Will a precipitate form if copper chloride and sodium sulfate are mixed?

Consider the possible reactions that can occur when you do this. The copper chloride solution is a solution of copper ions and chloride ions, and the sodium sulfate solution is a solution of sodium ions and sulfate ions. If you mix the two solutions all that can happen is that the ions 'change partners' to give copper sulfate and sodium chloride, both of which are quite soluble in water. The simple answer to your question is therefore 'no'.