STUDY GUIDE – Chemical Bonding & Formulas Learning Objectives for Unit: () will indicate more specifically what you need to show! Demonstrate how substances can react chemically with other substances to form new substances, known as compounds, and that in such re-combinations the properties of the new substances may be very different from those of the old. (Must be clear on vocabulary, what is an atom? Compound? Do they have the same properties? Why/why not?) Explain interactions between atoms that hold them together in molecules or between oppositely charged ions are called chemical bonds. (Covalent and Ionic Bonding – how does it happen?) Explain how the configuration of atoms determine the molecular combinations. (Why do atoms form different types of bonds? What does this have to do with atonic structure?) Distinguish between ionic, covalent, and metallic bonds. (Similarities & Differences – at least 3) Explain why most atoms form chemical bonds. (must use appropriate vocabulary) Describe the formation of ions by electron loss or gain (SHOW how ions form, why do ions form? Must show charges that result from loss or gain.) Describe the formation of ionic bonds between metals and non-metals (Show using Lewis structures, must show transfer of electrons AND show charges that result) Define the terms molecule, molecular formula and empirical formula State the octet rule Describe how bonds are created by sharing electrons. Draw Lewis structures to showing covalent bonding involving single and multiple bonds. Describe the electron-sea model of metallic bonding Describe the general physical and chemical properties of metals (explain these properties as it relates to metallic bonding) Use the symbols of the elements and write the formula of simple compounds. (ionic & covalent) Deduce the formula of a simple compound from the relative number of atoms present (ionic formulas – REMEMBER: Compounds DON’T have a CHARGE) Name ionic compounds given a formula (ionic naming) List the formulas for the following polyatomic ions; ammonium, hydrogen carbonate (bicarbonate), hydrogen sulfate, hydroxide, nitrate, carbonate, sulfate, phosphate Using prefixes, name a binary molecular compound from its formula (covalent naming) Write the formula of a binary molecular compound given its name. (covalent formulas) Calculate the number of molecules, formula units, or ions in a given molar amount of a chemical compound (see mole calculation worksheet on back of empirical formula worksheet) Calculate the percent composition of a given chemical compound. Determine the empirical and molecular formulas from given lab data (Block B only empirical) Use dimensional analysis to perform calculations Determine the number of significant figures in measurements. Perform mathematical calculations involving significant figures. Practice Questions 1. Draw the Lewis structures for the following atoms: a. Rubidium b. Argon c. Silicon d. Iodine e. Sulfur f. Radium g. Aluminum h. Arsenic 2. Determine what type of bond will form between the following elements (use electronegativity table on p. 151 of your textbook) – NOTE: if covalent you must specify which type of covalent! a. b. c. d. Lithium and chlorine Beryllium and Phosphorous Magnesium and aluminum Carbon and Nitrogen e. f. g. h. Tin and Oxygen Gallium and nitrogen Phosphorous and sulfur Copper and zinc 3. Use Lewis structures to show how the following atoms bond (ionic bonds) - see steps below a. Potassium and Oxygen b. Cesium and nitrogen c. Boron and Fluorine i. ii. iii. iv. 4. Show the Lewis structures and transfer of electrons Show the number and charges of each ion that is formed Write the correct chemical formula Write the correct chemical name Use Lewis structures to show how the following covalent compounds form, then name the compound - see hints below a. SO2 d. O3 b. P2 e. PH2Cl c. C2H2 i. Must show SHARING of electrons ii. May involve multiple bonds iii. Follow the steps shown in class (look at your notes for the steps) 5. Name the following compounds (NOTE: You first must determine if they are ionic or covalent compounds) a. b. c. d. e. SiO2 LiN3 Fe2O3 CSe2 S4N2 f. g. h. i. j. (NH4)3PO4 MnBr2 SF6 FePO4 N2O5 k. l. m. n. o. Cr2S3 Cu2CO3 MgS C2H4 Pb(OH)2 6. Write the chemical formulas for the following compounds (NOTE: You first must determine if they are ionic or covalent compounds) a. b. c. d. e. f. Dichlorine monoxide Ammonium carbonate Radium nitride Tetraphosphorous heptoxide Calcium hydrogen carbonate Arsenic pentachloride g. h. i. j. k. l. Copper (II) chloride Hydrogen sulfide Aluminum nitrate Iodine tribromide Iron (III) hydroxide Titanium (IV) oxide 7. Use dimensional analysis to solve the following problems. Follow significant figure rules! a. One type of antibiotic, penicillin F, has the formula C14H20N2SO4. How many moles of penicillin are there in a 250 mg (0.25 g) sample? How many molecules of penicillin are there in this dose? b. How many iron ions are there in 5.33 moles of iron (III) chloride? c. How many formula units are there in 2.45 grams potassium chloride? d. How many total ions are found in 12.6 moles of copper (II) sulfate? 8. Determine the percent composition of the following compounds: a. H3PO4 b. Mg(NO3)2 c. Na2CO3 d. Al2(SO4)3 9. Determine the empirical formula for the following compounds containing: a. 42.9% C, 57.1% O b. 12.12% C, 16.16% O, 71.72% Cl c. 0.276 g Na, 0.385 g S, 0.288 g O 10. A 2.65 g sample of a salmon-colored powder contains 0.70 g of chromium, 0.65 g of sulfur, and 1.30 g of oxygen. What is the empirical formula of the compound? 11. Determine the empirical and molecular formulas for the following (Blocks G and H only) a. A compound with the empirical formula C4H4O, has a molar mass of 136 g/mol. What is the molecular formula of this compound? b. A component of protein called serine has an approximate molar mass of 100. g/mole. If the percent composition is 34.95% C, 6.844% H, 46.56% O, and 13.59% N, determine the empirical and molecular formulas for serine. c. Histamine is a substance that is released by cells in response to injury, infection, stings, and materials that cause allergic responses, such as pollen. Histamine causes dilation of blood vessels and swelling due to accumulation of fluid in the tissues. People sometimes take antihistamine drugs to counteract the effects of histamine. A sample of histamine having a mass of 385 mg is composed of 208 mg of carbon, 31 mg of hydrogen, and 146 mg of nitrogen. (Note: mass is given in mg and must be converted to grams first 1g = 1000 mg.) The molar mass of histamine is 111 g/mol. What is the empirical and molecular formula for histamine?