Chapter 7 Chemical Formulas and Chemical Compounds Ban

Chapter 7 - Chemical Formulas and Chemical Compounds

Ban Dihydrogen Monoxide! l l l Colorless, odorless, tasteless Kills uncounted thousands of people every year. Most deaths caused by accidental inhalation Prolonged exposure to its solid form causes severe tissue damage. Symptoms of ingestion can include l l l excessive sweating and urination, a bloated feeling, nausea, vomiting body electrolyte imbalance. For those who have become dependent, withdrawal means certain death.

Ban Dihydrogen Monoxide! l l l l l Also known as hydroxl acid Major component of acid rain Contributes to the "greenhouse effect. " May cause severe burns. Contributes to the erosion of our natural landscape. Accelerates corrosion and rusting of many metals. May cause electrical failures and decreased effectiveness of automobile brakes. Been found in excised tumors of terminal cancer patients. Is now an ingredient in most foods and beverages

Ban Dihydrogen Monoxide! Based on the evidence presented in the previous two slides, do you support the banning of dihydrogen monoxide? l Write at least two sentences stating your reasoning. l Please sign the petition! l

What is Dihydrogen Monoxide?

Chemical Formulas l Indicate the relative number of atoms or ions of each kind in a chemical compound 8 C atoms C 8 H 18 1 Mg 2+ ion Mg. Cl 2 1 Ca 2+ ion Ca(OH)2 18 H atoms 2 Cl- ions 2 OH- ions

Monatomic Ions formed from a single atom l Usually have noble gas configurations l That’s how we determine its charge l Example: l l Li: 1 s 22 s 1 l Li+: 1 s 2 or [He] l Table on p. 221 on monatomic ions

Naming Monatomic Cations Use the element’s name! l Yes, it’s that simple! l Example: l l Cs+ = cesium l Al 3+ = aluminum

Naming Monatomic Anions Drop the ending of the element’s name l Add the ending –ide l Examples: l l Cl- = chloride l N 3 - = nitride

Naming Monatomic Ions K+ l S 2 l Rb+ l O 2 l Il Ba 2+ l Cu+ l potassium l sulfide l rubidium l oxide l iodide l barium l copper l

Binary Ionic Compounds composed of two ions l Total numbers of positive charges and negative charges must be equal l Examples: l l Na. Cl l KBr l Ca. F 2

Writing Binary Ionic Compounds l Write the symbols for the ions side by side. Write the cation first. Al 3+ O 2 l Cross over the charges to use as the subscript for the other ion. Al 3+ O 2 Al 2 O 3

Writing Binary Ionic Compounds l Check the subscripts and divide them to give the smallest whole number ratio of ions. Al 2 O 3 l Write the formula! Al 2 O 3

Writing Binary Ionic Compounds Zinc iodide l Barium fluoride l Lithium oxide l Calcium oxide l Magnesium bromide l Zn. I 2 l Ba. F 2 l Li 2 O l Ca. O l Mg. Br 2 l

Naming Binary Ionic Compounds Give name of cation first l Then name the anion l Al 2 O 3 l l Name of cation: aluminum l Name of anion: oxide l Name of compound: aluminum oxide

Naming Binary Ionic Compounds Ba. I 2 l Zn. F 2 l K 2 O l Mg. O l Ca. Br 2 l Barium iodide l Zinc fluoride l Potassium oxide l Magnesium oxide l Calcium bromide l

Cations With Different Charges l Some elements form two or more cations with different charges l Fe 2+ and Fe 3+ l Iron (II) and Iron (III) l Naming compounds l Fe. O and Fe 2 O 3 l Iron (II) oxide and Iron (III) oxide

Name the Following Compounds Cu. O l Co. F 3 l Sn. I 4 l Fe. S l Copper (II) oxide l Cobalt (III) fluoride l Tin (IV) iodide l Iron (II) sulfide l

Quiz- Name the Following Compounds 1. 2. 3. 4. 5. K 2 S Ag. Br Na 2 O Fe. Cl 2 Ba. S 6. 7. 8. 9. 10. Lithium fluoride Silver iodide Iron (III) oxide Magnesium iodide Gold chloride

Polyatomic Ions that contain two or more atoms l Most are negatively charged l List of polyatomic ions is on handout l l **MEMORIZE l THEM!!!** Examples: l CN- cyanide l HCO 3 - hydrogen carbonate (bicarbonate) l NH 4+ ammonium

Polyatomic Ions l You will need to memorize the following: l l l l l Ammonium Acetate Hydroxide Nitrite Nitrate Bicarbonate Chromate Sulfate Phosphate NH 4+1 C 2 H 3 O 2 -1 OH-1 NO 2 -1 NO 3 -1 HCO 3 -1 CO 3 -2 Cr. O 4 -2 SO 4 -2 PO 4 -3

Oxyanions Polyatomic ions that contain oxygen l Name depends on number of oxygen atoms l

Oxyanions (cont. ) l If two oxyanionsl Most oxygens: -ate l Least oxygens: -ite l Example l NO 3 - : nitrate l NO 2 - : nitrite

Oxyanions (cont. ) l If more than two oxyanions l l l Most oxygens: “Per- …. –ate” “-ite” Least oxygens: “Hypo- …. –ite” Example l l Cl. O 4 - : perchlorate Cl. O 3 - : chlorate Cl. O 2 - : chlorite Cl. O- : hypochlorite

Polyatomic Ion Quiz Sodium hypochlorite l Potassium sulfate l Magnesium peroxide l Ammonium chloride l Lithium nitrate l Potassium phosphate l Na. Cl. O l K 2 SO 4 l Mg. O 2 l NH 4 Cl l Li. NO 3 l K 3 PO 4 l

Polyatomic Ion Quiz 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Bicarbonate Acetate Bisulfite Permanganate Nitrite Cyanide Hydroxide Bisulfate Nitrate What’s your favorite polyatomic ion?

Binary Molecular Compounds Composed of molecules (covalently bonded!) l A nonmetal bonded to another nonmetal l Examples: l l SO 3 l ICl 3 l CH 4 l H 2 O

Prefixes for Naming Binary Molecular Compounds l l l l l 1 2 3 4 5 6 7 8 9 10 monoditritetrapentahexaheptaoctanonadeca

Naming Binary Molecular Compounds l Which element goes first? l l Second element l l Smaller group number If same group- greater period number Use prefix only if there is more than one atom Prefix indicating number of atoms + root of the name of the element + -ide General order of elements in binary compounds: l C, P, N, H, S, I, Br, Cl, O, F

Naming Binary Molecular Compounds l Examples: l SO 3 – sulfur trioxide l Br. Cl 3 – bromine trichloride l PBr 5 – phosphorus pentabromide l N 2 O 5 – dinitrogen pentoxide

Naming Binary Molecular Compounds N 2 O l CCl 4 l NO l CO 2 l N 2 O 3 l P 4 O 10 l Dinitrogen monoxide l Carbon tetrachloride l Nitrogen monoxide l Carbon dioxide l Dinitrogen trioxide l Tetraphosphorus decoxide l

Naming Binary Molecular Compounds- More Practice! Disulfur dioxide l Silicon tetrafluoride l Sulfur monoxide l Phosphorus trioxide l Boron trifluoride l Diphosphorus pentoxide l S 2 O 2 l Si. F 4 l SO l PO 3 l BF 3 l P 2 O 5 l

Acids l Acid- a type of molecular compound l Two types Binary acids- made up of two elements- hydrogen, and one of the halogens (F, Cl, Br, I) l Oxyacids- contain hydrogen, oxygen, and a third element l l Examples l Binary acids: l l HCl- hydrochloric acid; HF- hydrofluoric acid Oxyacids: l l H 2 SO 4: sulfuric acid HNO 3: nitric acid

Formula Mass The sum of the atomic masses of all atoms represented in its formula l Units = amu (atomic mass units) l Example: What is the formula mass of water? l l 2 H atoms @ 1. 01 amu each = 2. 02 amu l 1 O atom @ 16. 00 amu each = 16. 00 amu l Total mass of water = 16. 00 + 2. 02 = 18. 02

Formula Mass l Find the formula mass of the following: l KCl. O 3 l H 2 SO 4 l Mg(NO 3)2 l C 12 H 22 O 11

Molar Mass The mass in grams of one mole of a substance l If we have 1 mole of H 2 O, we have l l 2 moles of H atoms l 1 mole of O atoms

Molar Mass (cont. ) l How many moles of each atom are in the following? l Ca. Cl 2 l Na. OH l KMn. O 4 l NH 4 OH l Mg(NO 3)2

Molar Mass (cont. ) Once we know the number of moles of each atom, we can calculate the molar mass. l In H 2 O: l l 2 moles H x 1. 01 g H = 2. 02 g H 1 mole H l 1 mole O x 16. 00 g O = 16. 00 g O 1 mole O

Molar Mass (cont. ) l Total mass of 1 mole H 2 O l 2. 02 g + 16. 00 g = 18. 02 g/mol

Molar Mass (cont. ) l Determine the molar mass of the following: l Ca. Cl 2 l Na. OH l KMn. O 4 l NH 4 OH l Mg(NO 3)2

Molar Mass as a Conversion Factor Can use molar mass as a conversion factor to determine number of moles l How many moles of H 2 O are in 34. 32 g? l

Molar Mass as a Conversion Factor l How many molecules of Na. Cl can be found in a sample containing 45. 43 g?

Molar Mass as a Conversion Factor l How many carbon atoms are in a 23. 43 g sample of CO 2?

Fun With Conversions! l Ibuprofen, C 13 H 18 O 2, is the active ingredient in Advil. l Find its molar mass l If the tablets in the bottle contain a total of 33 g of ibuprofen, how many moles of ibuprofen are in the bottle? l How many molecules of ibuprofen are in the bottle? l What is the total mass in grams of carbon in 33 g of ibuprofen?