In this paper we prove some weighted W-2,W-2-a priori bounds for a class of linear, elliptic, second-order, differential operators of Cordes type in certain weighted Sobolev spaces on unbounded open sets Omega of R-n, n >= 2. More precisely, we assume that the leading coefficients of our differential operator satisfy the so-called Cordes type condition, which corresponds to uniform ellipticity if n = 2 and implies it if n >= 3, while the lower order terms are in specific Morrey type spaces. Here, our analytic technique mainly makes use of the existence of a topological isomorphism from our weighted Sobolev space, denoted by W-s(2,2) (Omega) (s is an element of R), whose weight is a suitable function of class C-2((Omega) over bar), to the classical Sobolev space W-2,W-2(Omega), which allow us to exploit some well-known unweighted a priori estimates. Using the above mentioned W-s(2,2)-a priori bounds, we also deduce some existence and uniqueness results for the related Dirichlet problems in the weighted framework.