Chapter 3 Review Questions PDF

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Chapter 3 Review Questions...

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1. How do the properties of compounds compare to the properties of the elements from which the compounds are composed? ➔ The properties of compounds and elements are drastically different. The reason for this is that when two elements combine, an entirely new substance forms. 2. What is a chemical bond? Explain the difference between an ionic bond and a covalent bond. 3. Explain the different ways to represent compounds. Why are there so many? ➔ A chemical bond is the force that holds atoms together in a chemical compound. An ionic bond is a bond formed between a metal and a nonmetal. A covalent bond is a bond formed between two nonmetals. An ionic bond shares its electrons while covalent bonds share them. 4. Define and provide an example for each of the following: atomic element, molecular element, ionic compound, molecular compound. ➔ An example of an atomic element is Neon (Ne). An example of a molecular element is oxygen gas (O2). An example of an ionic compound is sodium chloride (NaCl). An example of a molecular compound is water (H2O). 5. Explain how to write a formula for an ionic compound given the names of the metal and nonmetal (or polyatomic ion) in the compound. ➔ The first step is to write the symbol for the metal cation and its charge followed by the symbol for the nonmetal and its charge. The next step is to balance the overall charge. The final step is to check the sums of the cations and anions. 6. Explain how to name binary ionic compounds. How do you name an ionic compound if it contains a polyatomic ion? ➔ Binary ionic compounds are named using the name of the metal and the base name of the nonmetal + -ide. Ionic compounds that have a polyatomic anion are named using the name of the metal and the name of the polyatomic anion 7. Why do the names of some ionic compounds include the charge of the metal ion while others do not? ➔ Ionic compounds that can form more than one cation must include the charge of the cation in the name. Metals that can form only one cation do not need the charge specified. 8. Explain how to name molecular inorganic compounds. ➔ The name molecular inorganic compounds, you need to list the name of the first element with a prefix to indicate the number of atoms in the compound followed by the base name of the second element with a prefix followed by adding -ide at the end. 9. How many atoms are specified by each of these prefixes: mono-, di-, tri-, tetra- , penta- hexa-? ➔ Mono- has 1 atom. Di- has two atoms. Tri- has three atoms. Tetra- has four atoms. Penta- has five atoms. Hexa- has six atoms. 10.Explain how to name binary acids and oxyacids. ➔ To name binary acids, the first step is to write the prefix hydro- followed by the base name of the nonmetal. The next step is to add -ic to the end. The final step is to write acid at the end. To name oxyacids, the first step is to see If the oxyanion ends in -ate. If it does, write the base name of the oxyanion and add the suffix -ic. If the oxyanion ends in -ite, then write the base name of the oxyanion and add the suffix -ous. The final step is to add the word acid to the end. 11.What is the formula mass for a compound? Why is it useful? ➔ Formula mass if the average mass of the molecule of a compound. It is useful because it allows the conversion between the mass of molecules and the number of molecules. 12.What is mass percent composition? Why is it useful? ➔ Mass percent composition is an element’s percentage of the total mass of a compound containing the element. It is helpful because it indicates the relative quantities of each element in a compound. 13.What kinds of conversion factors are inherent in chemical formulas? Provide an example. ➔ Chemical formulas contain inherent relationships between atoms and molecules. Example: formula CCl2F2 tells us that one mole of CCl2F2 contains one mole of C atoms, two moles of CL atoms, and two moles of F atoms. 14.What kind of chemical formula can be obtained from experimental data showing the relative masses of the elements in a compound? ➔ Experimental data showing relative masses of elements in compound can be used to obtain an empirical formula 15.How can a molecular formula be obtained from an empirical formula? What additional information is required? ➔ A molecular formula is a whole-number multiple of an empirical formula. To find the molecular formula, the molar mass of the compound must be known. Molecular mass divided by empirical molar mass gives the whole-number multiple used to convert the empirical formula to the molecular formula 16.What is combustion analysis? What is it used for? ➔ The combustion analysis is used to obtain the empirical formulas of the unknown compound that contains carbon and hydrogen. 17.Which elements are normally present in organic compounds?

➔ Organic compounds are composed of carbon, hydrogen, and a few other elements. 18.What is the difference between an empirical formula and a molecular formula? ➔ The empirical formula gives you a basic idea about the elements involved in the formation of compounds and in which ratio. The molecular formula gives the actual relationship between different atoms within the compound. ...