Writing Chemical Formulas

EXAMPLE 5.2 Writing Chemical Formulas Write a chemical formula for each compound. ... 

Qrthoclase feldspar has the chemical formula KAlSi308. What other cations could replace those in this chemical formula Write the resulting formula for two such minerals. 

Questions that test your knowledge of the specialized vocabulary that chemists use (e.g., write the names of formulas, write the chemical equation for a reaction that is described). 

C.3 The compound xanthophyll is a yellow compound found in bird feathers and flowers. Xanthophyll contains atoms of carbon, hydrogen, and oxygen in the ratio 20 28 1. Its molecules each have six oxygen atoms. Write the chemical formula of xanthophyll. 

C.5 In the following ball-and-stick molecular structures, black indicates carbon, red oxygen, light gray hydrogen, blue nitrogen, and green chlorine. Write the chemical formula of each structure. 

C.6 Write the chemical formula of each ball-and-stick structure. See Exercise C.5 for the color code. 

D.19 You come across some old bottles in a storeroom that are labeled (a) cobaltic oxide monohvdrate, (b) cobaltous hydroxide. Using Appendix 3C as a guide, write their modern names and chemical formulas. 

An equation must never be balanced by changing the subscripts in the chemical formulas. That change would imply that different substances were taking part in the reaction. For example, changing H20 to H202 in the skeletal equation and writing... 

Sei f-Test 10.6A Write the chemical formula for the conjugate acid of the base pyridine, C4H4N, and calculate its pK,. 

Write the chemical formula ol the compound represented by each of the following line structures ... 

Bearing in mind that the relative sizes of the ions permit isomorphous replacement of OH by F but not by Cl, we write with considerable confidence the formula (Si, Al, Fe, P)18O20(OH, F)laCl, which agrees well with analyses 1, 2, and 3. Inasmuch as aluminium (as well as phosphorus) may replace silicon with coordination number 4, it is evident that there are at least five silicon atoms in the unit, corresponding to the chemical formula... 

C02-0065. Write the chemical formula for the species resulting from each of the following processes (a) a chloride anion loses an electron (b) a sodium atom loses an electron and (c) an oxygen atom gains two electrons. 

C02-0069. Write the chemical formulas of all ionic compounds that can form between the elements listed in Problem 2.41. 

A chemical compound is a substance that contains a combination of atoms of different elements. Because a compound contains more than one element, there is more than one way to write its formula. For example, hydrogen chloride is a diatomic molecule with one atom each of hydrogen and chlorine. Its chemical formula might be written as HCl or CIH. To avoid possible confusion, chemists have standardized the writing of chemical formulas. 

Write the correct chemical formulas for the molecules containing sulfur whose molecular pictures follow ... 

Quite often, molecules have the same chemical formula but differ in their structures. For example, two compounds have the chemical formula C2 Hg O (Figure 3-2b and c). Dimethyl ether has a C—O—C linkage, while ethanol contains C—O—H. To distinguish between these two different substances, chemists write the formula of dimethyl ether as CH3 OCH3 and the formula of ethanol as CH3 CH2 OH. The first formula indicates that the molecule has two CH3 units linked to an oxygen atom. The second formula tells us that there is a C2 H5 unit attached to an OH group. Molecules that have the same molecular formula but different arrangements of atoms are called isomers. 

These are the correct structural formulas. Now it is a simple matter to count the number of atoms of each element and write the chemical formulas of the compounds C2 H4 CI2, C4 Hg Og, and C3 H4 O. ... 

C03-0004. Write the chemical formula for each of the following substances (a) stearic acid, whose molecules contain 36 hydrogen atoms, 18 carbon atoms, and 2 oxygen atoms (b) silicon tetrachloride, whose molecules contain one silicon atom and four chlorine atoms and (c) Freon-113, whose molecules contain three atoms each of fluorine and chlorine and two atoms of carbon. 

C03-0008. Write chemical formulas for the following compounds chlorine monofluoride, xenon trioxide, hydrogen bromide, silicon tetrachloride, sulfur dioxide, and hydrogen peroxide. 

There are many different polyatomic anions, including several that are abundant in nature. Each is a stable chemical species that maintains its stmcture in the solid state and in aqueous solution. Polyatomic anions are treated as distinct units when writing chemical formulas, naming compounds, or drawing molecular pictures. The names, formulas, and charges of the more common polyatomic anions are listed in Table 3-4. You should memorize the common polyatomic ions because they appear regularly throughout this textbook. 

C03-0055. Write chemical formulas and names for the compounds whose space-filling models follow ... 

C03-0059. Write chemical formulas for these compounds (a) methane (b) hydrogen iodide (c) calcium... 

C03-0067. Write chemical formulas for these compounds (a) sodium sulfate (b) potassium sulfide (c) potassium dihydrogen phosphate (d) cobalt(II) fluoride tetrahydrate (e) lead(IV) oxide (Q sodium hydrogen carbonate and (g) lithium perbromate. 

C03-0068. Write chemical formulas for these compounds (a) potassium chlorate (b) ammonium hydrogen carbonate (c) iron(II) phosphate (d) copper(II) nitrate hexahydrate (e) aluminum chloride (Q cadmium(II) chloride and (g) potassium oxide. 

C03-0105. The line stmctures of three different plant growth hormones are given below. For each one, write the chemical formula for the compound and calculate its molar mass. 

We can use the ideal gas equation to calculate the molar mass. Then we can use the molar mass to identify the correct molecular formula among a group of possible candidates, knowing that the products must contain the same elements as the reactants. The problem involves a chemical reaction, so we must make a connection between the gas measurements and the chemistry that takes place. Because the reactants and one product are known, we can write a partial equation that describes the chemical reaction CaC2(. ) +H2 0(/) Gas -I- OH" ((2 q) In any chemical reaction, atoms must be conserved, so the gas molecules can contain only H, O, C, and/or Ca atoms. To determine the chemical formula of the gas, we must find the combination of these elements that gives the observed molar mass. 

These five guidelines allow us to figure out the frameworks of many compounds from their chemical formulas. When the guidelines do not provide an unambiguous framework, however, we need additional stmctural information. For example, the chemical formula of benzene is Cg Hg. The guidelines tell us that the six H atoms are in outer positions but provide no help in deducing the rest of the connections. In fact, there are several possible frameworks for the chemical formula Cg Hg. We must be told that the six C atoms of benzene form a ring, with one H bonded to each C, before we can write the framework for this molecule. 

Write the chemical formula and the Lewis structure and draw a molecular picture of each of the following (a) the conjugate acid of NH3 (b) the conjugate base of HCO2 H and (c) the conjugate acid of HSOq-. 

C18-0085. Write the chemical formulas, including charge, of the complexes that form between the following metal cations and ligands (a) Fe " and CN", coordination number = 6 (b) and NH3, coordination number = 4 and (c) and ethylenediamine (en), coordination number = 6. 

Frankland discovered the fundamental principle of valency—the combining power of atoms to form compounds. He gave the chemical bond its name and popularized the notation we use today for writing chemical formulas. He codiscovered helium, helped found synthetic organic and structural chemistry, and was the father of organometallic chemistry. He was also the first person to thoroughly analyze the gases from different types of coal and—dieters take note—the first to measure the calories in food. 

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