Slow ram and Chip ram are not the same things. Depending on the context slow ram can be used to mean as chip ram, but it's better to call chip ram, chip ram. Anyway, the answer to your question is, simply it won't be recognised, and you won't be able to use it. There may be eggzentric trap door expansions which use gary adapters to map to ranger mem space, but I doubt they will work on your A500+.
The maximum mem you can get on your A500+ is 2 mb chip ram via trap door slot and 8mb on the side car. That is without an accelerator which plugs onto 68k socket. Acclerator cards are out of these boundaries and can hold upto 128 mb of Fast ram.
Now of course when an accelerator comes into picture, you see the FastRam/SlowMem terminology turning meaningless, cause the mem on the sidecar which we called fast ram will be slow when compared to fast ram on the accelerator board. So I prefer to call them slow mem, and chip ram as chip ram. The difference between them is of course the chipset can't access the slow mem, but it can access chip ram.
To get a better picture of things, check the
Amiga System Memory map. This map covers the whole 68000 addressing range (16 bit). The 68030+ accelerators have 32 bit addressing range, so they are not limited to this map.
