Name:  __________________________
			Worksheet # 4 Quarter 4 Packet 3
	Power Bonds 1. Draw a Lewis structure for each of the molecular substances in the table below.  Remember that some of the molecules may contain a multiple bond.  Molecule           Bond Energy of 1 Bond in                           Molecule (kJ/mol) C2H6                 347 C2H4                 614 C2H2                 839 CH2O                799 2.  Name each molecule.  What does kJ/mol stand for? 3. The bond energies listed in the table of the first three molecules refer to the amount of every needed to break each molecule's carbon-carbon bond.  What relationship exists between the type of bond and the bond strength? 4. The forth molecule in the table, formaldedhyde (CH2O), contains a carbon-oxygen bond.  The bond energy listed for formaldehyde is the amount of energy needed to break the carbon-oxygen bond in this molecule.  What type of bond exists between these two atoms? 5.  The bond length for several bonds is given in the table below.  What can your say about the relationship between bond length and bond energy? Type of Bond             Bond Length C (double bond) C          134 pm C  (triple bond) C          120  pm C  (double bond) O         123 pm C  ( single bond ) C         150 pm 6.  What metric unit is a pm and it is equal to how many m?
		Identifying Hydrates Mr. Schuett was asked to determine the formulas of three sulfate (SO4) hydrates of transition metals.  First he found the mass of each solid hydrate sample.  Then he heated each hydrate gently for 10 minutes to remove the water.  The sample were allowed to cool for 30 minutes and then reweighed.  The results of the experiment are listed in the table below. Sample  Mass before  Mass after   Mass of water   Percent water  Ratio of water              Heating (g)   Heating (g)  in Hydrate (g)   in hydrate       molecules to                                                                                                    metal ion 1          250                160              (               )     (               )        5:1 2          223                151              (               )     (               )        4:1   3          281                155              (               )     (               )        7:1  1. Calculate the mass of water in each of the unknown hydrates.   2. Chemists often discuss hydrates in terms of the percent water in the hydrate.  Calculate the percent water in each of the hydrates using this formula: Percent water =  mass water / mass hydrate 3. Magnesium sulfate forms a hydrate that has seven water molecules for each magnesium ion.  The formula of this hydrate is MgSO4 (dot) 7H2O.  The name of the hydrate is magnesium sulfate heptahydrate.  Knowing this, complete the formulas below for each of the hydrate samples. Sample 1: CuSO4 (dot) __________________ Sample 2: MnSO4 (dot)__________________ Sample 3: NiSO4 (dot)___________________ 4. Name the three hydrates in this experiment.