take home qualitative chem sept 5, 2012

LSPU-LBC QUALITATIVE CHEMISTRY MIDTERM Name ____________________________________ Score/Grade _______________ BS FOOD TECH II-A Due: September 7, 2012 F;5-6 PM TAKE HOME EXAM A. Problem Set: 5 pts. Each number 1. A piece of silver mass 362 g has a heat capacity of 85.7 J/0C. What is the specific heat of silver? 2. A 6.22-kg piece of copper metal is heated from 20.5 0C to 324.3 0C. Calculate the heat absorbed (in kJ) by the metal. 3. Calculate the amount of heat liberated ( in KJ) from 366 g of mercury when it cools from 77.0 0C to 12.0 0C. B. Essay: 5 points each 1. Explain the thermochemical equation below: 4NH3 (g) + 5O2 (g) → 4NO (g) + 6H2O (g) ∆H = -905 J 2. In writing thermochemical equations, why is it important to indicate the physical state (that is, gaseous, liquid, solid, or aqueous of each substance? 3. State the Law of Energy Conservation. Give one example. 4. Differentiate spontaneous reaction and nonspontaneous reaction. C. Classification: 20 points: Write your answer in a tabular form 1. Identify the following reactions as Exothermic or Endothermic reactions.10 pts. evaporation of water making ice cubes melting solid salts burning sugar nuclear fission splitting a gas molecule apart mixing water and strong acid rusting of iron producing sugar by photosynthesis baking bread separating ion pairs condensation of rain from water vapor melting ice cubes forming ion pairs conversion of frost to water vapor 2. Which of the following processes are spontaneous and which are nonspontaneous.10 pts. a. Dropping of a bullet fired upwards b. Separation of water into hydrogen and oxygen by electrolysis c. Cooling of a hot flat iron d. Decay of animal wastes e. Mixing of gaseous carbon monoxide from car exhaust with air f. Boiling water g. Dissolution of salt in water h. Extraction of salt from seawater i. Rusting of iron j. Dissolving of sugar END Good Luck!