Can I upgrade to these RAMs?

Hi, I just bought my first mac. It was a base iMac 5k model (late 2015). As you know, it comes with 8Gb of ram. And so happened, that I have some RAMs from my old laptop. I am just not sure if it's a good idea to add them. Can someone tell me if I can add (or change to) these RAMs? I have 2x8Gb of these: http://www.kingston.com/dataSheets/KVR16S11_8.pdf
If I understand good, they are slower (1600Mhz), but will I feel the difference?

Thanks!