What is the connotation when using 〜ものだから and 〜もの in a sentence? In my text, they state these examples:
The first set is 〜ものだから:
上着を脱いでもいいですか。 暑いものですから。
Can I take my jacket off? I'm feeling a bit hot.
遅くなってごめん。 道路が混んでいたもんだから。
I'm sorry I'm late. I got caught in a traffic jam.
The second set is 〜もの:
パーティーには行かなかったよ。 知らなかったんだもの。
I didn't go to the party, because I didn't know it was on.
しょうがないよ。 子供なんだもん。
It can't be helped. He's just a kid.
I was told that one is used more often to assert a reason or excuse for something being done, and the other for expressing feeling. Is this true? Other than that, is there any defining line between the two examples?
EDIT: I removed the question about whether a form was meant for subjectivity or objectivity.