Those chips are 1024x4, meaning 1024 locations, each holding 4 bits. They could be arranged two by two for an 8 bit computer.
In the past, there existed 12-bit computers, 36-bit computers and other weirdos, so memory chips were commonly made narrower so that you could build them together for your particular data width. Even 1-bit RAM wasn't unusual. This is what the "x4" means. It's 4 bits per memory location.
The very similar chip,
MM2114N is used in the Commodore 64 for the Color RAM, a region occupying 1 kilobyte, but only the lower half of each byte actually gets stored.
From what I can see, you've got sixteen of them, which could logically be 8 kilobytes.