Can i make a flight with 30 minute layover?

I'm flying from iowa to chicago and then to philadelphia in october, it says we're scheduled to land at chicago at 1245pm and leave to philly by 135pm… We land at T3 and leave from T3 also, american airlines, so i won't have to transfer terminals but i have only been thru chicago a few times, i know every flight is different, usually they land late even when the weather is perfect, but does this seem like enough time? I will run as fast as i can but what does everyone think? Is this reasonable amount of time to make it to my gate in time? Maybe i can have them call the pilot and tell them to wait?

You can make such a flight as you described, but it is not a guarantee. If you plane lands late, you will likely miss the connection. If there's a long wait on the ground before you get to the terminal, you will likely miss the connection. If your incoming flight is changed to another terminal (that does happen), you will likely miss the connection. I would not feel comfortable with the situation that you described. Having the same airline is a plus, so is being at the same terminal, but the Chicago terminals are quite large, and things like delays do happen.

That's risky. Even if your first flight is on time it takes a while to deplane especially if you're sitting somewhere in the back. It's possible to make it, but also easily possible that you won't.

I doubt it. If the incoming flight is in any way late to arrive at the gate, then you will probably miss the outgoing flight. Remember that the outgoing flight will close the doors well in advance of the stated departure time.

I would never make a reservation with that short of a connection time.

If everything is on time, then you shouldn't have any trouble making that connection. But if your first flight is even just a little late, then there's a good chance you'll miss it. If the airline is offering that itinerary, then it considers it a doable connection and they will take care of rebooking you if you miss it - although that doesn't really help when you're the one stuck in the airport in that situation.

They usually will not hold a flight for an individual. The doors to the plane usually close 10-15 min before departure and they will not reopen them once that happens.

It's not ideal but provided your first flight is on time, you should make it.
The only good thing is there are multiple flights a day between Chicago and Philadelphia so if you do end up missing the flight, they'll get you on the next flight with open seats

That's a 50-minute layover, not 30 minutes. If the first flight arrives on time, no problem. If it doesn't, your chances decrease the later it arrives. They will not hold a plane for one passenger unless you're the President or you own the airline. Last time I flew, 20 of us were going to miss our connection because our flight was arriving late. They only needed to hold the departing flight for ten minutes but they didn't. Same airline on both flights.

The airlines have done a lot of research on how short their transfers can be at each airport. They don't want to leave people stuck.
If your plan arrives on time and the next departs on time, that's 50 minutes. If they are allowing you to purchase this ticket, they are saying it's enough time for an "average" person.

The 2nd flight will know about your transfer. If it's just you, who is late, they won't hold the plane. If there are many people who are delayed, they may.

That is a really tight connection but know that terminal 3 at O'Hare has a number of different concourses. I suggest you get a seat closer to the front of the plane and ask the flight attendants when you are close to landing what gate your flight from Iowa will arrive at and what gate your flight to Philadelphia will depart from. Tell the flight attendant you only have a 30 minute connection. Hopefully you get lucky and the flight arrives early so you have a longer connection time.

Can it be done? YES
Will it happen the day you try? MAYBE
No guarantee your first flight arrives on time.
What do you expect to happen if you miss the connection?
Suggest you book a longer connection.
IF the earlier plane has room in most cases you can transfer to earlier flight at no extra charge.

It can be done USUALLY. Not guaranteed.