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Chemistry Final Review

Chemistry Final Review. Write the formula unit for Barium hydroxide. ans : Ba (OH) 2 2. Write the molecular formula for Trisulfur hexaoxide ans : S 3 O 6 3. How many moles are in 2.3 g of NaCl ans : 0.0396 moles 4. How many sig figs are in the answer in #3? ans : 3.

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Chemistry Final Review

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  1. Chemistry Final Review Write the formula unit for Barium hydroxide. ans: Ba(OH)2 2. Write the molecular formula for Trisulfurhexaoxide ans: S3O6 3. How many moles are in 2.3 g of NaCl ans: 0.0396 moles 4. How many sig figs are in the answer in #3? ans: 3

  2. 5. In the reaction of Na + S2 Na2S, write the molar ratio for Na/Na2S ans: 4:2 Na/S2 ans: 4:1 6. Given 5 g of sodium, how many grams of Na2S will be produced? ans: 8.48 g Na2S 7. How many sif fig are expressed in #6 answer? ans: 3

  3. 8. Concern the reaction between, Cu + NaCl What type of reaction may be represented? ans: single replacement Does this reaction form a produce? ans: No, Cu is less reactive than Na Would Cu replace Ag in AgCl2 ans: yes, Ag is less reactive than Cu

  4. 9. Given 2Mg + PbCl4 Pb + 2MgCl2 Is this a good reaction? ans: yes, Mg is more reactive than Pb How many mole of PbCl4 is needed to form 5.5 moles of MgCl2 ? ans: 11 moles MgCl2 How many grams of Mg is needed to produce 0.25 moles Pb? ans: 12 g Mg How many grams of MgCl2 is produced from 56.4 g PbCl4? ans: 30.6 g MgCl2

  5. How many moles are in 5.6 g of CuCl2? ans: 0.045 moles CuCl2 11. How many molecules of O2 is needed to burn 356 moles of CH4 ? ans: 4.29 x 1026 molecules O2 12. Given 5.6 x 1021 molecules of Cu(NO3)2, how many grams would you have? ans: 1.75 g Cu(NO3)2 • How moles are in 46 g C2H5OH? ans: 1 mole C2H5OH

  6. Given 12 ml of O2 in 2.5 L of water, which is the solute? ans: O2, of a lesser amount 15. A alloy is composed of 54% Cu and 46% Fe. Which is the solvent? ans: Cu, of a greater amount. • Oil will not mix in water. Oil is said to be: ans: immiscible in water • Is CaCO3 soluble in water? ans: insoluble

  7. What is the molarity of 0.45 mole of HCl in 35 ml of water? ans: 12.9 M HCl 19. How many grams of NaOH is needed to make 250 ml of 2 M NaOH? ans: 20 g NaOH • Given 54 g CaCl2 dissolved in 150 ml, what is the molar concentration? ans: 3.3 M 21. Is the [OH-] = 5.6 x 10-9 from a pH = 4.765 ans: no, pH = 5.75

  8. 22. What is the [H+] from [OH-] = 2.3 x 10-12 ans: 0.004 M 23. Is a solution with [OH-] = 8.3 x 10-2 an acidic or basic solution? ans: basic, pH = 12.9 24. What is the [H+] with a pH = 4.5 ans: [H+] = 3.16 x 10-5 25. What is the pOH when the pH = 8.9 ans: 14 – 8.9 = 5.1

  9. Is a solution basic or acidic with a hydrogen concentration of 1.2 x 10-10 ? ans: basic, pH = 9.9 27. Given a 6M HCl, what is the [H+] ? ans: HCl is strong, 100% dissociation making the [H+] = 6 M 28. What is the [H+] from pOH = 12.5 ans: 0.0316 29. What is the pH of the solution in #28? ans: pH = 1.5

  10. Given the weak acid of HA with a Ka = 1.6 x 10-5 : a. How much of the HA remains at equilibrium? ans: 0.25 – 0.002 = 0.248 b. What is the pH of HA? ans: pH = -log [H+] = 2.7 31. With an increase in the temperature, there will be an ___________ in reaction rate. ans: increase

  11. 32. A catalyst will increase reaction rate by: ans: lowering the activation energy 33. A substance that slows reaction rate by interfering with reaction pathways is called ans: inhibitor • A reduction in the concentration of a substance would tend to ___________ reaction rate? ans: slow or reduce

  12. 35. What is the formula unit for Iron (III) oxide? ans: Fe2O3 36. True or false: a molecular compound is composed of a metal bonded to a non-metal? ans: False, this defines an ionic compound • The sharing of electrons tends to form what type of bond? ans: covalent bond

  13. Which of the following are diatomic molecules: nitrogen, helium, argon hydrogen ans: N2 and H2 others are O2, F2, Cl2, Br2 and I2 39. How many atoms of chlorine are in Carbon tetrachloride? ans: 4 40. What is the name of AgF ? ans: Silver (I) fluoride, MUST include Roman numeral with transisitional metal naming.

  14. 41. Name Cr(ClO4)4 ans: Chromium (IV) perchlorate 42. With ionic compounds a Roman numeral is used to identify the number of atoms present. In a molecule _______ is used to identify the number of atoms in a molecule. ans: prefix 43. What is the prefix for 6 anshexa- 44. The prefix penta- means? ans: 5

  15. 45. Name the given compounds: a. HBr ans: hydrobromic acid b. H2SO3 ans: sulfurous acid c. HClO4 ans: perchloric acid d. HF ans: hydrofluoric acid

  16. 46. Write the formula for the following: a. Calcium hydroxide ans: Ca(OH)2 b. Hydrosulfuric acid ans: H2S c. Chlorous acid ans: HClO2 d. Oxalic acid ans: H2C2O4

  17. 47. Identify the type of reaction and complete: a. CH4 + O2 ans: combustion, CH4 + 2O2  CO2 + 2H2O b. NaNO3 + Fe(SO4)2  ans: Double replacement 4NaNO3 + Fe(SO4)2  2Na2SO4 + Fe(NO3)4 c. Pb + Ca(OH)2  ans: Single Replacement, but a check of the activity series indicate no reaction.

  18. 48. Would N2S5 tend to form ionic or covalent bonds? ans: Non-metal bonded to non-metal is covalent. 49. The further apart two element are place on the periodic table, the __________ ionic the bond between then will be. ans; more 50. What is the molar mass of potassium dichromate? ans: K2Cr2O7 has a mass of 294 g/mol

  19. 51. Food preservatives and weed killer are examples of: ans: an inhibitor 52. What affect would the increase in surface area have on reaction rates? ans: results in an increase 53. Energy based on position or composition is: ans: potential energy 54. The change in the amount of energy in a reaction is called: ans: enthalpy of the reaction

  20. What is the average reaction rate if at time 2s the concentration was 0.02 M and at time 12 s the concentration is at 0.01 M ans: -0.001 mole/L s 56. What does the (-) value indicate? ans: reduction in the [reactants] in time 57. The energy of motion is called: ans: kinetic energy 58. What concept is defined by mole solute/Kg solvent? ans: molality

  21. Colligative properties are boiling point elevation, vapor pressure lowering, osmotic pressure and _______________. ans: freezing point depression 60. A _______ is exhibited by the Tyndall Effect ans: colloid 61. Which dissociation will result in a great depression of the freezing point of water? NaCl or MgCl2 ans: MgCl2 breaks into 3 particles

  22. How much mass of water can absorb 4284 J of heat when the temperature changes from 20 oC to 38.2oC? ans: 56.3 g 63. How many joules of heat is exchanged when 156 g of a substance cools from 85.2oC to 5.6oC. The Cp = 0.554 J/goC ans: -6879.4 J 64. What does the negative value in #63 mean? ans: energy is loss by the substance to the surrounding.

  23. In the synthesis reaction of sodium in the present of molecular oxygen, what is the product? ans: Na2O 66. Will a precipitate form in the following reaction: Ca(NO3)2 + K2SO3 ans: Yes, CaSO3

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