in the corner.
(Does #1 mean #2?)
3. Listen carefully in hearing.
4. Listen carefully when you hear.
(Are both the same?)
A seat might not be a chair but places on a couch or bench or two car seats for children left in the corner to be picked up by grandmother when she comes to take them to the concert I suppose.
Listen carefully in hearing could be listen carefully in the budget hearing before the city council.
Listen carefully when you hear seems to be directed more generally.
Both are terrible sentences.
Depending on the intended meaning the first could be more explicitly: "Listen carefully in the public hearing." or "Listen carefully when Joe talks".
The second one could be: " When you listen to something, pay attention."