My fully latched on 11 weeks old baby vomit yellow kind of liquid/chuck. What is this so? He has 4 to 5 wet diapers, no fever. He is latching on well too.

Babies tend to spit up when they drink too fast, too much. Maybe you can feed her smaller "meals" at more frequent periods. As for the yellow spit up, I've never seen such a thing before. I think you should monitor this for a day and if it doesn't go away, best to see the doctor and seek professional medical advice. http://www.mayoclinic.org/healthy-lifestyle/infant-and-toddler-health/in-depth/healthy-baby/art-20044329?pg=2