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(CHEM1020)[2012](f)midterm~ckblai^_70238.pdf
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THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
DEPARTMENT OF CHEMISTRY



Name: Student ID:
CHEM 1020 General Chemistry 1B Midterm Examination
Answer Key
Date: Thursday, November 8th, 2012
Time Allowed: 90 minutes
Total Points: 90 points



*





Part I. Multiple Choices (2 points each, 64 points total).
For each question, select the most appropriate answer by either writing the letter out in empty box OR by circling your choice.

1.1. Which of the following is a chemical property of methanol (CH3OH)?
C


A) It is a liquid at room temperature.
B) It freezes at -98 C at 1 atm pressure.
C) Combustion of methanol produces a pale-blue flame
D) It has a density of 0.791 g/cm3 at 20 oC
E) None of the above

1.2 The boiling of water is a
B


A) physical change because the water just disappears
B) physical change because the gaseous water is chemically the same as the liquid
C) chemical change because heat is needed for the process to occur
D) chemical change because a gas (steam) is given off
E) chemical and physical damage

1.3 How many significant figures are there in the number 0.04560700?
C


A) 4
B) 5
C) 7
D) 8
E) 9

1.4 What is the best answer to report for (481 0.0010) + 24.21?
C


A) 24.6910
B) 24.691
C) 24.69
D) 24.7
E) 25

1.5 Which of the following was NOT explained by Dalton's atomic theory?
C


A) the law of conservation of mass
B) the law of multiple proportions
C) the difference between isotopes of an element
D) the difference between elements and compounds




1.6 The atomic masses for elements are
B


A) actual masses determined by weighing individual atoms.
B) relative masses determined by comparison with a standard reference.
C) the same as the atomic number.
D) unknown.

1.7 Atoms having equal or nearly equal electronegativities are expected to form
C


A) no bonds
B) polar covalent bonds
C) nonpolar covalent bonds
D) ionic bonds

1.8 What did Rutherford conclude from his experiments?
C


A) Atoms are solid spheres, with no empty space.
B) Atoms have a large nucleus with a negative charge.

C) Atoms are mostly empty space, with a small positive nucleus.

D) Atoms are mostly empty space, with a small neutral nucleus.

E) Atoms have a large nucleus, with a positive charge.



1.9 Which of the following statement(s) concerning the Bohr model is/are correct?
D


A) The model can explain the emission spectrum of lithium.
B) The model suggests that the energy of the electron in a hydrogen atom cannot be continuous.
C) The model suggests that the distance between the electron and the nucleus in a hydrogen atom cannot be continuous.
D) Two of them E) All of them F) None of them

1.10 Which of the following statements is/are true?
E


A) and have the same number