Question: Consider the oxidation–reduction reaction 2Na + F2

> What does temperature measure? Are the molecules in a beaker of warm water moving at the same speed as the molecules in a beaker of cold water? Explain. What is heat? Is heat the same as temperature?

> What is potential energy? What is kinetic energy? What do we mean by the law of conservation of energy? What do scientists mean by work? Explain what scientists mean by a state function and give an example of one.

> Solid calcium carbide (CaC2) reacts with liquid water to produce acetylene gas (C2H2) and aqueous calcium hydroxide. a. Write the balanced equation for the reaction that is occurring, including all phases. b. If a 100.0-g sample of calcium carbide (CaC

> For each of the following balanced equations, calculate how many grams of each product would form if 12.5 g of the reactant listed first in the equation reacts completely (there is an excess of the second reactant). a. SiC(s) + 2Cl2(g) SiCl

> A compound was analyzed and was found to have the following percent composition by mass: sodium, 43.38%; carbon, 11.33%; oxygen, 45.29%. Determine the empirical formula of the compound.

> Consider 2.45-g samples of each of the following elements or compounds. Calculate the number of moles of the element or compound present in each sample. a. Fe2O3(s) b. P4(s) c. Cl2(g) d. Hg2O(s) e. HgO(s) f. Ca(NO3)2(s) g. C3H8(g) h. Al2(SO4)3(s)

> What do we mean by the theoretical yield for a reaction? What is meant by the actual yield? Why might the actual yield for an experiment be less than the theoretical yield? Can the actual yield be more than the theoretical yield?

> After studying a few chapters of this text, and perhaps having done a few lab experiments and taken a few quizzes in chemistry, you are probably sick of hearing the term significant figures. Most chemistry teachers make a big deal about significant figur

> For a balanced chemical equation of your choice, and using 25.0 g of each of the reactants in your equation, illustrate and explain how you would determine which reactant is the limiting reactant. Indicate clearly in your discussion how the choice of lim

> What is meant by a limiting reactant in a particular reaction? In what way is the reaction “limited”? What does it mean to say that one or more of the reactants are present in excess? What happens to a reaction when the limiting reactant is used up?

> In the practice of chemistry one of the most important calculations concerns the masses of products expected when particular masses of reactants are used in an experiment. For example, chemists judge the practicality and efficiency of a reaction by seein

> Consider the unbalanced equation for the combustion of propane: C3H8(g) + O2(g) / CO2(g) + H2O(g) First, balance the equation. Then, for a given amount of propane, write the mole ratios that would enable you to calculate the number of moles of each pro

> Balanced chemical equations give us information in terms of individual molecules reacting in the proportions indicated by the coefficients, and also in terms of macroscopic amounts (that is, moles). Write a balanced chemical equation of your choice, and

> Rather than giving students straight percent composition data for determining the empirical formula of a compound (see Question 7), sometimes chemistry teachers will try to emphasize the experimental nature of formula determination by converting the perc

> When chemistry teachers prepare an exam question on determining the empirical formula of a compound, they usually take a known compound and calculate the percent composition of the compound from the formula. They then give students this percent compositi

> Define, compare, and contrast what are meant by the empirical and molecular formulas for a substance. What does each of these formulas tell us about a compound? What information must be known for a compound before the molecular formula can be determined?

> What is meant by the percent composition by mass for a compound? Describe in general terms how this information is obtained by experiment for new compounds. How can this information be calculated for known compounds?

> Define molar mass. Using H3PO4 as an example, calculate the molar mass from the atomic masses of the elements.

> Consider the amino acids alanine, cysteine, and asparagine. Which of these contain polar side chains? Why?

> How do we know that 16.00 g of oxygen contains the same number of atoms as does 12.01 g of carbon, and that 22.99 g of sodium contains the same number of atoms as each of these? How do we know that 106.0 g of Na2CO3 contains the same number of carbon ato

> Using the negative polyatomic ions listed in Table 5.4, write formulas for each of their sodium and calcium compounds. From table 5.4: lon Name lon Name NH," ammonium co, carbonate hydrogen carbonate (bicarbonate is a widely NO, nitrite HCO, NO, nit

> Give the name of each of the following polyatomic ions. a. CO32- b. MnO4- c. NO3- d. HSO4- e. C2H3O2- f. CrO42- g. OH- h. ClO2- i. HCO3- j. HPO42-

> For each of the following simple ions, indicate the number of protons and electrons the ion contains. a. Mg2+ b. Fe2+ c. Fe3+ d. F- e. Ni2+ f. Zn2+ g. Co3+ h. N3- i. S2- j. Rb+ k. Se2- l. K+

> What simple ion does each of the following elements most commonly form? a. Sr b. I c. Ag d. Al e. Se f. O g. Rb h. N i. K j. Mg k. S l. P m. Cl

> How many electrons, protons, and neutrons are found in isolated atoms having the following atomic symbols? a. 8 17

> Give the names of several steroid sex hormones, and indicate their functions in the body.

> Using the periodic table shown in Fig. 4.9, for each of the following symbols, write the name of the element and its atomic number. a. Mg b. Ga c. Sn d. Sb e. Sr f. Si g. Cs h. Ca i. Cr j. Co k. Cu l. Ag m. U n. As o. At p. Ar q. Zn r

> Your text indicates that the Group 1, Group 2, Group 7, and Group 8 elements all have “family” names (alkali metals, alkaline earth metals, halogens, and noble gases, respectively). Without looking at your textbook, name as many elements in each family a

> What is a micelle? How do the micelles formed by soap molecules suspend greasy dirt in a solution?

> Consider the 20 most common amino acids shown in Fig. 21.2. Although you may not be asked to memorize all these structures, it will help your study if you are familiar with them. Choose any five of the amino acids and sketch their structures. Also sketch

> Describe the mechanism by which a soap is able to remove greasy dirt from clothing.

> Using the general formula for a triglyceride, write an equation showing the process of saponification. What is a soap?

> Referring to Table 21.5, give an example of a saturated and an unsaturated fatty acid. Are triglycerides from animal sources generally saturated or unsaturated? Are triglycerides from plant sources generally saturated or unsaturated? From table 21.5:

> Complete the following table by giving the symbol, name, atomic number, and/or group (family) number as required. Atomic Group Symbol Name Number Number aluminum 86 S Sr bromine 6. 56 Ra sodium potassium Ge chlorine

> What is an acid? How are acids that do not contain oxygen named? Give several examples. Describe the naming system for the oxyacids. Give examples of a series of oxyacids illustrating this system.

> What is an oxyanion? What special system is used in a series of related oxyanions that indicates the relative number of oxygen atoms in each ion? Give examples.

> What is a polyatomic ion? Without consulting a reference, list the formulas and names of at least ten polyatomic ions. When writing the overall formula of an ionic compound involving polyatomic ions, why are parentheses used around the formula of a polya

> The text states that the key to DNA’s functioning is its doublehelical structure with complementary bases on the two strands. Explain, with particular reference to how DNA is replicated.

> Describe the double-helical structure of DNA. What type of bonding occurs within the chain of each strand of the double helix? What type of bonding exists between strands to link them together?

> Describe the system used to name Type III binary compounds (compounds of nonmetallic elements). Give several examples illustrating the method. How does this system differ from that used for ionic compounds? How is the system for Type III compounds simila

> What general functions do fibrous and globular proteins have in the body?

> When writing the name of an ionic compound, which is named first, the anion or the cation? Give an example. What ending is added to the root name of an element to show that it is a simple anion in a Type I ionic compound? Give an example. What two system

> What principle do we use in writing the formula of an ionic compound such as NaCl or MgI2? How do we know that two iodide ions are needed for each magnesium ion, whereas only one chloride ion is needed per sodium ion?

> What are some general physical properties of ionic compounds such as sodium chloride? How do we know that substances such as sodium chloride consist of positively and negatively charged particles? If ionic compounds are made up of electrically charged pa

> What are ions? How are ions formed from atoms? Do isolated atoms form ions spontaneously? To what do the terms cation and anion refer? In terms of subatomic particles, how is an ion related to the atom from which it is formed? Does the nucleus of an atom

> Are most elements found in nature in the elemental or the combined form? Why? Name several elements that are usually found in the elemental form.

> Starch and cellulose both are polymers of glucose that are synthesized by plants. What do plants use starch for? What do they use cellulose for? Why is starch digestible by humans, but cellulose is not digestible?

> What are isotopes? To what do the atomic number and the mass number of an isotope refer? How are specific isotopes indicated symbolically (give an example and explain)? Do the isotopes of a given element have the same chemical and physical properties? Ex

> What is meant by a nuclear atom? Describe the points of Rutherford’s model for the nuclear atom and how he tested this model. Based on his experiments, how did Rutherford envision the structure of the atom? How did Rutherford’s model of the atom’s struct

> The common strong acids are HCl, HNO3, and H2SO4, whereas NaOH and KOH are the common strong bases. Write the neutralization reaction equations for each of these strong acids with each of these strong bases in aqueous solution.

> The element carbon undergoes many inorganic reactions, as well as being the basis for the field of organic chemistry. Write balanced chemical equations for the reactions of carbon described below. a. Carbon burns in an excess of oxygen (for example, in

> What is a compound? What is meant by the law of constant composition for compounds and why is this law so important to our study of chemistry?

> Calculate the molarities of the solutions resulting when the indicated dilutions are made. Assume that the volumes are additive. a. 25 mL of water is added to 12.5 mL of 1.515 M NaOH solution. b. 75.0 mL of 0.252 M HCl is diluted to a volume of 225 mL.

> Calculate the indicated quantity for each solution. a. The mass of solute present in 235 mL of 0.251 M NaOH solution. b. The molarity of the solution when 0.293 mole of KNO3 is dissolved in water to a final volume of 125 mL. c. The number of moles of

> Calculate the indicated quantity for each solution. a. The percent by mass of solute when 2.05 g of NaCl is dissolved in 19.2 g of water. b. The mass of solute contained in 26.2 g of 10.5% CaCl2 solution. c. The mass of NaCl required to prepare 225 g

> If an electric current is passed through molten sodium chloride, elemental chlorine gas is generated as the sodium chloride is decomposed. 2NaCl(l) 2Na(s) + Cl2(g) What volume of chlorine gas measured at 767 mm Hg at 25 °C would be generate

> When calcium carbonate is heated strongly, it evolves carbon dioxide gas. CaCO3(s) CaO(s) + CO2(g) If 1.25 g of CaCO3 is heated, what mass of CO2 would be produced? What volume would this quantity of CO2 occupy at STP?

> a. If the temperature of a 255-mL sample of gas is increased from 35 °C to 55 °C at constant pressure, what will be the new volume of the gas sample? b. If a 325-mL sample of gas at 25 °C is immersed in liquid nitrogen at –196 °C, what will be the new v

> a. If the pressure on a 125-mL sample of gas is increased from 755 mm Hg to 899 mm Hg at constant temperature, what will the volume of the sample become? b. If a sample of gas is compressed from an initial volume of 455 mL at 755 mm Hg to a final volume

> The concentration of a solution may be expressed in various ways. Suppose 5.00 g of NaCl were dissolved in 15.0 g of water, which resulted in 16.1 mL of solution after mixing. Explain how you would calculate the mass percent of NaCl and the molarity of N

> What happens to a gas sample when it is collected by displacement of, or by bubbling through, water? How is this taken into account when calculating the pressure of the gas?

> Write expressions for Ksp for each of the following sparingly soluble substances. a. Cu(OH)2(s) b. Co2S3(s) c. Hg2(OH)2(s) d. CaCO3(s) e. Ag2CrO4(s) f. Hg(OH)2(s)

> Without consulting your textbook or notes, state as many points as you can of Dalton’s atomic theory. Explain in your own words each point of the theory.

> You have learned the basic way in which scientists analyze problems, propose models to explain the systems under consideration, and then experiment to test their models. Suppose you have a sample of a liquid material. You are not sure whether the liquid

> Suppose that for the following reaction Br2( g) + Cl2( g) ⇌ 2BrCl( g) it is determined that, at a particular temperature, the equilibrium concentrations are as follows: [Br2( g)] = 7.2 * 10-8 M, [Cl2( g)] = 4.3 3 10-6 M, [BrCl( g)] = 4.9 3 10-4 M. Calcu

> Write the equilibrium constant expression for each of the following reactions. a. 4NO( g) ⇌ 2N2O( g) + O2( g) b. 4PF3( g) ⇌ P4(s) + 6F2( g) c. CO( g) + 3H2( g) ⇌ CH4( g) + H2O( g) d. 2BrF5( g) ⇌ Br2( g) + 5F2( g) e. S(s) + 2HCl( g) ⇌ H2S( g) + Cl2

> What is a phospholipid? How does the structure of a phospholipid differ from that of a triglyceride? What is the function of the phospholipid lecithin?

> Describe the structure of a wax. Where do waxes occur naturally in living creatures, and what function do they serve?

> Identify the Brønsted–Lowry conjugate acid–base pairs in each of the following. a. NH3(aq) + H2O( l ) ⇌ NH4+(aq) + OH-(aq) b. H2SO4(aq) + H2O( l ) ⇌ HSO4-(aq) + H3O+(aq) c. O2-(s) + H2O( l ) ⇌ 2OH-(aq) d. NH2-(aq) + H2O( l ) ⇌ NH3(aq) + OH-(aq)

> Although both starch and cellulose are polymers of glucose, starch is digestible by humans and cellulose is not. How do the structures of these polysaccharides differ, resulting in their different digestibility?

> What general name is given to sugars containing five carbon atoms? six carbon atoms? three carbon atoms?

> What is meant by inhibition of an enzyme? What happens when an enzyme is irreversibly inhibited?

> Describe the structure of the protein collagen. What function does collagen have in the body?

> What specific protein carries oxygen from the lungs to other body tissues?

> Sketch the straight-chain representations of the aldehyde sugar glucose and of the ketone sugar fructose. Circle the aldehyde or ketone functional group in your structures.

> List three structural uses of proteins in the body.

> How many possible primary structures exist for a small polypeptide containing four individual amino acids?

> Describe the secondary protein structure known as the a-helix. What types of proteins have this secondary structure?

> Cholic acid and other bile acids act as agents during digestion, helping to break fats up into smaller droplets that can then be acted on by enzymes.

> Referring to Fig. 21.25, what is a common characteristic among the structures of steroids? From figure 21.25: CH3 CH, CH3 C=0 CH, CH3 CH3 CH3 CH1 HO cholesterol progesterone CH3 CH3 CH, CH3 OH CH3 CH3 HO HO vitamin D3 estradiol CH2OH 0-C-CH3 CH C=C-

> The starting material in the body for the synthesis of other steroids is .

> Cholesterol, adrenocorticoid hormones, sex hormones, and bile acids make up what class of lipids?

> The aggregations of fatty acid anions that form when a soap is added to water are called .

> Fatty acid anions make good soaps because they have both a portion that is miscible with water and a portion that is miscible with grease.

> The process of involves treating a fat with sodium hydroxide so that the fatty acids present are converted to their sodium salts.

> Describe the lock-and-key model for enzymes. Why are the shapes of the enzyme and its substrate important in this model? What does it mean to say that an enzyme is inhibited by a particular molecule? What happens if this inhibition is irreversible? Can y

> Vegetable oils tend to contain fatty acids, whereas animal fats tend to be .

> are esters of the polyhydroxyalcohol glycerol with long-chain carboxylic acids.

> Write the amino acid sequences possible for a tripeptide containing the amino acids cys, ala, and phe, with each amino acid being used only once in each tripeptide.

> The codes specified by are responsible for assembling the correct primary structure of proteins.

> During protein synthesis, RNA molecules attach to and transport specific amino acids to the appropriate position on the pattern provided by RNA molecules.

> A given segment of the DNA molecule, which contains the molecular coding for a specific protein to be synthesized, is referred to as a .

> In a strand of normal DNA, the base is always found paired with the base adenine, whereas is always found paired with cytosine.

> The bases on opposite strands of DNA are said to be to each other, which means the bases fit together specifically by hydrogen bonding to one another.

> The basic linkage in DNA or RNA between the sugar molecule and phosphoric acid is a phosphate linkage.

> The pentose deoxyribose is found in DNA, whereas is found in RNA.

> Which of the following formula–name pairs are incorrect? Explain why for each case. a. Ag(NO3)2 silver nitrate b. Fe2Cl ferrous chloride c. NaH2PO4 sodium hydrogen phosphate d. NH4S ammonium sulfide e. KC2H3O2 potassium acetate f. Ca(ClO4)2 calcium

> RNA molecules have molar masses in the range of 20,000 to 40,000 g/mol. How does this molar-mass range compare to the molar mass of DNA?

> The substance in the nucleus of the cell that stores and transmits genetic information is DNA, which stands for .

> For Exercises 55–76 choose one of the following terms to match the description given. a. aldohexose b. antibody c. cellulose d. CH2O e. cysteine f. denaturation g. disaccharides h. disulfide i. DNA j. enzymes k. fibrous l. globular m. glycog