Hariri High School II

Term II Chemistry Test

Name:______Date: March 7th, 2011

Class: G9 (A, B & C)Time: 60 min.

Max score: 20 pts

The nuclear charge of an atom Y1 is 9.6x10-19C, and its mass is 20.04x10-21mg.

An atom of X has 7 valence electrons. It contains a total number of electrons less than 18.

  1. Determine Z and A of the element Y1. (2pts)
  1. Specify the row and column of the element Y1 in the periodic table. Explain. (1pt)
  1. Y1 has two more isotopes. The secondisotope Y2has one more neutron than Y1. The third isotope Y3has two more neutrons than Y1.

1. Write the nuclear representation (nuclide) of the three isotopes. Justify your answer. (0.75pts)

2.The adjacent pie graph represents the three isotopes of Y.

a. Calculate the % abundance of each isotope. (1pt)

b. Deduce the average atomic mass of Y. (0.5pts)

3. Calculate the number of moles and number of atoms found in 3g of the element Y1. (1pt)

D. Write all possible electronic configuration of X. (0.5pts)

Given: 1p+ = 1.6x10-19C

1u = 1.67x10-24g

An aluminum strip is dipped in a beaker containing nickel (II) nitrate solution. After a certain time, the green color of the solution that appears due to the presence of Ni2+ ions fades, and the solution becomes colorless. Aluminum nitrate is a colorless solution. In fact, an oxidation-reduction reaction takes place, given by the following equation:

2Al +3Ni2+2Al3+ +3NiEq(I)

  1. Specify the oxidant and the reductant in the above redox reaction. (1pt)
  1. The reduction half-reaction is: Ni2++ 2e-Ni

Write the oxidation half-reaction. (0.5pts)

  1. A galvanic cell (G)overall reaction is represented by equation (I) is constructed whose.

The schema of the cathode half-cell is shown on the previous page.

1. List the materials needed to construct the galvanic cell (G).(1pt)

2. Construct and label the galvanic cell (G). (1.5pts)

  1. List the observations detected in the galvanic cell (G). (1pt)
  1. Write the cell representation of galvanic cell (G). (0.5pts)

F. A nickel strip is dipped in a beaker containing aluminum (III) nitrate solution. Justify whether a chemical reaction will or will not take place. (0.5pts)

  1. Given the adjacent diagram that represents the structural formula of urea.
  1. Draw a bar graph that represents the elements C and N (on the X-axis) with their corresponding number of valence electrons (on the Y-axis). (1pt)
  1. What is the valence and valence electrons of oxygen in urea. (1pt)
  1. Write the molecular formula of urea. (0.5pts)
  1. Give another possible Lewis structure formula of urea. (0.75pts)
  1. Modafinil is an oral drug that for improving wakefulness in patients with excessive sleepiness. The effect of modafinil is similar to caffeine. Both drugs promote wakefulness by stimulating the brain.Modafinil has the following structural formula:

  1. On your question sheet, satisfy all of the elements, making the above compounds by adding the missing atoms and lone pairs of electrons, knowing that the molecular formula of Modafinil is C15H15NO2S. (1pt)
  1. What is one use of modafinil? (1pt)
  1. Consider the following hydrocarbon CnH16.
  1. Find the value of n, knowing that the above compound is an alkane. (1pt)
  1. Name the alkane and give its order in the family. (1pt)