exam 1 review key

exam 1 review key - Chem 115a Exam 1 Thursday Professor...

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Chem 115a E x a m 1 Print Name Last, First Thursday September 10, 2009 Last 3 digits SID # Professor Anna Krylov TA Name/Lab Time: Questions Points Score Grader 1 12 2 12 3 8 4 15 5 8 6 14 7 17 8 14 Total 100 Please Sign Below: ination. Signature I certify that I have observed all the rules of Academic Integrity while taking this exam INSTRUCTIONS 1. You must show your work to receive credit. 2. If necessary, please continue your solutions on the back of the preceding page (facing you). 3. YOU MUST Use black or blue ink. (No pencil, no whiteout.) 4. There are 8 problems on 8 pages. Please count them before you begin.
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1. (12 pts) (a) (2pts) The agreement of a particular value with the true value is called (circle the correct answer): a. accuracy b. error c. precision d. significance e. certainty (b) (4 pts) Fill the missing words in the sentences below: In the Scanning Tunneling Microscopy, the atoms and molecules are visualized by using ____________________ between the tip and the surface. This technique overcomes the limitations of ______________________ and allows one to see individual molecules. (d) (2 pts) Perform the following operation with correct significant figures: (4.0x10 4 )x(5.021x10 -3 )x(7.34993x10 2 ) (c) (4 pts) Manganese makes up 1.30x10 -4 percent by mass of the weight of the human body. How many grams of manganese does a person weighing 120 lb have (1.0 kg = 2.2 lb)? m=120/2.2 = 54.55 kg m(Mg)=1.30x10 -4 x54.55/100=70.91x10 -6 =7.09x10 -5 kg = 7.09x10 -2 g 2
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2. (12 points) Fill in the missing entries in each column of the table. Symbol # protons # neutrons # electrons Net Charge 39 + 19 K 2 16 S 16 31 38 +3 3. (8 pts) Balance the following equations: (a) __C 4 H 10 + __O 2 __CO 2 + __H 2 O (b) __NaNH 2 + __NaNO
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exam 1 review key - Chem 115a Exam 1 Thursday Professor...

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