Find the % yield for this SN2 reaction.?

A reaction of 3.90 grams of 1-chloropentane with excess sodium ethoxide in ethanol was carried out, as shown in the mechanism below. The actual yield was 3.57 grams of product. Find the % yield for this SN2 reaction. (You need to identify the product first!!) Give your answer in %, to three significant figures without the units.