Why does IB Chem feel harder than other IBs

So I've taken ib chem, AP gov, and rn I'm taking ib history, ib English hl, Ib environmental systems, and IB business management. And while those are hard, the subject material itself isn't all that hard. It's just a lot of work.

But IB Chem actually felt hard, not just alot of work. Does anyone else feel like this?