Summer Work. Grade 7 American Program. Table of Contents

Transcription

1 Summer Work Grade 7 American Program Table of Contents Part I Structure of the Atom Pages 1 3 Part II Chemical Reactions Pages 4 7 Part III Chemical Bonding Pages 8 10 Part IV Organic Chemistry Pages Part V Electrochemistry Pages 14 16

2 Part I Structure of the Atom First Exercise: Read the following information on structure of the atom. Fill in the blanks where necessary. 1. The 3 particles ofthe atom are: a. b. c. 2. Their respective charges are: a. b. c. 3. The number of protons in one atom of an element determines the atom s, and the number of electrons determines of an element. 4. The atomic number tells you the number of in one atom of an element. It also tells you the number of in a neutral atom of that element. The atomic number gives the identity of an element as well as its location on the Periodic Table. 5. No two different elements will have the atomic number. 6. The of an element is the average mass of an element s naturally occurring atom, or isotopes, taking into account the of each isotope. 7. The of an element is the total number of protons and neutrons in the of the atom. 8. The mass number is used to calculate the number of in one atom of an element. In order to calculate the number of neutrons you must subtract the from the. Second Exercise: Give the symbol and number of protons in one atom of: Lithium Iron Bromine Copper

3 Oxygen Krypton Mercury Helium Third Exercise: Give the symbol and number of electrons in a neutral atom of: Uranium Boron Antimony Chlorine Iodine Xenon Fourth Exercise: Give the symbol and number of neutrons in one atom of: Show your calculations. Barium Carbon Fluorine Europium Bismuth Hydrogen Magnesium Mercury Fifth Exercise: Name the element which has the following numbers of particles: electrons, 29 neutrons, 26 protons protons, 74 neutrons 3. 2 electrons (neutral atoms) protons electrons, 125 neutrons, 82 protons (charged atom) 6. 0 neutrons

4 Sixth Exercise: Fill in the following table: Name Symbol Z A #p #e #e Atomic representation Na 17 Potassium P Iron 53 Silver 36 Seventh Exercise: Approximately 75% of the chlorine atoms found in nature have a mass of 35. The other 25% have a mass of 37.Whatshould we report as the average atomic weight for chlorine? Eighth Exercise: Suppose that a new element (E) were discovered that existed as three natural isotopes. 25% ofthe atoms had a mass of 278, 38% had a mass of 281, and the remainder had a mass of 285. What would be listed as the atomic weight of this element?

5 Ninth Exercise: Consider 200 grams of H2SO4. Calculate the number of moles present in this mass, as well as the number of molecules. M(H)=1g/mol M(O)=16g/mol M(S)=32g/mol Part II Chemical Reactions: First Exercise: Balance the following reactions: 1. NaBr + Ca(OH) 2 CaBr 2 + NaOH 2. NH 3 + H 2 SO 4 (NH 4 ) 2 SO 4 3. C 5 H 9 O + O 2 CO 2 + H 2 O 4. Pb + H 3 PO 4 H 2 + Pb 3 (PO 4 ) 2 5. Li 3 N + NH 4 NO 3 LiNO 3 + (NH 4 ) 3 N 6. HBr + Al(OH) 3 H 2 O + AlBr 3

6 Second Exercise: Indicate which type of chemical reaction (synthesis, decomposition, singledisplacement, double-displacement or combustion) is being represented in the reactions below: 1. Na 3 PO KOH 3 NaOH + K 3 PO 4 Reaction Type 2. MgCl 2 + Li 2 CO 3 MgCO LiCl Reaction Type 3. C 6 H O 2 6 CO H 2 O Reaction Type 4. Pb + FeSO 4 PbSO 4 + Fe Reaction Type 5. CaCO 3 CaO + CO 2 Reaction Type 6. P O 2 2 P 2 O 3 Reaction Type 7. 2 RbNO 3 + BeF 2 Be(NO 3 ) RbF Reaction Type 8. 2 AgNO 3 + Cu Cu(NO 3 ) Ag Reaction Type 9. C 3 H 6 O + 4 O 2 3 CO H 2 O Reaction Type C 5 H 5 + Fe Fe(C 5 H 5 ) 2 Reaction Type 11. SeCl 6 + O 2 SeO 2 + 3Cl 2 Reaction Type MgI 2 + Mn(SO 3 ) 2 2 MgSO 3 + MnI 4 Reaction Type 13. O 3 O. + O 2 Reaction Type NO 2 2 O 2 + N 2 Reaction Type Third Exercise: For the reaction below, which change would cause the equilibrium to shift to the right? CH 4 (g) + 2H 2 S(g) CS 2 (g) + 4H 2 (g) (a) Decrease the concentration of dihydrogen sulfide.

7 (b) Increase the pressure on the system. (c) Increase the temperature of the system. (d) Increase the concentration of carbon disulfide. (e) Decrease the concentration of methane. Fourth Exercise: Predict the effect of decreasing the volume of the container for each equilibrium. (a) 2H 2 O(g) + N 2 (g) 2H 2 (g) + 2NO(g) (b) SiO 2 (s) + 4HF(g) SiF 4 (g) + 2H 2 O(g)

8 (c) CO(g) + H 2 (g) C(s) + H 2 O(g) Fifth Exercise: Complete the following chart on page 7 by writing left, right or none for equilibrium shift, and decreases, increases or remains the same for the concentrations of reactants and products, and for the value of K. N 2 (g) + 3H 2 (g) 2NH 3 (g) kcal Stress Equilibrium Shift Concentration of N 2 Concentration of H 2 Concentration of NH 3 Add N 2 Add H 2 Add NH 3 Remove N 2 Remove H 2 Remove NH 3 Increase Temperature Decrease Temperature Increase Pressure Decrease Pressure

9 Part III Chemical Bonding: First Exercise: Bonding of NaCl 1. Fill in the Lewis dot symbols for Na (11) and Cl (17), below, and complete the shorthand electron configuration for each: Na Cl s s p 2. Now allow each atom to complete its octet, by losing or gaining electrons. Then write the shorthand electron configuration for each ion and its charge. Na Cl 3. Show the formation of the bond. Indicate its type. Second Exercise: Show the transfer of electrons between the following atoms to form cations and anions, and show the bond, in addition to indicating its type. a) K (19) and S (16) b) O (8) and Ba (56)

10 Third Exercise: Label "i" (ionic) or "c" (covalent) the bonds in the following compounds. 1. CO 2 2. Na 2 O 3. SF 2 4. N 2 O 5. CaO 6. Na 2 CO 3 Fourth Exercise: Answer the following multiple choice questions by choosing the correct letter. 1) How many electrons are shared in a single covalent bond? 1. A) 2 B) 3 C) 8 D) 1 E) 4 2) How many electrons are shared in a double covalent bond? 2. A) 3 B) 6 C) 8 D) 2 E) 4 3) How many unshared pairs of electrons does the nitrogen atom in 3. ammonia possess? A) 1 B) 2 C) 4 D) 5 E) 3 4) How do atoms achieve noble-gas electron configurations in single 4. covalent bonds? A) Two atoms share two electrons. B) Two atoms share two pairs of electrons. C) Two atoms share one electron. D) One atom completely loses two electrons to the other atom in the bond. 5) Why do atoms share electrons in covalent bonds? 5. A) to attain a noble-gas electron configuration B) to become ions and attract each other C) to become more polar D) to increase their atomic numbers

11 6) Which of the following is the name given to the pairs of valence 6. electrons that do not participate in bonding in diatomic oxygen molecules? A) outer pair B) unvalenced pair C) bound pair D) unshared pair E) inner pair 7) Which elements can form diatomic molecules joined by a single covalent bond? 7. A) hydrogen only B) halogens and members of the oxygen group only C) halogens only D) hydrogen, halogens, and members of the oxygen group E) hydrogen and the halogens only 8) A molecule with a single covalent bond is. 8. A) CO 2 B) CO C) Cl 2 D) N 2 9) A diatomic molecule with a triple covalent bond is. 9. A) O 2 B) F 2 C) N 2 D) H 2 10) Which of the following diatomic molecules is joined by a double 10. covalent bond? A) Cl 2 B) O 2 C) N 2 D) H 2 Fifth Exercise: Draw Lewis dot structures for the following compounds: CO 2 C 2 H 2 HCN

12 Part IV Organic Chemistry: First Exercise: Draw the complete structural formula and condensed molecular formula for each compound. IUPAC Name Complete Structural Formula Condensed Formula butane 2-methylhexane 3-ethyl-2-methylnonane propene ethyne 2-octyne cyclopropane 3-pentene

13 Second Exercise: Use IUPAC naming rules to name the following hydrocarbon compounds: CH 2 CH 3 a) CH 3 CH CH 2 CH CH CH 3 c ) CH C CH 3 CH 2 CH 3 CH 3 CH 3 H b) \ / C = C d) CH 3 -CH 2 -CH 2 -CH=CH-CH 3 / \ H CH 2 CH 3 e) f) g) h)

14 Third Exercise: Consider the following table of alkanes: Alkane Chemical Formula Melting Point ( o C) Boiling Point ( o C) Methane CH Ethane C 2 H Propane C 3 H Butane C 4 H Pentane C 5 H Hexane C 6 H Heptane C 7 H Draw the condensed formulas of all the above alkanes. 2. What is the general formula of alkanes? 3. How does the boiling point change with the increase in number of carbons? 4. How does the melting point change with the increase in number of carbons?

15 Part V Electrochemistry: First Exercise: Assign oxidation numbers to each of the atoms in the following compounds: CO 2 : O = C = CH 4 : H = C = HClO 4 O = H = Cl = MnO 2 O = Mn = SO 3 2- O = S = Second Exercise: Consider the following compounds: 1. Assign an oxidation state to each of the following nitrogen containing compounds: Formula Oxidation Number of N NH 3 NO 2 NO 3 - NH 2 OH N 2 H 4 2. Indicate the type of the following reaction according to N. Indicate the role of Nitrogen. N 2 (g) + 3 H 2 (g) 2 NH 3 (g)

16 Third Exercise: In each of the following reactions, assign oxidation numbers to all of the elements, identify the type of the reaction done by each element, and identify the oxidizing and reducing agents. a) 4 Fe + 3 O 2 2 Fe 2 O 3 b) Cr 2 O OH - 2 CrO H 2 O c) NH 4 NO 2 N H 2 O d) P Cl 2 4 PCl 5 e) 2 Cr 3+ + H 2 O + 6 ClO 3 - Cr 2 O ClO H +

17 Fourth Exercise: Consider the following galvanic cell. Answer the question on page 16. C. D. Anode Cathode B. F. 1. Complete the labeling the above diagram: A. B. C. D. E. F. G. 2. Write the half-reaction occurring at each electrode and indicate its type. Anode: type: Cathode: type: 3. What is the overall equation? 4. What is the charge of the anode? 5. What is the charge of the cathode?

18 6. The electrons flow from: a) Zn to Cu b) Cu to Zn 7. Give an example of a salt bridge, and indicate to which direction its ions will go?