LATIHAN SOAL UJIAN UTS KIMIA DASAR I

Selamat Mengerjakan soal-soal ini. Semoga bermanfaat.

1. The first step in obtaining elemental zinc from its sulfide ore involves heating it in air to obtain the oxide of zinc and sulfur dioxide. (a) Calculate the mass of O₂ required to react with 7.00 g of zinc sulfide. (b) Which is the limiting reactant?. (c) How much sulfur dioxide is produced?

2. Zinc and sulfur react to form zinc sulfide, a substance used in phosphors that coat the inner surfaces of TV picture tubes. In a particular experiment 12.0 g of Zn are mixed with 6.50 g S and allowed to react. (a) Which is the limiting reactant? (b) How many grams of ZnS can be formed from this particular reaction mixture? (c) How many grams of which element will remain unreacted in this experiment?

3. What is the percent composition of chloroform, CHCl₃, a substance once used as an anesthetic?

4. What is the percent composition of ethanol, C₂H₅OH, a substance once used as an antiseptic?

5. Which is Bigger if atom/ionic size? Why?

Na or K ; Na or Mg ; Al or I ‘; Na or K ; Na or Mg ; Al or I ?

6. Which has a higher 1st ionization energy? Why?

Mg or Ca ?; Al or S ?; Cs or Ba ?

7. Which is more electronegative? Why?

F or Cl ?; Na or K ?; Sn or I ?

8. Use a periodic table or use the Pauling electronegativity values to classify each of the following compounds as non-polar covalent, polar covalent, coordination covalent or ionic.

F_2; H₂ ; HF ; O₃; HBr; HCl; NH₃; NaCl; HNO₃ ; NH₄⁺ CaO; MgCl₂; dan NaF

9. Draw Lewis structures of the following.

CCl₄; CH₂O; C₂H₂; CH₃OH; CH₃CHCH₂; HCN; NH₂OH

10. Draw resonance forms for the following.

Indicate whether the resonance forms are equivalent in energy. If not, indicate the major resonance contributor (most stable). Click on the arrow to check your answers.

SCN- CH2N2 CH3CO2-

11. Draw the Lewis structures, give the molecular geometry, and determine whether the following will be polar or non-polar. Click on the arrow to check your answers

CCl4; CHCl3; CH2O; CO2