Grade 9 Unit Test – Atoms and Elements

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					SNC2D – TEST A                                                                 Name:
                                     Grade 9 Unit Test – Atoms and Elements
A. Multiple Choice: Circle the most correct answer. (5 Marks)
1. When performing electrolysis on water, Proust observed:
a) That the mass of the water before the reaction was equal to the mass of the hydrogen produced after the
b) When he used a higher voltage, more oxygen was produced;
c) That equal amounts of oxygen and hydrogen were produced in every case;
d) None of the above.
2.     What sub-atomic particle is not present in the nucleus of atoms:
a)     Protons;
b)     Neutron;
c)     Electrons;
d)     All are present in the nucleus of atoms.
3.     I have a mixture that has settled into two distinct phases. The mixture can be classified as
a)     A solution;
b)     A colloid;
c)     A homogeneous mixture;
d)     An emulsion.
4.     A glowing flint placed into an unknown gas re-lit. The gas must be
a)     Hydrogen;
b)     Carbon Dioxide;
c)     Water Vapour;
d)     None of the above.
5.     Octane has a chemical formula of C8H18. The mass of one mole (molar mass) of Octane is:
a)     13.02 g/mol;
b)     30.16 g/mol
c)     34.19 g/mol;
d)     97.096 g/mol;
e)     104.15 g/mol;
f)     114.23 g/mol.

B. Short Answer: Answer all the following questions in the spaces provided.
6. Using precise terms, provide DETAILED observations for the sample passed around the class (3 Marks)

7. Identify at 3 indicators which would suggest that a chemical change occurred. (6 Marks)



8. When a fire burns a log of wood, the mass of the ashes left behind is much less than the mass of the
   original log. Is this an exception to the Law of conservation of mass? Explain CAREFULLY. (2 Marks)

9. a) On the table below highlight the position of the metals, non-metals and metaloids. (1.5 Marks)
   b) Identify the position of the most reactive metal to water? (0.5 Marks)

10. a) With the aid of a LABELLED diagram to explain his experiment, describe how Rutherford came to the
       conclusion that the atom was made up mostly of empty space, with a massive, positive nucleus in the
       center? (5 Marks)

             Experimental Diagram

   b) Why didn’t the presence of electrons around the atom affect his experimental results? (1 Mark)
11. Draw proper “Bonding diagrams (i.e. with Electrons) for the elements shown below (2 Marks x 2):

         Magnesium (Mg) and Fluorine (F)                            Carbon (C) and Hydrogen (H)
                  IONIC BOND                                           COVALENT BOND
                (Metal / Non-Metal)                                   (Non-Metal / Non-Metal)

C. Applied Questions: answer the following on a separate sheet of paper. Be sure to show all your work.

7. When CaCO3.7H2O is heated the water evaporates leaving a flaky white residue. What percentage by
   mass of Calcium Carbonate Heptahydride is water (Hint: Use calculations from law of definite proportions
   lab)? (4 Marks)

What is an isotope? (0.5 Marks)

Balance the following equation. (0.5 Marks)

    LiBF4 +          H2O             H3BO3 +          HF +         LiF

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