3A. A silicon chip used in an integrated circuit of a microcomputer has a mass of 7.02 mg. How many silicon (Si) particles (atoms) are present in this chip?

Note: 1g = 1000 mg

3B. Suppose you are reacting 26.8 g of zinc with 68.2 g of oxygen to produce 9.6 g of zinc(II)oxide. Write the balanced chemical equation, find the limiting reagent, and calculate theoretical yield as well as % yield for the product.