Sunday, August 5, 2012

1st Quarter Chemistry 2012: Reviewer


Time Frame: 5 mins
Source: http://www.avon-chemistry.com/nuclear_practice.htm


Hi everyone! 
This is a quick test for chapters 4 and 5 of our textbook. Have fun!
MULTIPLE CHOICE:

  1. 1.      Cathode rays are:


        
  A  
negatively charged particles

        
  B  
positively charged particles

        
  C  
nuclei of a helium atom

        
  D  
fast moving neutrons

  1. 2.     The neutral atoms of all of the isotopes of the same element have:


        
  A  
the same mass numbers

        
  B  
equal numbers of neutrons

        
  C  
the same number of electrons

        
  D  
different number of protons

  1. 3.      Which statement is true about an isotope?


        
  A  
There can be more than one type of isotope for an element.

        
  B  
All isotopes for an element has the same number of protons and the same mass number.

        
  C  
Isotopes can have different numbers of protons.

        
  D  
All isotopes are not radioactive.

  1. 4.      How many electrons are in an oxygen atom?

        
  A  
2

        
  B  
6

        
  C  
8

        
  D  
10


  1. 5.  Copper has an atomic mass of 63.5 amu. Why is the atomic mass NOT a whole number?

        
  A  
All copper atoms have identical chemical properties.

        
  B  
The fractional number results from the fact that protons and neutrons have different masses.

        
  C  
Every copper atom has an atomic mass of 63.5 amu.

        
  D  
There are at least two naturally occurring isotopes of copper.

  1. 6.      Which symbol represents an atom that contains the largest number of neutrons?

 

        
  A  
U-235

        
  B  
Pa-231

        
  C  
Np-239

        
  D  
Pu-240

        
  E  
U-239

  1. The number of protons in fluorine-23 is 

        
  A  
6

        
  B  
8

        
  C  
9

        
  D  
14

        
  E  
23

  1. Find the average mass of an element if the relative amounts are as follows:
    Isotopic Mass: Percentage:
    75 amu ----------- 2.3%
    77 amu ----------- 15.7 %
    78 amu ----------- 4.5 %
    80 amu ----------- 7.1 %
    81 amu ----------- 70.4 %
     

        
  A  
77.25 amu

        
  B  
78.01 amu

        
  C  
79.09 amu

        
  D  
80.03 amu

        
  E  
81.09 amu

  1. Which of the following is NOT true about chemical reactions? 

        
  A  
After a chemical reaction, the protons and neutrons within the atom have not changed.

        
  B  
After a chemical reaction, there are new bonds formed while others bonds were broken.

        
  C  
After a chemical reaction, an electron may enter the nucleus and change a proton to a neutron.

        
  D  
After a chemical reaction, the boiling points and melting points of the new products are different.

  1. How many protons, neutrons, and electrons are in one atom of Pb-212 (atomic number 82)?


        
  A  
212 p+, 82 n0, 212 e-

        
  B  
82 p+, 212 n0, 212 e-

        
  C  
82 p+, 212 n0, 82 e-

        
  D  
82 p+, 82 n0, 212 e-

        
  E  
none of the above are correct


Did you have fun? Here are the answers!

1. a
2. c
3. a
4. c
5. d
6. e
7. d
8. d
9. c
10. e

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