chapter 7 chemical formulas and … 7.1 and 7.2 day1 chemical names and formulas ... list the rules...
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CHAPTER 7 CHEMICAL FORMULAS AND CHEMICAL COMPOUNDS
SECTION 7.1 AND 7.2 DAY1 CHEMICAL NAMES AND FORMULAS
Objectives: ¢ Explain the significance of a chemical formula. ¢ Determine the formula of an ionic compound
formed between 2 given ions. ¢ Name an ionic compound given its formula. ¢ Using prefixes, name a binary molecular
compound from its formula. ¢ Write the formula of a binary molecular
compound given its name.
OBJECTIVES CONTINUED
¢ List the rules for assigning oxidation numbers. ¢ Give the oxidation number for each element in
the formula of a chemical compound. ¢ Name binary molecular compounds using
oxidation numbers and the Stock system.
OXIDATION NUMBERS
¢ What is the charge on the bromide ion in NaBr? ¢ Charges are physically real; oxidation numbers
are just for bookkeeping to help keep track of electrons.
OXIDATION NUMBERS (IN YOUR TEXTBOOK)
¢ Number precedes the sign
¢ Example: 2+
¢ Sign precedes the number
¢ Example: +2
Ionic charge Oxidation number
OXIDATION NUMBERS Assigning oxidation numbers: 1. Atoms in a pure element have an oxidation number of zero. 2. The more-electronegative element in a binary molecular
compound is assigned the number equal to the negative charge it would have as an anion. The less-electronegative atom is assigned the number equal to the positive charge it would have as a cation.
3. Fluorine has an oxidation number of -1. 4. Oxygen has an oxidation number of -2. (except in peroxides
in which it is -1 --- H2O2 and in compounds with halogens in which it is +2 --- OF2)
5. Hydrogen has an oxidation number of +1. (except in compounds with metals in which it is-1)(CH4)
6. In a compound, the sum of the oxidation numbers will equal zero.
7. The sum of the oxidation numbers of all atoms in a polyatomic ion is equal to the charge of the ion.
OXIDATION NUMBERS
Assign oxidation numbers to each of the following compounds:
a. UF6
b. H2SO4
c. MgCl2
OXIDATION NUMBERS
Assign oxidation numbers to each atom in the following compounds or ions:
a. HCl b. CF4
c. PCl3
d. SO2
e. HNO3
f. KH g. P4O10
h. HClO3
i. N2O5
j. GeCl2
SECTION 7.1 CHEMICAL NAMES AND FORMULAS
¢ Formula
¢ Compound
Word Definition
DIFFERENTIATE THE 2 COLUMNS:
I II MgCl2 Ca(OH)2
KF KClO3 SO2 NH4OH
N2O5 FeCrO4
GeCl2 NaCH3COO
Al2S3 Ca(NO3)2
CuBr2 NaMnO4
DIFFERENTIATE THE 2 COLUMNS:
I II MgCl2 SO2
Al2S3 N2O5
CuBr2 CO2
NaCl NH4
HOW MANY IONS OF EACH ELEMENT ARE PRESENT IS THE FOLLOWING COMPOUNDS?
1. MgCl2
2. KBr 3. Al2S3
4. CaI2 5. NaCl What is the charge on each of the above atoms? Total charge on a compound is ZERO. These compounds are composed of monatomic ions. Monatomic ions = ions formed from a single type of
atom The above compounds are called binary ionic
compounds. Why?
NAMING BINARY IONIC COMPOUNDS
Rules: ¢ Name the cation with the elements name. ¢ Use the root of the anion and change the ending
to –ide. ¢ Example: NaCl = sodium chloride
NAMING BINARY COMPOUNDS
1. MgCl2
2. KBr 3. Al2S3
4. CaI2 5. NaCl
Common anions: Fluoride Nitride Chloride Oxide Bromide Sulfide Iodide Phosphide
COMPLETE THE PRACTICE ON P. 207 #1-2. 1. Write formulas for the binary ionic compounds formed
between the following elements: a. K and I b. Mg and Cl c. Na and S d. Al and S e. Al and N
2. Name the binary ionic compounds indicated by the following formulas: a. AgCl b. ZnO c. CaBr2 d. SrF2 e. BaO f. CaCl2
ADDITIONAL PRACTICE:
1. Write the formula for the following binary ionic compounds: a. Mg and I b. K and S c. Al and Cl d. Zn and Br e. Cs and S f. Sr and O g. Ca and N
2. Name the following binary ionic compounds: a. BaF2
b. CaO c. AgF d. CdO e. K3N f. NaI g. AlBr3
STOCK SYSTEM OF NOMENCLATURE ¢ Some elements have 2 or more cations. ¢ Example: Fe+2 and Fe+3
¢ Mark these elements on your periodic table: Cu+1 and Cu+2
Cr+2 and Cr+3
Fe+2 and Fe+3
Pb+2 and Pb+4
Sn+2 and Sn+4
V+2 , V+3, and V Ag+1
¢ Roman numerals are placed after the name( never in a formula ) to indicate the charge or oxidation number
¢ Example: copper (I) chloride = CuCl iron (III) bromide = FeBr3
PRACTICE:
1. Write the formula and give the name for the compounds formed between the following ions: a. Cu+2 and Br-
b. Fe+2 and O-2
c. Pb+2 and Cl-
d. Hg+2 and S-2
e. Sn+2 and F-
f. Fe+3 and O-2
2. Give the names for the following compounds: a. CuO c. SnI4
b. CoF3 d. FeS
DAY 1 HOMEWORK: NAME THE FOLLOWING IONIC COMPOUNDS
1. MgCl2
2. KF
3. GeCl2
4. Al2S3
5. CuBr 6. CuBr2
7. FeO 8. Fe2O3
9. MgS 10. CaI2
11. K2S 12. CrCl2
13. Ag2O 14. CaO 15. Ba3P4
16. NaF 17. Na2O 18. BeS 19. MnO 20. BaCl2
21. FeBr2
22. CaCl2
23. AgBr 24. Na3P 25. AlI3
26. CdBr 27. SnO 28. Ba3N2
29. VO 30. NaCl
DAY 1 HOMEWORK: NAME THE FOLLOWING IONIC COMPOUNDS
DAY 1 HOMEWORK: WRITE THE FORMULA FOR THE FOLLOWING.
1. tin (II) fluoride 2. potassium oxide 3. aluminum sulfide 4. silver iodide 5. copper (II) chloride 6. magnesium oxide 7. zinc sulfide 8. lead (IV) nitride 9. barium oxide 10. lithium chloride
11. sodium phosphide 12. vanadium (II) chloride 13. strontium (III) chloride 14. silver fluoride 15. cesium oxide 16. aluminum bromide 17. gold oxide 18. potassium iodide 19. titanium phosphide 20. iron (II) oxide
DAY 1 HOMEWORK: WRITE THE FORMULA FOR THE FOLLOWING.
DAY 2 CHEMISTRY I POWER POINT PRESENTATION
Objectives: ¢ Explain the significance of a chemical formula. ¢ Determine the formula of an ionic compound. ¢ Design a presentation.
CHEMICAL COMPOUNDS POWERPOINT PRESENTATION
¢ This will be 2 TEST GRADES!!!!!!! ¢ 1 grade for content ¢ 1 grade for presentation
CHEMICAL COMPOUNDS POWERPOINT PRESENTATION
¢ Each student will select a metal and a non-metal to form their compound. No two students in a class are allowed to have the same compound.
¢ Take a few minutes to decide, then sign up your two elements beside your name on the list on my desk.
¢ This presentation will count as 2 TEST GRADES!
CHEMICAL COMPOUNDS POWERPOINT PRESENTATION
Items that you must have in your project to receive a grade of 100 on the content grade.
1. Chemical compound a. Chemical formula b. Name of chemical compound c. Common name if applicable d. Interesting facts e. Usages f. Physical description g. State of matter
CHEMICAL COMPOUNDS POWERPOINT PRESENTATION
2. For each element present in compound a. Symbol b. Number of protons, neutrons, and electrons c. Most common charge(s) d. Interesting facts e. Usages f. Most common state of matter g. Physical description
CHEMICAL COMPOUNDS POWERPOINT PRESENTATION
3. PowerPoint slides a. Minimum of 4 slides b. Minimum of 4 pictures c. 15 lines or less per slide d. Logical flow to slides e. Correct grammar and spelling f. Last slide must be work cited
LAST SLIDE
Works cited:
http://www.greensboro-nc.gov/NR/rdonlyres/3DE716E2-060E-43E2-ACC2-D4FDEE5B6825/0/formulas.jpg
http://www.findsounds.com/ISAPI/search.dll www.homewood.k12.al.us/~kreaves/oxidation.JPG
CHEMICAL COMPOUNDS POWERPOINT PRESENTATION
4. Day of presentation a. Paper copy must be turned in with
presentation b. Must be on time ---- NO EXCEPTIONS c. Must be on a flash drive to present to class and must be checked in the library before used on my computer
CHEMICAL COMPOUNDS POWERPOINT PRESENTATION
Items that you must have in your project to receive a grade of 100 on the presentation grade.
These are covered on the Presentation Rubric handout.
DIFFERENTIATE THE 2 COLUMNS:
I II MgCl2 Ca(OH)2
KF KClO3 SO2 NH4OH
N2O5 FeCrO4
GeCl2 NaCH3COO
Al2S3 Ca(NO3)2
CuBr2 NaMnO4
POLYATOMIC IONS 1- 2- 3-
Acetate Carbonate Phosphate
Bromate Chromate Arsenate
Chlorate Dichromate
Chlorite Hydrogen phosphate
cyanide Oxalate
Dihydrogen phosphate
peroxide
Hydrogen carbonate (Bicarbonate)
Sulfate
Hydrogen sulfate Sulfite
Hydroxide
Hypochlorite
Nitrate
Nitrite
Perchlorate
Permanganate
POLYATOMIC IONS
¢ Oxyanions = polyatomic ions that contain oxygen ¢ Sometimes oxyanions are formed by the same 2
elements. ¢ Example: NO3
- and NO2- (NO3
- is the most common)
¢ The most common ion is given the ending –ate. ¢ The ion with one less oxygen is given the ending –
ite. ¢ Sometimes there are more ions. ¢ Example: ClO- ClO2
- ClO3- ClO4
-
¢ The anion with one less oxygen than the –ite ending has the hypo- prefix. The anion with one more oxygen than the –ate ending has the per- prefix.
¢ ClO3- is the most common.
¢ Name the anions above.
POLYATOMIC IONS
¢ Note: There are only 2 cations. ¢ Note: NH4
+
¢ What is the name of this cation? ¢ Do not confuse this with NH3. ¢ Remember an ion has a charge.
WRITE THE FORMULA FOR TIN (IV) SULFATE.
PRACTICE
Give the names for the following compounds: a. Ag2O b. Ca(OH)2
c. KClO3
d. NH4OH e. FeCrO4
f. KClO
PRACTICE:
Write the formulas for the following ionic compounds: a. Sodium iodide b. Calcium chloride c. Potassium sulfide d. Lithium nitrate e. Copper (II) sulfate f. Sodium carbonate g. Calcium nitrate h. Potassium perchlorate
EXTRA PRACTICE
Write the formulas for the following ionic compounds:
a. Copper(II) nitrate b. Potassium iodide c. Sodium hydroxide d. Ammonium acetate e. Calcium carbonate f. Potassium permanganate g. Sodium sulfate h. Iron(III) nitrate
EXTRA PRACTICE
Give the names of the following compounds: a. Ag2S b. NaMnO4
c. Ba(OH)2
d. NH4NO3
e. Fe(ClO)2
f. Ca(NO3)2
g. K2SO3
h. NaCH3COO
DIFFERENTIATE THE 2 COLUMNS:
I II MgCl2 SO2
Al2S3 N2O5
CuBr2 CO2
NaCl NH3
NAMING BINARY MOLECULAR COMPOUNDS
¢ Unlike ionic compounds, molecular compounds are composed of individual covalently bonded units, or molecules!!!!!!
¢ There are 2 nomenclature systems to name binary molecules.
¢ The older system uses prefixes. ¢ The newer system is the Stock system.
NAMING BINARY MOLECULAR COMPOUNDS
Rules for prefix system: 1. Less-electronegative element is given first. It is given a
prefix only if there is more than one atom. 2. Second element is named by combining (a) a prefix
indicating the number of atoms, (b) the root of the second element, and (c) the ending –ide.
3. The o or a at the end of a prefix is usually dropped when the word following the prefix begins with a vowel (example: monoxide or pentoxide).
Unlike ionic formulas, molecular formulas are not reduced to the simplest ratio of atoms in the compound. The actual number of atoms is shown.
Example: benzene C6H6
NAMING BINARY MOLECULAR COMPOUNDS
Number Prefix
1 mono-
2 di-
3 tri-
4 tetra-
5 penta-
6 hexa-
7 hepta-
8 octa-
9 nona-
10 deca-
NAMING BINARY MOLECULAR COMPOUNDS
Formula Prefix-system name
N2O
NO
NO2
N2O3
N2O4
N2O5
NAMING BINARY MOLECULAR COMPOUNDS
Give the name of As2O5. Write the formula for oxygen difluoride.
NAMING BINARY MOLECULAR COMPOUNDS
Name the following binary molecular compounds: a. SO3
b. ICl3
c. PBr5
Name these using the Stock system. Write the formula for the following compounds: a. Carbon tetriodide b. Phosphorus trichloride c. Dinitrogen trioxide How would these be named using the Stock
system?
NAMING BINARY MOLECULAR COMPOUNDS
Name the following binary molecular compounds: a. PF5
b. XeF4
c. CCl4
Write formulas for the following compounds: a. Carbon dioxide b. Dinitrogen pentoxide c. Sulfur hexafluoride
SECTION REVIEW P. 215
2. Write the formulas for the compounds formed between the following:
a. Aluminum and bromine b. Sodium and oxygen c. Magnesium and iodine d. Pb2
+ and O2-
e. Sn2+ and I-
f. Fe3+ and S2
-
g. Cu2+ and NO3
-
h. NH4+ and SO4
2-
SECTION REVIEW
3. Name the following compounds using the Stock system:
a. NaI b. MgS c. CaO d. K2S e. CuBr f. FeCl2
SECTION REVIEW
4. Write formulas for each of the following compounds:
a. Barium sulfide b. Sodium hydroxide c. Lead(II) nitrate d. Potassoum permanganate e. Iron(II) sulfate f. Diphosphorus trioxide g. Disulfur dichloride h. Carbon diselenide
DAY 2 HOMEWORK: NAMING NON-BINARY COMPOUNDS 1. NaNO3
2. Ca(OH)2
3. K2CO3
4. NH4Cl 5. MgSO4
6. AlPO4
7. (NH4)2SO4
8. Na3PO4
9. CuSO4
10. NH4OH
11. Li2SO3
12. Mg(NO3)2
13. Al(OH)3
14. (NH4)3PO4
15. KOH 16. Ca(NO3)2
17. K2SO4
18. Pb(OH)2
19. Na2O2
20. CuCO3
Day 2 Homework: formulas with polyatomic ions – complete the table
OH -1 NO3-1 CO3
-2 SO4-2 PO4
-3
H HOH HNO3 H2CO3
Na
Mg
NH4+1
Ca
K
Al
Pb+4
DAY 2 HOMEWORK: NAMING BINARY COVALENT COMPOUNDS
1. CO 2. CO2
3. SO2
4. NO2
5. N2O 6. SO3
7. CCl4
8. NO 9. N2O5
10. P2O5
11. N2O4
12. CS2
13. OF2
14. PCl3
15. PBr5
Day 3 Section 7.3 Using Chemical Formulas
Objectives: ¢ Calculate the formula mass or molar mass of any
given compound. ¢ Use molar mass to convert between mass in
grams and amount in moles of a chemical compound.
¢ Calculate the number of molecules, formula units, or ions in a given molar amount of a chemical compound.
¢ Calculate the percentage composition of a given chemical compound.
FORMULA MASSES
¢ Formula mass = sum of the average masses of all atoms represented in its formula
¢ Formula mass = molecular mass ¢ Atomic masses are rounded to 2 decimal places
for all calculations in this book. ¢ Formula mass and molar mass are numerically
equal, but different in units. ¢ Formula mass = amu ¢ Molar mass = g/mol
FIND THE FORMULA MASS FOR POTASSIUM CHLORATE.
What is the formula?
FIND THE MOLAR MASS OF EACH BELOW:
a. Hydrogen sulfate b. Calcium nitrate c. Phosphate ion d. Magnesium chloride
TEST NEXT CLASS ON NOMENCLATURE
DAY 3 HOMEWORK: NAME THE FOLLOWING
1. BaCl2
2. N2O 3. Ag2O 4. CuBr 5. CuBr2
6. NH4OH 7. Fe2O3
8. PBr5 9. Al2O3
10. Al2(SO4)3
11. K2S 12. CrCl2
13. CrCl3
14. NO3 15. Ba3P2
16. Hg2I2
17. Na2O 18. CO 19. Pb(OH)3
20. Mn2O3
DAY 3 HOMEWORK: NAME EACH AND CALCULATE THE MOLAR MASS
1. Na2CO3
2. NaOH 3. MgBr2
4. KCl 5. FeCl2
6. FeCl3
7. Zn(OH)2
8. Be2SO4
9. CrF2
10. Al2S3
Name Molar Mass
DAY 3 HOMEWORK: NAME EACH AND CALCULATE THE MOLAR MASS
11. PbO 12. Li3PO4
13. TiI4
14. Co3N2
15. Mg3P2
16. Ga(NO2)3
17. Ag2SO3
18. NH4OH 19. Al(CN)3 20. Be(CH3COO)2
Name Molar Mass
Day 3 Homework: write the formula and calculate the molar mass
31. Iron (III) oxide 32. Gallium nitride 33. Iron (II) bromide 34. Vanadium (V)
phosphate 35. Calcium oxide 36. Magnesium acetate 37. Aluminum sulfate 38. Copper (I) carbonate 39. Barium oxide 40. Ammonium sulfite
Formula Molar Mass
DAY 3 STUDY FOR TEST TEST NEXT CLASS ON NOMENCLATURE
DAY 5 WHAT IS THE MASS IN GRAMS OF 2.50 MOL OF OXYGEN GAS?
Oxygen gas = O2
WHAT IS THE MASS IN GRAMS OF 6.25 MOL OF COPPER (II) NITRATE?
HOW MANY MOLES OF COMPOUND ARE THERE IN THE FOLLOWING:
a. 6.60 g (NH4)2SO4
b. 4.5 g Ca(OH)2
HOW MANY MOLECULES ARE THERE IN THE FOLLOWING:
a. 25.0 g H2SO4
b. 125 g sugar, C12H22O11
PERCENTAGE COMPOSITION
Find the percentage composition of Cu and S in copper (I) sulfide.
Do your results equal 100%?
PRACTICE
Find the % compositions of the following: a. PbCl2
b. Ba(NO3)2
SECTION REVIEW P. 228
1. Determine both the formula mass and the molar mass of ammonium carbonate.
2. How many moles of atoms of each element are there in one mole of ammonium carbonate?
3. What is the mass in grams of 3.25 mol iron(III) sulfate?
4. How many moles of molecules are there in 250 g of hydrogen nitrate?
5. How many molecules of aspirin, C9H8O4 are there in a 100.0 mg tablet of aspirin?
6. Calculate the % composition of each element found in ammonium carbonate.
DETERMINE BOTH THE FORMULA MASS AND THE MOLAR MASS OF AMMONIUM CARBONATE.
HOW MANY MOLES OF ATOMS OF EACH ELEMENT ARE THERE IN ONE MOLE OF AMMONIUM CARBONATE?
WHAT IS THE MASS IN GRAMS OF 3.25 MOL IRON(III) SULFATE?
HOW MANY MOLES OF MOLECULES ARE THERE IN 250 G OF HYDROGEN NITRATE?
HOW MANY MOLECULES OF ASPIRIN, C9H8O4 ARE THERE IN A 100.0 MG TABLET OF ASPIRIN?
CALCULATE THE % COMPOSITION OF EACH ELEMENT FOUND IN AMMONIUM CARBONATE.
DAY 5 HOMEWORK: P. 236 #32-34
DAY 6 SECTION 7.4 DETERMINING CHEMICAL FORMULAS
Objectives: ¢ Define empirical formula, and explain how the
term applies to ionic and molecular compounds. ¢ Determine an empirical formula from either a
percentage or a mass composition. ¢ Explain the relationship between the empirical
formula and the molecular formula of a given compound.
¢ Determine a molecular formula from an empirical formula.
SECTION 7.4 DETERMINING CHEMICAL FORMULAS
¢ Empirical formulas = formula showing the smallest whole-number mole ratio of atoms in the compound
¢ Problem: Find the empirical formula of a compound that contains 32.38% Na, 22.65% S, and 44.99% O. First change % to grams then calculate moles of each. Divide each by the smallest of these numbers. Round to the nearest whole number.
PROBLEM
Analysis of a 10.150 g sample of a compound known to contain only P and O indicates a P content of 4.433 g. What is the empirical formula of this compound?
PROBLEM
Using the information form the last problem, determine the molecular formula of this compound if the molar mass is 283.89 g/mol.
SECTION REVIEW P. 233
1. A compound is found to contain 36.48% Na, 25.41% S, and 38.11% O. Find its empirical formula.
2. Find the empirical formula of a compound that contains 53.70% Fe and 46.30% S.
3. Analysis of a compound indicates that it contains 1.04 g K, 0.70 g Cr, 0.86 g O. Find its empirical formula.
4. If 4.04 g of N combine with 11.46 g of O to produce a compound with a formula mass of 108.0 amu, what is the molecular formula of this compound?
5. The molar mass of a compound is 92 g/mol. Analysis of a sample of the compound indicates that it contains 0.606 g N and 1.390 g O. Find its molecular formula.
A COMPOUND IS FOUND TO CONTAIN 36.48% NA, 25.41% S, AND 38.11% O. FIND ITS EMPIRICAL FORMULA.
FIND THE EMPIRICAL FORMULA OF A COMPOUND THAT CONTAINS 53.70% FE AND 46.30% S.
ANALYSIS OF A COMPOUND INDICATES THAT IT CONTAINS 1.04 G K, 0.70 G CR, 0.86 G O. FIND ITS EMPIRICAL FORMULA.
IF 4.04 G OF N COMBINE WITH 11.46 G OF O TO PRODUCE A COMPOUND WITH A FORMULA MASS OF 108.0 AMU, WHAT IS THE MOLECULAR FORMULA OF THIS COMPOUND?
THE MOLAR MASS OF A COMPOUND IS 92 G/MOL. ANALYSIS OF A SAMPLE OF THE COMPOUND INDICATES THAT IT CONTAINS 0.606 G N AND 1.390 G O. FIND ITS MOLECULAR FORMULA.
CLASS WORK: P. 236 #26, 30, 36, 37, 47, 50