No. 6 ounces of worsted weight yarn will not even get you a decent sized knitted baby blanket.
If you are using Simply Soft, you're going to need even more yarn than what your blanket pattern calls for-- at least that has been my experience when knitting with Simply Soft. If you are knitting a full-size afghan for an adult, expect to use about 9 or 10 skeins of yarn. For a child, I'd say 6-8 skeins. For a baby, 4 or 5 skeins of yarn might be appropriate.
Without knowing your pattern and gauge, there really isn't a good way to accurately tell you exactly how much yarn you will need for a blanket. About all any of us can do is tell you that one skein of yarn won't get you much in the way of a blanket, unless you are knitting it for a small doll or teddy bear! With that skein, you do have enough to make a hat.