Exam 1 with answers_Bb

Exam 1 with answers_Bb - CHEM101-003/Exam 1/Sept. 15, 2011...

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CHEM101-003/Exam 1/Sept. 15, 2011 Name: PID: Honor Code Statement: On my honor, I have neither given nor received unauthorized aid on this assignment. Signature: Instructions: You are given these exam questions, an answer sheet, a periodic table and some blank paper. You should place your answers to be graded on the answer sheet. For fill in the blank questions involving calculations, clearly and neatly show your work next to the question on these pages (exam questions). Stop all writing promptly when time is called. 1. The law of constant composition says __________. A) that the composition of a compound is always the same B) that all substances have the same composition C) that the composition of an element is always the same D) that the composition of a homogeneous mixture is always the same E) that the composition of a heterogeneous mixture is always the same Answer: A Page Ref: Sec. 1.2 2. In the following list, only __________ is not an example of a chemical reaction. A) dissolution of a penny in nitric acid B) the condensation of water vapor C) a burning candle D) the formation of polyethylene from ethylene E) the rusting of iron Answer: B Page Ref: Sec. 1.3 3. Which one of the following is the highest temperature? A) 38 °C B) 96 °F C) 302 K D) none of the above E) the freezing point of water Answer: A E=0C which is obviously smaller than A, so E&D are ruled out immediately. C and K degrees are the same but C=K+273.15. A=38C=38+273=311, so A>C and C is ruled out. To convert F to C: C=(5/9)(F- 32), so B=96F=(5/9)(96-32)=35.6C. (Also, you might recall that normal human body temperature is 98.6F or 37C. Since A is above 37C and B is below 98.6F, “A” must be greater.) B<A, so the highest temp is A. Page Ref: Sec. 1.4 4. Gold has a density of 0.01932 kg/cm 3 . What volume (in cm 3 ) would be occupied by a 33.3 g sample of gold? (Fill in the blank. Put answer on answer sheet.) 33.3g*(1 kg/1000g)*(1 cm 3 /0.01932 kg)=1.724 cm 3 in correct sig figs=1.72 cm 3 Answer: 1.72 cm 3 Page Ref: Sec. 1.4 5. Precision refers to __________. A) how close a measured number is to other measured numbers 1
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2 B) how close a measured number is to the true value C) how close a measured number is to the calculated value D) how close a measured number is to zero E) how close a measured number is to infinity Answer: A Page Ref: Sec. 1.4 6. Accuracy refers to __________. A) how close a measured number is to zero B) how close a measured number is to the calculated value C) how close a measured number is to other measured numbers D) how close a measured number is to the true value E) how close a measured number is to infinity Answer: D Page Ref: Sec. 1.4 7. Which of the following has the same number of significant figures as the number 1.00310? A) 1 × 10
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Exam 1 with answers_Bb - CHEM101-003/Exam 1/Sept. 15, 2011...

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