Can I use whatsapp with a number belonging to another phone
Answer is 'Yes', you can use it on your S5 seamlessly while using SIM in another device.

• Your Whatsapp contacts doesn't see any change.

• Remember Whatsapp can only be use on single device at a time(not whatsapp web) that means if you try to open it in your Moto device than you Galaxy device 's account will be closed.