CHEM 103 FINAL EXAM STUDY GUIDE Q&A

CHEM 103 FINAL EXAM STUDY GUIDE Q&A Question 1 1. Convert 0.00346 to exponential form and explain your answer. 2. Convert 2.76 x 104 to ordinary form and explain your answer. Your Answer: 1. 0.00346 = smaller than 1 = negative exponent, move decimal 3 places = 3.46 x 10-3 2. 2.76 x 104 = positive exponent = larger than 1, move decimal 4 places = 27600 Question 2 Do the conversions shown below, showing all work: 1. 28oC = ? oK 2. 158oF = ? oC 3. 343oK = ? oF 1. 28oC + 273 = 301 oK oC → oK (make larger) +273 2. 158oF - 32 ÷ 1.8 = 70 oC oF → oC (make smaller) -32 ÷1.8 3. 343oK - 273 = 70 oC x 1.8 + 32 = 158 oF oK → oC → oF Question 3 Show the calculation of the number of moles in the given amount of the following substances. Report your answerto 3 significant figures. 1. 12.0 grams of Ca3(PO4)2 2. 15.0 grams of C9H8NO4Cl 1. Moles = grams / molecular weight = 12.0 / 310.18 = 0.0387 mole 2. Moles = grams / molecular weight = 15.0 / 229.61 = 0.0653 mole