Sadly Apple's laptops don't have removable chips (thin laptops tend not to). Here's a view of the logic board from the backside: MacBook Logic Bd. The larger chip with the grey thermal paste is the CPU, the other is the GeForce 320M GPU.
As you already have the premium model (2.4 GHz) there is no logic board swap out possibility within the models series. Likewise there is no newer logic board possible either as Apple completely redesigned the MacBook in 2015. So upgrading the CPU is not possible,
But! You do have some areas which you can gain performance!
To start with, I would bump the RAM up to 10 GB or 12 GB.
The next area would be the storage. Here you could swap out the HD with something bigger, I would go with a SSHD from Seagate as the best option here as your systems SATA port is only SATA II (3.0 Gb/s) so you'll need to make sure the drive you do get can run at this I/O speed (many don't). The other option here is to take the big leap to a SSD. Just make sure you get one that has enough space. After you load it up you want to have 1/3 to 1/4 of the drive free more for the smaller SSD's. Again, you do need to be careful here to with the drives I/O speed some SSD's won't play well in a SATA II system.