Exam Tomorrow (R) 10-11:30 am Review/Problem Session Today, 11 am, SL 110

Oxo-acid Oxo-anion Hypo-chlorite ion ClO- hypochlorous acid HClO chlorate ion ClO3- chloric acid HClO3 perchloric acid HClO4 Per-chlorate ion ClO4-

What are the names of the following compounds? OF2 S4N4 BCl3 OF2 is oxygen difluoride S4N4 is tetrasulfur tetranitride BCl3 is boron trichloride

What are the formulas for the following binary molecular compounds? carbon disulfide nitrogen tribromide dinitrogen tetrafluoride The formula for carbon disulfide is CS2. The formula for nitrogen tribromide is NBr3. The formula for dinitrogen tetrafluoride is N2F4.

Bromine has an oxoacid, HBrO2, bromous acid (compare to HClO2, chlorous acid). What are the name and formula of the corresponding anion? The anion corresponding to HBrO2 is bromite, BrO2-.

Organic Compounds An important class of molecular substances; they contain carbon combined with other elements – notably hydrogen, oxygen, and nitrogen. Hydrocarbons contain only carbon and hydrogen.

A functional group is a reactive portion of a molecule that undergoes predictable reactions. Examples Name of Group Functional Group Methyl alcohol Alcohol Dimethyl ether Ether Acetic acid Carboxylic acid

A compound that contains water molecules weakly bound in the crystals. Hydrate A compound that contains water molecules weakly bound in the crystals. The formula of a hydrate is written with a dot before the water molecule(s) included. For example: CuSO45H2O

Hydrates are named using the anhydrous (without water) compound name followed by the prefix for the number of water molecules included and the word “hydrate.” For example: CuSO45H2O is named copper(II) sulfate pentahydrate.

A compound whose common name is green vitriol has the chemical formula FeSO47H2O. What is the chemical name of this compound? FeSO47H2O is iron(II) sulfate heptahydrate.

Calcium chloride hexahydrate is used to melt snow on roads Calcium chloride hexahydrate is used to melt snow on roads. What is the chemical formula of the compound? The chemical formula for calcium chloride hexahydrate is CaCl26H2O.

A chemical equation is the symbolic representation of a chemical reaction in terms of chemical formulas. For example: 2Na + Cl2  2NaCl Reactants are the starting materials; they are written on the left of the equation. Products are the materials at the end of the reaction; they are written on the right of the equation.

Because a reaction must accurately describe the chemical reaction, it must be consistent with the law of conservation of mass. When this is not the case, after correct formulas are written for each reactant and product, the coefficients are adjusted so that the same number of each atom is present in both the reactants and the products. This is called balancing the equation.

Figure 2.25: Representation of the reaction of methane with oxygen. Write a balanced chemical reaction for this combustion reaction. CH4(g) + 2 O2 (g) 2 H2 O(l) + CO2(g)

Balance the following equation: CS2 + O2  CO2 + SO2 Tally the number of each atom on each side: C 1 on reactant side; 1 on product side S 2 on reactant side; 1 on product side O 2 on reactant side; 4 on product side Begin by inserting the coefficient “2” before SO2 on the product side. We leave O2 until later because it is an element.

C 1 on reactant side; 1 on product side CS2 + O2  CO2 + 2SO2 Tally the atoms again: C 1 on reactant side; 1 on product side S 2 on reactant side; 2 on product side O 2 on reactant side; 6 on product side Insert a “3” before O2: CS2 + 3O2  CO2 + 2SO2

C 1 on reactant side; 1 on product side CS2 + 3O2  CO2 + 2SO2 Tally the atoms again: C 1 on reactant side; 1 on product side S 2 on reactant side; 2 on product side O 6 on reactant side; 6 on product side The reaction is now balanced!

Balance the following equation: NH3 + O2  NO + H2O Tally the number of each atom on each side: N 1 on reactant side; 1 on product side H 3 on reactant side; 2 on product side O 2 on reactant side; 2 on product side Begin by inserting the coefficient “2” before NH3 on the reactant side and the coefficient “3” before H2O on the product side. We leave O2 until later because it is an element.

N 2 on reactant side; 1 on product side 2NH3 + O2  NO + 3H2O Tally the atoms again: N 2 on reactant side; 1 on product side H 6 on reactant side; 6 on product side O 2 on reactant side; 4 on product side To balance N, insert a “2” before NO: 2NH3 + O2  2NO + 3H2O

2NH3 + O2  2NO + 3H2O Tally the atoms again: N 2 on reactant side; 2 on product side H 6 on reactant side; 6 on product side O 2 on reactant side; 5 on product side Since this gives us an odd number oxygens, we double the coefficients on NH3, NO, and H2O and to balance O, insert a “5” before O2.

The reaction is now balanced! Tally the atoms again to double check: 4NH3 + 5O2  4NO + 6H2O N 4 on reactant side; 4 on product side H 12 on reactant side; 12 on product side O 10 on reactant side; 10 on product side The reaction is now balanced!

Balance the following equation: C2H5OH + O2  CO2 + H2O Tally the number of each atom on each side: C 2 on reactant side; 1 on product side H 6 on reactant side; 2 on product side O 3 on reactant side; 3 on product side Begin by balancing H. Insert the coefficient “3” before H2O on the product side. We leave O2 until later because it is an element.

Tally the number of each atom on each side: C2H5OH + O2  CO2 + 3H2O Tally the number of each atom on each side: C 2 on reactant side; 1 on product side H 6 on reactant side; 6 on product side O 3 on reactant side; 5 on product side To balance C, insert a “2” before CO2.

Tally the number of each atom on each side: C2H5OH + O2  2CO2 + 3H2O Tally the number of each atom on each side: C 2 on reactant side; 2 on product side H 6 on reactant side; 6 on product side O 3 on reactant side; 7 on product side To balance O, insert a “3” before O2.

Tally the number of each atom on each side: C2H5OH + 3O2  2CO2 + 3H2O Tally the number of each atom on each side: C 2 on reactant side; 2 on product side H 6 on reactant side; 6 on product side O 7 on reactant side; 7 on product side The reaction is now balanced!

Polymer A very large molecule that is made up of a number of smaller molecules repeatedly linked together. Monomers The small molecules that are linked together to form a polymer.

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