What is the key differnce between a federal government and a confederate government?

The basic difference is that a confederation is basically an agreement among States. Whereas a federation is a union of the states under one central government. A confederation is pretty much a single house congress lead by a congressional president. There is no Executive or Legislative Branch. A federation involves setting up a complete single government with a complete Legislature, Judiciary and Executive separate from the individual States' governments.

The common sense pamphlet i think