The federal government has enumerated powers explicitly stated in the Constitution. All other powers belong to the states or the individual.
Yes, but Congress has been delegated power under the 14th Amendment to pass legislation to ensure that no person is deprived of life, liberty or property without due process of law. Pro-lifers have always argued that unborn children are persons too unless you reject this argument then the 14th Amendment provides the federal government with the power to prohibit abortion. Not to mention the fact, that a constitutional amendment can never violate the 10th Amendment.