Chemistry 105

Final

Write your name on all material to be turned in.  Answer 15 Questions. Everyon is required to do question 7.   Write all answers in your “Blue Book” and show all work in detail.  Partial credit will be given only if an answer is partially correct.  You may use your calculators and your reference material such as periodic table and formula sheets.  Formula sheets (1 page, front and back) are allowed, but NO OPEN BOOKS OR NOTES.

 

  1. Describe one difference between an element and a compound.  Name some of the physical properties of a substance.  How are physical properties different from chemical properties? 
  1. The metal Mercury melts at –39°C, which is equivalent to what on the Kelvin scale? What is that on the Farenheit scale?
  2. A silver ring has a mass of 10.51 grams.  When immersed in water the ring displaces 0.953 ml.  What is the density of silver? Report the answer in significant figures.
  3. You have 5.67 moles of sulfur. How many atoms are present? How many grams do you have?
  4. How many protons, neutrons, and electrons are present on a 2964Cu 2+ ion? How many protons and electrons are present on a neutral atom of Copper? 
  5. What is the empirical formula for a substance with the composition: Sodium(Na) 54%, Boron (B) 8.50%, Oxygen (O) 37.5%
  6. 2C3H8O + 9O2 ® 6CO2 + 8H2O       For the given balanced equation find the limiting reactant if you have 6 grams of C3H8O and 15 g of O2 .  How much leftover reactant ( in grams)  will you have.
  7. You need to prepare a 0.9 M solution of CsF salt.  How many grams are required for a 2 liter solution? How many for a 150 ml solution?
  8. You have a 0.9 M solution of CsF, but you need 0.05L of 0.0036M CsF for your experiment. How do you prepare what you need?
  9. Pb(NO3)2  + KI ® PbI2 + KNO3   Balance the equation.  Which are the precipitate and which are spectator ions? Write out the correct  net ionic equation for the reaction.
  10. Show the Lewis dot structure for each of the following elements:  Nitrogen, Carbon, Cesium, Bromine, Calcium
  11. Show the Lewis structure of Water, Ammonia, Carbon Dioxide, and C2H2 . Indicate lone pairs as appropriate.   
  12. Lindane, an insecticide has a formula weight of 290.85.  It has the following percent composition.  24.78% Carbon, 2.08% Hydrogen, 73.18% Chlorine.  Find the empirical and molecular formulas.  
  13. An ice cube (1500 grams) is removed from the freezer at a temperature of  269 Kelvin, and allowed to melt.  Room temperature is 313 Kelvin.  What quantity of heat was extracted from the room?
  14. What quantity of heat is required to convert 1500 grams of water at 100 oC to steam?
  15. The wavelength of a photon is 600 nanometers.  What is its frequency?  What is the energy of the photon?
  16. Show the electron configuration of an element with an atomic number 15. Show the electron configuration of an element with atomic number 37. 
  17. Write out a symbol for an ion which has 56 protons, 81 neutrons, 54 electrons.  Is it a cation or an anion?
  1. Balance the following skeletal equations:

 

    1. H2 + O2 ® H2O
    2. Mg + O2 ® MgO
    3. Fe + O2 ® Fe2O3
    4. C2H4 + O2 ® CO2 + H2O
    5. C10H10 + O2 ® CO2 + H2O

 

 

 

Dr. Falcone            Page 1    9/27/2004