Chemistry Unit 6: Chemical Formulas and Compounds Textbook Connection: Chapter 7 Learning Targets Learning Target Assessment Name ___________________________________ Block _________ Score: 5 4 3 Test #1 2 1 Test #2 I can correctly write chemical formulas and names for binary ionic, covalent and acid compounds. I can correctly write chemical formulas and names for compounds that contain polyatomic ions. I can determine oxidation numbers for ternary compounds. I can calculate percentage composition. I can calculate empirical formula and molecular formula. Please note – Learning Target Checks (LTCs) cannot be retaken. Test #1 is worth 25 points and Test #2 is worth 15 points. Test #3 will be worth 10 points and with completion of this learning packet the opportunity to replace Test #1 score with the sum of Test #2 and Test #3 is available. You are strongly encouraged to monitor your level of understanding for the learning targets using the table above. *Modern Chemistry – Sarquis.Sarquis; Houghton, Mifflin, Harcourt (2017) Date My homework Date My homework LT 1: I can correctly write chemical formulas for binary ionic, covalent and acid compounds. The Language of Chemistry Review 1. What do subscripts indicate? 3. How many atoms of each element are found in the following? A. CH4 C: H: B. SO2 S: O: C. O2 O: D. P4O10 P: O: E. Pb(NO3)2 Pb: N: O: 4. What is a cation? 5. What is an anion? 6. What group of elements typically form +1 cations? Why? 7. What group of elements typically form +2 cations? Why? 8. What group of elements typically form -­‐‑1 anions? Why? 9. What group of elements typically form -­‐‑2 anions? Why? 10. What is a monatomic ion? 11. What is a polyatomic ion? 12. When writing chemical formulas for ionic compounds, the overall charge of the compound must equal ____________!! Naming Ionic Compounds Steps to naming or determining formulas of binary ionic compounds: Formula: A) Determine the charge on each element using its placement on the periodic table.
B) Balance the charges by adding more of each element as necessary.
C) Hint: The charge number of the cation (the positive ion) is the subscript of the anion (the negative ion) and vice versa.
Name: A) Write the name of the cation first.
B) Follow with the name of anion ending with –ide.
1) Binary compounds are compounds made of ______________________ elements. 2) For the following binary ionic compounds, write the name of the compound: NaI _____________________________ MgO _____________________________ Al2O3 _____________________________ KBr _____________________________ MgI2 Li2O _____________________________ _____________________________ SrF2 _____________________________ Rb2O _____________________________ 3) For the following binary ionic compounds, write the formula: strontium chloride _________________ sodium selenide _________________ radium sulfide _________________ beryllium nitride _________________ potassium sulfide _________________ calcium oxide _________________ Steps to naming binary ionic compounds or determining formulas with transition metals: Formula: A) Determine the charge of the anion.
B) Use the charge of the anion and the charge of the cation (the roman numeral) to determine how many of each element
will be necessary to balance.
C) Hint: The charge number of the cation (the positive ion) is the subscript of the anion (the negative ion) and vice versa.
Name: A) Determine the roman numeral by looking at the subscripts.
B) The anion subscript will be the charge of the transition metal cation as before.
C) Write the name with the transition metal first, then the roman numeral in parentheses, followed by the anion ending with
–ide.
4) For the following ionic compounds that include transition metals, write the formula: tin(IV) iodide _________________ iron(III) oxide _________________ nickel(I) phosphide cobalt(II) bromide _________________ iron(III) sulfide _________________ _________________ cobalt(III) oxide _________________ 5) For the following formulas that include transition metals, write the compound name: Fe2O3 _____________________________ SnI2 _____________________________ _____________________________ PbO _____________________________ CoF3 CuO _____________________________ PbCl2 _____________________________ Steps for determining which method to use: A) B) C) D) For naming, determine if the metal is a transition metal.
If it is a transition, metal, use roman numerals and parentheses for the name.
If it is not a transition metal, you do not need roman numerals.
For writing formula, use the Roman numeral for charge on transition metal.
6) Write the correct chemical formula for each of the following compounds. potassium bromide tin(IV) chloride magnesium selenide aluminum oxide sodium phosphide scandium(III) sulfide 7) Give the correct names for each of the following compounds listed below. KF SnI4 SiF4 AlBr3 FeCl3 ZnO Naming Molecular Compounds and Acids Steps for naming molecular compounds and formulas using prefix method: Formula: A) Use the prefixes to determine the subscripts.
Name: A) B) C) D) Use prefixes to indicate the number of each element are necessary.
The less electronegative element is listed first and only gets a prefix if it is greater than one.
The second element always gets a prefix and the ending of the element name is changed to –ide.
The ending of the prefix is typically dropped if the element starts with a vowel.
8) For the following molecular compounds, write the molecular formula: carbon mononitride sulfur tribromide _____________
sulfur trioxide _____________
______________ tricarbon pentnitride _____________
______________ dihydrogen monoxide _____________ phosphorus triflouride nitrogen dioxide ______________ dinitrogen hexoxide carbon tetrachloride ______________ sulfur dichloride 9) For the following molecular formulas, write the compound name: SiO2 CO2 _____________ _____________ ________________________________ As2O5 ________________________________ ________________________________ AsI3 ________________________________ ________________________________ PCl5 ________________________________ ________________________________ CF4 ________________________________ SeF6 N2O5 Steps for naming acids: Formula: A) Determine if the acid is a binary acid (contains 2 different elements) or oxyacid ion (a compound of hydrogen,
oxygen and a third element/contains a polyatomic ion) using the name.
B) Use the charges of the ions (polyatomic or monatomic) to determine the number of
Hydrogen atoms.
Name: A) Binary acid (2 elements)
• Start with the prefix –hydro
• Write the root of the second element
• End the name with –ic and add the word acid
B) Oxyacid (3 elements)
• Do NOT start with –hydro
• Write the name of the polyatomic ion and drop the ending.
• Replace ending with –ic if the polyatomic ion ends with –ate
• Replace ending with –ous if the polyatomic ion ends with –ite
• Add the word acid
10) Name the following binary acids: HF H2S _________________________________ HCl _________________________________ ________________________________ HI _________________________________ _________________________________ H2SO4 _________________________________ _________________________________ H3PO4 _________________________________ 13) Name the following oxyacids: HNO3 H2CO3 HNO2 _________________________________ 11) Write the formulas for the following acid names: sulfurous acid ________________________________ phosphoric acid ________________________________ bromic acid perchloric acid ________________________________ hydrobromic acid ________________________________ ________________________________ hydrochloric acid ________________________________ LT 2: I can correctly write chemical formulas for naming compounds that contain polyatomic ions. Steps for naming/determining chemical formulas with polyatomic ion compounds: Formula: A) B) C) D) Find the polyatomic ion on the chart and note the charge.
Use the charge together with the charge of the other ion to determine the subscripts (number of atoms) of each element.
Just as before, the charge of one will be the subscript of the other.
Use parentheses around the polyatomic ion if more than one is needed to balance.
Name: A) Find the polyatomic ion of the chart.
B) Write the name of the cation first followed by the anion.
C) If the anion is the polyatomic ion (as it typically is), write the name of the ion, do not change ending to –ide.
12) Write the chemical formulas for the following names: sodium carbonate iron(III) acetate gold(III) sulfate tin(II) permanganate ammonium phosphate calcium nitrate barium phosphate copper(II) hydroxide 13) Write the names for the following chemical formulas: Cr2(SO3)3 CuCO3 NH4Cl NaHCO3 FeC2O4 Pb(Cr2O7)2 Al(MnO4)3 Ba(OH)2 Mixed Review 14) Write the names for the following chemical formulas: 1. Pb(SO3)2 ___________________________________ 2. SrF2 ________________________________________ 3. (NH4)2CO3 __________________________________ 4. H3PO4 ______________________________________ 5. PCl5 ________________________________________ 6. N3H2______________________________________ 7. CuO _______________________________________ 8. Al2(CrO4)3 ________________________________ 9. HBr _________________________________________ 10. CoS _______________________________________ 15) Write the chemical formulas for the following names: 1. Hydriodic Acid _______________________________ 6. Dichlorine Heptoxide ______________________ 2. Diphosphorus Tetraiodide __________________ 7. Tin (IV) Chloride _________________________ 3. Potassium Selenide __________________________ 8. Aluminum Oxalate _________________________ 4. Silver Hydroxide _____________________________ 9. Nickel (II) Phosphate ______________________ 5. Chromic acid _________________________________ 10. Ammonium Sulfide _______________________ LT 3: I can determine oxidation numbers for ternary compounds. Oxidation Numbers Steps for determining Oxidation Numbers: A) These numbers are used to indicate the general distribution of electrons among bonded atoms in a compound.
B) Each atom is assigned a number.
C) The rules are listed on page 232 and simplified below:
1. All elements not in compound have an oxidation number of 0 (H2 N2 O2 F2 Cl2 Br2 I2, P4, S8) 2. In binary compounds (2 elements), the first element is assigned a positive number equal to its cation. The second is assigned a negative number equal to its charge as an anion. 3. Fluorine has a charge of –1 in all compounds; it is the most electronegative element. 4. Oxygen is –2, except for peroxide (H2O2), where it is a –1, or when it is at the beginning (OF2 for example), where it is +2 5. Hydrogen is +1 if it is listed first. 6. Any element in group 1 is +1 7. Any element in group 2 is +2 8. The sum of the oxidation numbers in a compound is 0 9. Rules apply to both covalent and ionic compounds. 10. Monatomic ions have oxidation numbers equal to their charge; the sum of oxidation numbers for a polyatomic ion is equal to the charge of the ion 11. Use process of elimination to determine charge on unknown. D) Examples:
CF4 H2O C = +4, F = -­‐‑1 H=+1, O=-­‐‑2 P4O10 H2SO4 P = +5, O= -­‐‑2 H=+1, S=+6,O=-­‐‑2 16) For the following compounds, assign oxidation numbers to the atoms of each element. PI3 ___________________________ CI4 ___________________________ HF ___________________________ HCl ___________________________ ___________________________ SO3 ___________________________ ___________________________ IO3 ___________________________ __________________________ H2CO3 __________________________ SO42-­‐‑ __________________________ CS2 As2S3 NO2-­‐‑ Na2O2 __________________________ LT4: I can calculate percentage composition. Percent Composition What is percent composition? How do you calculate percent composition? In-­‐‑Class Examples: Percent Composition Determine the percent composition in the following compounds: 17) PbBr4 18) Ba(OH)2 Independent Practice: Percent Composition Determine the percent composition in the following compounds: 19) NaOH 20) CCl2F2 21) (NH4)3PO4 22) Pb(NO3)2 LT 5: I can calculate empirical formula and molecular formula. 23) What is the definition of empirical formula? How do you calculate empirical formulas? 24) What is the molecular formula? How do you calculate molecular formula? 25) How does the molecular formula differ from the empirical formula? In Class Examples: Empirical and Molecular Formulas 26) The percent composition of a compound was found to 63.5 % silver, 8.2 % nitrogen, and 28.3 % oxygen. Determine this compound’s empirical formula. 27) A 170.00 g sample of a compound contains 29.84 g sodium, 67.49 g chromium and 72.67 g oxygen. What is the empirical formula? 28) 200.00 grams of an organic compound is known to contain 83.884 grams of carbon, 10.486 grams of hydrogen, 18.640 grams of oxygen and the rest is nitrogen. What is the empirical formula of the compound? 29) A compound of boron and hydrogen has a percent composition of 78.14 % boron and 21.86 % hydrogen. If the molar mass is 27.6, what is the empirical and molecular formula? 30) A compound with the formula C2H5O is found to have a molar mass of 90 g. What is the molecular formula of the compound? Independent Practice: Empirical and Molecular Formulas 31) Determine the empirical formula of methane given that 6.0 g of methane can be decomposed into 4.5 g of carbon and 1.5 g of hydrogen. 32) If a molecule is 18.7% lithium, 16.3% carbon, and 65.0% oxygen, what is the empirical formula? 33) Determine the empirical formula of the compound made when 8.65 g of iron combines with 3.72 g of oxygen. 34) What is the empirical formula of a compound that contains 32.8% chromium and 67.2% chlorine? 35) What is the empirical formula for a compound that contains 0.0268 g of iron, 0.0154 g of sulfur and 0.023 g of oxygen? 36) Many compounds have the empirical formula of CH2O. What is the molecular formula for the compound with a molar mass of 60? 37) Caffeine has the following percent composition: carbon 49.48%, hydrogen 5.19%, oxygen 16.48% and nitrogen 28.85%. Its molecular weight is 194.19 g/mol. What is its molecular formula? 38) What is the molecular formula of a compound with an empirical formula of C2OH4 and a molar mass of 88 grams per mole? 39) The amino acid serine has an approximate molar mass of 100 g/mole. If the percent composition is as follows, what is the empirical and molecular formula of serine? C = 34.95 % H= 6.844 % O = 46.56 % N= 13.59 % 40) What is the empirical formula for the following? C6H12O6 _______________________ C8H6O4 _______________________ 41) If the empirical formula is N2H2, what are 3 possible molecular formulas? 42) If the molecular formula is Na2C2O4, what is the empirical formula? 43) If the empirical formula is C2H5, what is one possible molecular formula?