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23 Questions on Introduction to Chemistry I - Old Exam 1 |, Exams of Chemistry

Material Type: Exam; Class: Chemistry 1 - Introduction; Subject: Chemistry; University: Northern Arizona University; Term: Forever 1989;

Typology: Exams

2009/2010

Uploaded on 08/14/2010

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NAME _____________________
CHEMISTRY 151
EXAM 1
Dr. Hascall 9/24/09
23 questions on 4 pages. DO NOT OPEN UNTIL INSTRUCTED TO DO SO
There is a Periodic Table and other useful information at the end of
the exam. You may detach that page.
It is your responsibility to check that you have all of the pages.
Pay attention to the point value of questions and plan your time accordingly. If
you are not sure how to answer a question, move on to another one and come
back later if you have time.
Show all work on problems and make sure your work and final answer are clear,
and contain appropriate units and numbers of significant figures. Use the backs
of the sheets to make notes.
CHEATING IN ANY FORM WILL NOT BE TOLERATED
Good luck!
pf3
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pf5

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Download 23 Questions on Introduction to Chemistry I - Old Exam 1 | and more Exams Chemistry in PDF only on Docsity!

NAME _____________________

CHEMISTRY 151

EXAM 1

Dr. Hascall 9/24/0 9

23 questions on 4 pages. DO NOT OPEN UNTIL INSTRUCTED TO DO SO

  • There is a Periodic Table and other useful information at the end of the exam. You may detach that page.
  • It is your responsibility to check that you have all of the pages.
  • Pay attention to the point value of questions and plan your time accordingly. If you are not sure how to answer a question, move on to another one and come back later if you have time.
  • Show all work on problems and make sure your work and final answer are clear, and contain appropriate units and numbers of significant figures. Use the backs of the sheets to make notes.
  • CHEATING IN ANY FORM WILL NOT BE TOLERATED
  • Good luck!

1 – 18 Multiple choice questions (3 pts each): Bubble in the correct answer on the Scantron. Make sure your name and test color are on the Scantron.

  1. Expressed in standard notation, the number 3.75 × 103 is: (a) 0.00375 (b) 0. (c) 375000 (d) 3750
  2. If you did the following calculation, how many significant figures should your answer have? 5.3956 × 13. (a) 2 (b) 3 (c) 4 (d) 5
  3. What is the volume of a 2.5 kg block of metal that has a density of 4.75 g/mL? (a) 530 mL (b) 11.9 mL (c) 1.9 mL (d) 0.00 053 mL
  4. An atom of the isotope potassium-39 contains how many neutrons? (a) 19 (b) 20 (c) 39 (d) 58
  5. Which of these substances would you expect to exist as molecules? (a) CO 2 (b) Na (c) MgSO 4 (d) KBr
  6. Considering that the atomic mass of lithium is 6.94 amu, which of these statements best describes lithium atoms in nature? (a) All Li atoms have a mass number of 6 (b) All Li atoms have a mass number of 7 (c) Lithium exists mainly as 6 Li, but with a small amount of 7 Li (d) Lithium exists mainly as 7 Li, but with a small amount of 6 Li
  7. Which of these elements is an alkali metal? (a) Na (b) O (c) Fe (d) Zn
  8. The formula for sodium phosphate is: (a) Na 3 P (b) Na 3 PO 3 (c) Na 3 PO 4 (d) Na 2 PO 4
  1. Which of the following are examples of redox reactions? I 4 Al ( s ) + 3 O 2 ( g ) → 2 Al 2 O 3 ( s ) II Na 2 CO 3 ( s ) + 2 HCl ( aq ) → 2 NaCl ( aq ) + H 2 O ( l ) + CO 2 ( g ) III 2 NaCl ( aq ) + Pb(NO 3 ) 2 ( aq ) → PbCl 2 ( s ) + 2 NaNO 3 ( aq ) IV Cu(NO 3 ) 2 ( aq ) + Zn ( s ) → Zn(NO 3 ) 2 ( aq ) + Cu ( s ) (a) I only (b) I and IV (c) II and III (d) all of them
  2. What is the oxidation number of Cl in perchlorate ion, ClO 4 –? (a) – 1 (b) +1 (c) +3 (d) + 19 – 23: Problems: Show your work clearly!
  3. (8 pts) What is the theoretical yield (in grams) of PI 3 when 27.0 g P and 68.0 g I 2 react? 2 P ( s ) + 3 I 2 ( s ) → 2 PI 3 ( s )
  4. (10 pts) Ethylene glycol, a compound of carbon, hydrogen and oxygen, has a molar mass of 62 g/mol and is 38.7 % C, 9.7 % H and 51.6 % O by mass. Calculate the molecular formula of ethylene glycol. (Hint: Determine its empirical formula first.)
  1. (8 pts) 10.0 g of Mg(NO 3 ) 2 is dissolved in enough water to give 100.0 mL of solution. What is the molarity of this solution?
  2. (8 pts) 28.3 mL of a solution of hydrochloric acid completely reacts with 0.256 g of Na 2 CO 3. Calculate the molarity of the acid. The balanced equation for the reaction is: Na 2 CO 3 ( s ) + 2 HCl ( aq ) → 2 NaCl ( aq ) + H 2 O ( l ) + CO 2 ( g )
  3. (4 pts each) In each case: ( i ) write a balanced equation for the reaction that would occur when the given aqueous solutions are mixed. ( ii ) give the balanced net ionic equation. You must include the symbols for states such as ( s ), ( l ), ( g ) and ( aq ). If no net reaction would occur, write “no reaction.” (a) Cu(NO 3 ) 2 ( aq ) + KOH ( aq ) → (b) HBr ( aq ) + NaOH ( aq ) → (c) NaCl ( aq ) + Zn(NO 3 ) 2 ( aq ) →