Run-on Sentences

Is the sentence "I work hard during my English class I have no homework." written correctly or is it a run-on sentence?

Is the sentence "The eagle soared high above the trees and mountains, and it was beautiful." written correctly or is it a run-on sentence?

I am so tired I can't wait for the holiday break!

Is this a run on? Two cowboys came to town they were looking for gold.

Is this a run on? They heard about some gold in this town.

Is this a run on? You need a license to look for gold they didn't have one.

Is this a run on? They traded their horses for the license.

Is this a run on? They couldn't get to the gold mine without the horses.

Is this a run on? That was easy to fix they walked up the trail.

Is this a run on? One backpack was too heavy to carry up the mountains.