No way to know since you don't say specifically what model you have. But you can see the requirements for yourself here:
By the way, this forum is intended for questions about old, pre-G3 hardware, and doesn't get much traffic. Hence it's not usually the forum where you'll be most likely to get help with questions regarding PowerPC or Intel Macs. There are forums specifically for more current systems.
Below are the specs for my computer. It should be able to run Mountain Lion but Apple has locked this computer system out of what is allowed claiming it only supports 1 GB of RAM which is not accurate since I had no trouble upgrading mine with 4 GB RAM. Why am I not allowed to upgrade to Mountain Lion? It can indeed work with my system if Apple takes the software locks off.
Model Name: Mac mini
Model Identifier: Macmini2,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 4 GB
Bus Speed: 667 MHz