Hi I have lost my remote key and I was just wondering if I use my spare key will it work. Or will the alarm go off I just wanted to know before I tried it and the alarm going off and having no way of turning it off. Also will I be able to use the spare key to drive around with no problem.

The spare key will run the car with no problems, you just need to put the key in the ignition and turn to position I to stop the alarm.
I would strongly recommend you source a second key though as the cost of replacing your remaining key in the case of loss or damage will be high.
Buy a brand new complete key off eBay and contact a local Auto Locksmith to cut and programme it rather than approaching a Ford dealer as else you will get a hefty bill from them.