Chemistry 200 Exam 1 Review Problems 1. Calculate the number of atoms in 10. 0 grams of Fe. 2. Give the mass number, #protons, #neutrons and #electrons for the isotope strontium-88. 3. Calculate the number of moles of carbon in 50. 0 g of benzene C6H6 4. A substance is found to be 38. 7 % C, 9. 7 % H and 51. 6 % O by mass. Its molar mass is 62. 1 g/mole. What is its molecular formula? 5. Name the following: a) Ca(OH)2b) KCN c) HClO4(aq)d) FeSO4e) Na2O f) SF6g) MgSO4 ( 2H2Oh) Na2O2 6. What are the formulas of the following compounds? ) sodium sulfite b) potassium permanganatec) calcium sulfide d) aluminum hydroxidee) mercury (II) phosphate f) tetraphosphorus trisulfideg) nitrous acid 7. Which of the following is not an example of a chemical change? a) converting gasoline to carbon dioxide and water b) digesting starch to give glucose c) grinding sucrose crystals into powdered sugar d) smoking tobacco e) generating carbon dioxide from baking soda and vinegar 8. The density of ethyl alcohol is 0. 789 g/mL. What is the volume of 35. 5 grams of ethyl alcohol ? 9. How many significant figures are in the mass measurement 0. 50 gram? 10. If an automobile engine has a volume of 155 in3, what is the volume in cm3 ? (2. 54 cm = 1 in exactly) 11. Convert 25 ? L into milliliters 12. If 5. 58 g of powdered iron react with powdered sulfur to produce 8. 79 g of iron sulfide, what is the mass of reacting sulfur? 13. Sodium chloride, table salt, melts at 801°C. What is the melting point on the Fahrenheit scale ? 14. Express this number in scientific notation: 0. 00104 centimeter 15. What is the mass in kilograms of a beaker that weighs 101 grams? 16. Convert 12 g(cm2/s2 to Joules (kg(m2/s2) 17. A 1. 13 g sample of a hydrate, ZnSO4 ( X H2O is dissolved in pure water and the sulfate ion is precipitated by adding an excess of barium chloride solution. The mass of pure dry barium sulfate obtained is 0. 8223 g. What is the formula of the zinc hydrate? 18. 0. 01981 g of an acid containing only C, H, and O undergoes combustion to yield 0. 04198 g carbon dioxide and 0. 00645 g water. What is the empirical formula of the acid? 19. The maximum allowable concentration of carbon monoxide in urban air is 10 mg/m3 over an eight-hour period. At this level, what mass of CO in grams is present in a room measuring 8. x 12. 0 x 20. 0 ft ? 20. An English unit used in pharmaceutical work is the grain (gr). There are 15 grains in 1 gram. An aspirin tablet contains 5. 0 gr of aspirin. A 145 lb person takes two aspirin tablets. Calculate the dosage of aspirin, which is the number of milligrams of aspirin per kilogram of body weight. (1 lb = 453. 5 g) 21. The dosage of an arthritis medicine for dogs is given as 1. 5 – 1. 7 mg / kg body weight. If my dog weighs 70. lbs, and the drug comes as 100 mg tablets, how many tablets should my dog get? (1 lb = 453. 5 g) True or False 22.
A compound is a pure substance that cannot be broken down any further by ordinary chemical reaction. 23. Li2O is dilithium oxide. 24. The nucleus of one atom of 18O contains 18 neutrons and 8 protons. 25. The name of the family of potassium is “alkali metal”. 26. Sodium chloride is a mixture. 27. All atoms of an element have the same mass. More Calculations: 28. Given the reaction:2C2H6 + 7O2 ( 4CO2 + 6H2O How many moles of O2 will react completely with 12. 00 moles of C2H6 ? 29. Given the equation:4FeS2 + 11O2 ( 2Fe2O3 + 8SO2 If you react 85 grams of FeS2 with excess O2 , how many grams of Fe2O3 should you get? 0. Given the reaction: 2C2H6 + 7O2 ( 4CO2 + 6H2O If 28. 0 grams of C2H6 are reacted with excess oxygen, and 70. 0 grams of CO2 are produced , what is the percent yield of the reaction? 31. Given the reaction: 2 H2 + O2 ( 2 H 2O If 15. 0 g of H2 are mixed with 15. 0 g of O2 what mass of water is produced? 32. What is the molarity of a HCl(aq) solution made by dissolving 0. 20 moles of HCl(g) in enough water to make 40. 0 mL of solution? 33. What mass of NaOH(s) is required to prepare 250 mL of 50. 0 mM NaOH(aq)? (note: what does mM (millimolar) mean? 34. How many mL of 12 M HCl(aq) do you need to prepare 150. 0 mL of 1. 5 M HCl(aq)? 35. If 75. 0 g of Na2SO4 are dissolved in water to make 1. 50 L of solution, what are the concentrations (molarity) of all the ions in the final solution? 36. If 0. 203 g of KHP (potassium hydrogen phthalate) is titrated with 10. 7 mL of NaOH (aq) , what is the molarity of the NaOH solution? (molar mass KHP = 204. 22) KHP + NaOH ( H2O + salt 37. Given the following equation: 3 NiSO4 (aq) + 2 Na3PO4 (aq) ( Ni3(PO4)2 (s) + 3 Na2SO4 (aq) How many mL of 0. 75 M NiSO4 (aq) are needed to react completely with 35. 6 mL of 0. 265 M Na3PO4 (aq)? 38. Element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. The average atomic mass of the element is __________ amu. [pic] 39. Provide the products of the following reaction: C6H10 + O2 > What type of reaction is this? 40. Given the following equation: 3 NiSO4 (aq) + 2 Na3PO4 (aq) ( Ni3(PO4)2 (s) + 3 Na2SO4 (aq) If 20. 0 mL of 0. 100 M NiSO4 is reacted with 35. 0 mL of 0. 100 M Na3PO4 how many grams of Ni3(PO4)2 are produced?