Mexico City airport

I am flying out of Zihua Thursday and my flight schedule has been changed and now spending near 12 hours in Mexico City, arriving there around 11:30 in the morning. Any suggestions on things to do? I will check my baggage and hopefully it is going through from Zihua all the way with no issues as it is a long trip, Mexico City-Toronto-Winnipeg...I will have one carry on that I am hoping to be able to leave somewhere at the airport so I don't have to lug it around all day. I was also told there is a large mall attached to the airport I should check. Thanks for all info...