Chem 105X Fri. Sept. 17, True 2. False. Dihydrogen monoxide is toxic. Today

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1 Chem 105X Fri. Sept. 17, 2010 Today Written homework problem #1 Handed back #2 Due Monday in class Next week s lab 0% 0% 1) Formulas and names 2) Mixed nomenclature 3) Calculations: moles-atoms-molecules, and all that True False Dihydrogen monoxide is toxic. 1. True 2. False /17/2010 1

2 10 Results from Homework Problem #1 Most common error tagging on units of atoms in the answer, without it appearing first in (the numerator of) the work leading up to the answer. About 1/3 of the papers actually used the recommended unit conversion factor method. In the long run this is the best way to solve many practical science and engineering problems /17/2010 2

3 Laboratory next week Introduction to Measurement Glassware and Use of Excel for Numerical Analysis Go to the Blackboard Course Documents for your lab procedure and pre-lab and lab report form. 9/17/2010 3

4 Name of element Monatomic ion charges Root of element+ ide Name of element + (I) or (II) to /17/2010 4

5 Naming Ionic Compounds Name Formula Formula Name 9/17/2010 5

6 Naming Ionic Compounds Cation name first..anion name second Names DO NOT reflect the relative numbers The relative numbers are INFERRED from the ION CHARGES Transition metals and Sn,Sb,Pb,Bi require ROMAN NUMERAL to indicate charge Zinc (Zn) does NOT require a roman numeral it is always 2 + NaF sodium fluoride K 2 O potassium oxide lithium nitride Li 3 N CoI 2 cobalt (II) iodide ZnI 2 zinc iodide 9/17/2010 6

7 OWL and the text differ on name of the Ni 2+ ion. Kotz calls it nickel (II) OWL calls it just nickel (because this is essentially the only ion formed by Ni) On exams, if Ni is used, the charge will be specified, and EITHER NAME will be an acceptable answer. 9/17/2010 7

8 Polyatomic ions - like a molecule, but with total charge > or < 0. All but two contain O, so they are called oxoanions NH + 4 OH - (hydroxide) NO - 2 (nitrite) NO - 3 (nitrate) ClO - (hypochlorite) ClO - 2 (chlorite) ClO - 3 (chlorate) ClO - 4 (perchlorate) CN - (cyanide) CH 3 CO - 2 (acetate) MnO - 4 (permanganate) HCO - 3 (hydrogen carbonate) HSO - 4 (hydrogen sulfate) H 2 PO - 4 (dihydrogen phosphate) CO 2-3 (carbonate) SO 2-3 (sulfite) SO 2-4 (sulfate) CrO 2-4 (chromate) Cr 2 O 2-7 (dichromate) HPO 2-4 (hydrogen phosphate) PO 4 3- (phosphate) 9/17/2010 8

9 You need to KNOW NAMES and FORMULAS of the polyatomic ions on previous table. This is your chemistry vocabulary. Table 2.4 p. 74 And Oxoanion Table on the course website. 9/17/2010 9

10 Ionic compounds with polyatomic ions Need to RECOGNIZE THE ION(s) FROM THE TABLE within the formula. NaNO 2 contains one Na + and one NO 2 - (nitrite) ion per formula unit. NH 4 NO 2 contains one NH 4+ (ammonium) and one NO 2- ion per formula unit. 9/17/

11 Calcium phosphate (on board) (Always) Ca 2+ (Always) PO 4 3- Balance charge using lowest integer ratio: 3:2 Ca 3 (PO 4 ) 2 9/17/

12 Names include Roman numerals for transition and lower main group atoms (but not zinc). Iron (III) nitrite (Always) Fe 3+ (Always) NO 2 - Balance charge using lowest integer ratio: 1:3 Fe (NO 2 ) 3 9/17/

13 REQUIRED Copper (I) hydrogen carbonate Or Copper (I) bicarbonate Therefore, this must be the Cu + cation HCO 3- anion CuHCO 3 9/17/

14 1 mole of iron (II) sulfate contains how many moles of iron? 1. two 2. three 3. four 4. One 7% 0% 0% 93% two three four One 9/17/

15 The formula of the compound calcium chlorite is CaCl 64% 2. CaCl 2 3. CaClO 2 14% 19% 4. Ca(ClO 2 ) 2 4% CaCl CaCl2 CaClO2 Ca(ClO2)2 9/17/

16 Binary (2-element) covalent compounds 9/17/

17 Covalent compounds are formed by non-metal elements. 9/17/

18 Binary Covalent compounds - contain 2 elements. The relative number of atoms is in general NOT PREDICTABLE. So we just work back and forth between name and formula. Names: DO INCLUDE PREFIX REFLECTING No. of atoms. The 2 nd atom is named like the monatomic ion (but its not an actual ion in the molecule ) CO CO 2 C 2 O 2 C 3 O 2 etc Carbon monoxide Carbon dioxide Dicarbon dioxide Tricarbon dioxide The element to RIGHT on the periodic table goes 2 nd. 9/17/

19 Mixed nomenclature Detecting covalent vs. ionic compounds OWL 2.8c 9/17/

20 No metal or NH 4! Therefore covalent What is the name of the compound with the formula SO 3? Sulfur trioxide What is the name of the compound with the formula KNO 3? Group I metal is ALWAYS 1+! Therefore ionic. Potassium nitrate What is the formula for nickel chloride? This transition metal is ALWAYS 2+! Therefore ionic. What is the formula for boron trichloride? No metal or NH 4! Therefore covalent NiCl_2_ BCl_3_ 9/17/

21 Moles and atoms calculations 9/17/

22 Molar mass (also called molecular weight) Molar mass = Sum of atomic weights of all atoms in formula = mass of 1.00 mole of the compound Units: grams/mole (abbreviated g/mol) Molar mass of lithium hydrogen phosphate =? Li 2 HPO 4 M(Li 2 HPO 4 ) = 2(6.941g/mol) g/mol g/mol + 4(15.999g/mol) M(Li 2 HPO 4 ) = g/mol 9/17/

23 Practice problem using mole and molar mass 9/17/

24 Acetonitrile, CH 3 CN, is present in the tail of Comet Hale-Bopp. How many moles of acetonitrile ( AN ) is contained in 2.50 kg AN? H On board initial data... = final H C C N H g/mol 2.50 kg AN =? moles AN moles AN 2.50 kg AN =? moles AN kg AN 1mole AN 2.50kg AN =? moles AN kg AN g AN The molar mass 9/17/

25 1mole AN 2.50kg AN =? moles kg AN g AN AN g AN 1mole AN 2.50kg AN =? moles kg AN g AN AN The metric conversion factor g AN 1mole AN 2.50kg AN = moles kg AN g AN AN 60.9 moles 9/17/ AN

26 The End 9/17/