A widely used weather instrument called a barometer can be built from a long, thin tube of glass that is sealed at one end. The tube is completely filled with mercury and then inverted into a small pool of mercury. The level of the mercury inside the tube drops initially but then stabilizes at some height. A measure of the height of the column of mercury once it stabilizes is a measure of pressure in mm Hg (or torr). Which of the following is the best explanation of how this barometer works? a. Air pressure outside the tube (pressure of the atmosphere) counterbalances the weight of the mercury inside the tube. b. Air pressure inside the tube causes the mercury to move in the tube until the air pressure inside and outside the tube are equal. c. Air pressure outside the tube causes the mercury to move in the tube until the air pressure inside and outside the tube are equal. d. The vacuum that is formed at the top of the tube of mercury (once the mercury level in the tube has dropped some) holds up the mercury. e. I have no idea how a barometer works.
> Describe a simple mercury barometer. How is such a barometer used to measure the pressure of the atmosphere?
> Why are the dipole–dipole interactions between polar molecules not important in the vapor phase?
> What mass of neon gas is required to fill a 5.00-L container to a pressure of 1.02 atm at 25 °C?
> If two gases that do not react with each other are placed in the same container, they will completely with each other.
> If 2.71 g of argon gas occupies a volume of 4.21 L, what volume will 1.29 moles of argon occupy under the same conditions?
> If 3.25 moles of argon gas occupies a volume of 100. L at a particular temperature and pressure, what volume does 14.15 moles of argon occupy under the same conditions?
> On the basis of their electron configurations, predict the formula of the simple binary ionic compound likely to form when the following pairs of elements react with each other. a. aluminum and bromine b. aluminum and oxygen c. aluminum and phosphorus
> If 0.00901 mole of neon gas at a particular temperature and pressure occupies a volume of 242 mL, what volume would 0.00703 mole of neon occupy under the same conditions?
> If 5.12 g of oxygen gas occupies a volume of 6.21 L at a certain temperature and pressure, what volume will 25.0 g of oxygen gas occupy under the same conditions?
> If a 0.475-L sample of neon gas is heated from 27 °C to 82 °C at constant pressure, what will be the volume of the sample at the higher temperature?
> If a gaseous mixture is made of 3.50 g of He and 5.75 g of Ar in an evacuated 2.05-L container at 25 °C, what will be the partial pressure of Ar in the container?
> An expandable vessel contains 729 mL of gas at 22 °C. What volume will the gas sample in the vessel have if it is placed in a boiling water bath (100. °C)?
> A sample of a gas at 0.780 atm occupies a volume of 0.501 L. If the temperature remains constant, what will be the new pressure if the volume increases to 0.794 L?
> If the pressure on a 2.10 * 104 mL sample of gas is doubled at constant temperature, what will be the new volume of the gas?
> Convert the following pressures into mm Hg. a. 0.903 atm b. 2.1240 * 106 Pa c. 445 kPa d. 342 torr
> If 0.214 mole of argon gas occupies a volume of 652 mL at a particular temperature and pressure, what volume would 0.375 mole of argon occupy under the same conditions?
> If 10.0 g of liquid helium at 1.7 K is completely vaporized, what volume does the helium occupy at STP?
> On the basis of their electron configurations, predict the formula of the simple binary ionic compounds likely to form when the following pairs of elements react with each other. a. aluminum, Al, and sulfur, S b. radium, Ra, and oxygen, O c. calcium,
> At what temperature does 4.00 g of helium gas have a pressure of 1.00 atm in a 22.4-L vessel?
> Suppose two separate 100.0-L tanks are to be filled, one with helium and one with hydrogen. What mass of each gas is needed to produce a pressure of 2.70 atm in its respective tank at 24 °C?
> What is the pressure inside a 10.0-L flask containing 14.2 g of N2 at 26 °C?
> You have 1 mole of an ideal gas in a balloon. How must the volume change so that the pressure in the balloon doubles and the temperature in °C is halved (assume the temperature is a positive value)? a. The volume must decrease by more than half the orig
> Carbon dioxide gas, in the dry state, may be produced by heating calcium carbonate. CaCO3(s) / CaO(s) + CO2(g) What volume of CO2, collected dry at 55 °C and a pressure of 774 torr, is produced by complete thermal decomposition of 10.0 g of CaCO3?
> The formulas of several chemical substances are given in the table below. For each substance in the table, give its chemical name and predict its molecular structure. Formula Compound Name Molecular Structure CO, NH3 SO3 H,0 ClO,-
> Which of the following compounds or ions exhibit resonance? a. O3 b. CNO- c. AsI3 d. CO32- e. AsF3
> Write electron configurations for the most stable ion formed by each of the following elements. Do not use the noble gas notation. Write out the complete electron configuration. Electron Configuration of the Most Stable lon Element Na K Li Cs
> For a mixture of gases in the same container, the total pressure exerted by the mixture of gases is the of the pressures that those gases would exert if they were alone in the container under the same conditions.
> List the bonds P-Cl, P-F, O-F, and Si-F from least polar to most polar.
> For each of the following sets of volume/temperature data, calculate the missing quantity after the change is made. Assume that the pressure and the amount of gas remain the same. a. V = 9.14 L at 24 °C; V =? at 48 °C b. V = 24.9 mL at –12 °C; V = 49.9
> Compare the electronegativities of each pair of atoms. State the element of each pair that has the greater electronegativity. Symbol for Element with Greater Electronegativity Pair P and CI Ca and N N and As
> Classify the bonding in each of the following molecules as ionic, polar covalent, or nonpolar covalent. a. H2 b. K3P c. NaI d. SO2 e. HF f. CCl4 g. CF4 h. K2S
> When doing any calculation involving gas samples, we must express the temperature in terms of the temperature scale.
> What is the expected ground-state electron configuration for the element with one unpaired 5p electron that forms a covalent compound with fluorine?
> Using the VSEPR theory, predict the molecular structure of each of the following molecules or ions containing multiple bonds. a. CO32- b. HNO3 (hydrogen is bonded to oxygen) c. NO2- d. C2H2
> Using the VSEPR theory, predict the molecular structure of each of the following molecules or ions containing multiple bonds. a. SO2 b. SO3 c. HCO3- (hydrogen is bonded to oxygen) d. HCN
> For each of the following molecules, indicate the bond angle expected between the central atom and any two adjacent chlorine atoms. a. Cl2O b. CCl4 c. BeCl2 d. BCl3
> Using the VSEPR theory, predict the molecular structure of each of the following polyatomic ions. a. chlorate ion b. chlorite ion c. perchlorate ion
> Using the VSEPR theory, predict the molecular structure of each of the following molecules. a. Cl2O b. OF2 c. SiCl4
> For the indicated atom in each of the following molecules, give the number and the arrangement of the electron pairs around that atom. a. C in CCl4 b. Ge in GeH4 c. B in BF3
> For each of the following sets of volume/temperature data, calculate the missing quantity. Assume that the pressure and the mass of gas remain constant. a. V = 25.0 L at 0 °C; V = 50.0 L at? °C b. V = 247 mL at 25 °C; V = 255 mL at? °C c. V = 1.00 mL
> Sulfur trioxide, SO3, is produced in enormous quantities each year for use in the synthesis of sulfuric acid. S(s) + O2(g) SO2(g) 2SO2(g) + O2(g) 2SO3(g) What volume of O2(g) at 350. °C and a pressure of 5.25 atm is nee
> Chemicals placed in a microwave oven and exposed to microwave radiation can increase in temperature if they possess a net dipole moment. Which of the following molecules can get hot in an operating microwave oven? CCl4, H2O, HCl, BH3, CO2
> Write a Lewis structure for each of the following simple molecules. Show all bonding valence electron pairs as lines and all nonbonding valence electron pairs as dots. For those molecules that exhibit resonance, draw the various possible resonance forms.
> Select which of the following ions has the Lewis structure: a. B22- b. C22- c. N22- d. O22- e. F22- [:X-X:12-
> Consider the following reaction: Zn(s)+ 2HCl(aq) ZnCl2(aq) + H2(g) What mass of zinc metal should be taken so as to produce 125 mL of H2 measured at STP when reacted with excess hydrochloric acid?
> Welders commonly use an apparatus that contains a tank of acetylene (C2H2) gas and a tank of oxygen gas. When burned in pure oxygen, acetylene generates a large amount of heat. 2C2H2(g) + 5O2(g) / 2H2O(g) + 4CO2(g) What volume of carbon dioxide gas at ST
> Write the Lewis structure for each of the following atoms. a. He (Z = 2) b. Br (Z = 35) c. Sr (Z = 38) d. Ne (Z = 10) e. I (Z = 53) f. Ra (Z = 88)
> For each of the following pairs, indicate which is smaller. a. Rb+ or Na+ b. Mg2+ or Al3+ c. F- or I- d. Na+ or K+
> Which noble gas has the same electron configuration as each of the ions in the following compounds? a. calcium bromide, CaBr2 b. aluminum selenide, Al2Se3 c. strontium oxide, SrO d. potassium sulfide, K2S
> For each of the following sets of volume/temperature data, calculate the missing quantity. Assume that the pressure and the mass of gas remain constant. a. V = 2.01 * 102 L at 1150 °C; V = 5.00 L at ? °C b. V = 44.2 mL at 298 K; V = ? at 0 K c. V = 44
> What simple ion does each of the following elements most commonly form? a. sodium b. iodine c. potassium d. calcium e. sulfur f. magnesium g. aluminum h. nitrogen
> Which of the following contains a metal ion that does not have a noble gas electron configuration? AgCl, BaCl2, TiO2, ScF3, KNO3
> For each of the following bonds, draw a figure indicating the direction of the bond dipole, including which end of the bond is positive and which is negative. a. N-Cl b. N-P c. N-S d. N-C
> The electrons involved in a C-F bond could be considered a. closer to C because carbon has a larger radius and thus exerts greater control over the shared electrons. b. closer to F because fluorine has a higher electronegativity than carbon. c. closer
> Consider the following unbalanced chemical equation for the combination reaction of sodium metal and chlorine gas: Na(s) + Cl2(g) / NaCl(s) What volume of chlorine gas, measured at STP, is necessary for the complete reaction of 4.81 g of sodium metal?
> Which of the following molecules contain polar covalent bonds? a. carbon monoxide, CO b. chlorine, Cl2 c. iodine monochloride, ICl d. phosphorus, P4
> On the basis of the electronegativity values given in Fig. 12.3, indicate whether each of the following bonds would be expected to be ionic, covalent, or polar covalent. a. H-O b. O-O c. H-H d. H-Cl
> For each of the following pairs of elements, identify which element would be expected to be more electronegative. It should not be necessary to look at a table of actual electronegativity values. a. Be or Ba b. N or P c. F or Cl
> A(n) chemical bond represents the equal sharing of a pair of electrons between two nuclei.
> Which of the following statements is false concerning bonding? a. Elements with extremely different electronegativities tend to form ionic bonds with each other. b. In an N-O bond, electron density is greater near the O atom. c. An N-O bond is an exam
> Which simple ion would each of the following elements be expected to form? What noble gas has an analogous electron configuration to each of the ions? a. chlorine, Z = 17 b. strontium, Z = 38 c. oxygen, Z = 8 d. rubidium, Z = 37
> In each case, which of the following pairs of bonded elements forms the more polar bond? a. Br-Cl or Br-F b. As-S or As-O c. Pb-C or Pb-Si
> Arrange the following bonds from the least polar to the most polar bond: C-F, Na-F, Ga-F, Si-F
> The geometric arrangement of electron pairs around a given atom is determined principally by the tendency to minimize between the electron pairs.
> In ionic bonding, a. the electrons are shared between the atoms. b. the process of forming an ionic bond is highly endothermic overall. c. the bonding that occurs is usually between two nonmetal atoms. d. a noble gas configuration is formed for each
> Consider the following order: Li < N < F. For which of the following properties does the order show the correct trend? a. size b. electronegativity c. metallic character d. number of unpaired electrons e. More than one of the above properties (a–d)
> A mathematical expression that summarizes Avogadro’s law is .
> The “Chemistry in Focus” segment Taste—It’s the Structure That Counts discusses artificial sweeteners. What are the expected bond angles around the nitrogen atom in aspartame?
> For each of the following molecules or ions, indicate the bond angle expected between the central atom and any two adjacent chlorine atoms. a. Cl2O b. NCl3 c. CCl4 d. C2Cl4
> For each of the following molecules or ions, indicate the bond angle expected between the central atom and any two adjacent hydrogen atoms. a. H2O b. NH3 c. NH4+ d. CH4
> What conditions are considered “standard temperature and pressure” (STP) for gases? Suggest a reason why these particular conditions might have been chosen for STP.
> Explain how the atoms in covalent molecules achieve electron configurations similar to those of the noble gases. How does this differ from the situation in ionic compounds?
> Using the VSEPR theory, predict the molecular structure of each of the following polyatomic ions. a. sulfate ion, SO42- b. phosphate ion, PO43- c. ammonium ion, NH4+
> Using the VSEPR theory, predict the molecular structure of each of the following molecules. a. CBr4 b. PH3 c. OCl2
> Using the VSEPR theory, predict the molecular structure of each of the following molecules. a. NCl3 b. H2Se c. SiCl4
> For the indicated atom in each of the following molecules or ions, give the number and arrangement of the electron pairs around that atom. a. S in SO32- b. S in HSO3- c. S in HS-
> Temperature is a measure of the average of the molecules in a sample of gas.
> Although both the BF3 and NF3 molecules contain the same number of atoms, the BF3 molecule is flat, whereas the NF3 molecule is trigonal pyramidal. Explain.
> What do we assume about the volume of the actual molecules themselves in a sample of gas, compared to the bulk volume of the gas overall? Why?
> Why are all diatomic molecules linear, regardless of the number of valence electron pairs on the atoms involved?
> How is the structure around a given atom related to repulsion between valence electron pairs on the atom?
> At conditions of constant temperature and pressure, the volume of a sample of ideal gas is proportional to the number of moles of gas present.
> For each of the following sets of volume/temperature data, calculate the missing quantity after the change is made. Assume that the pressure and the amount of gas remain the same. a. V = 2.03 L at 24 °C; V = 3.01 L at? °C b. V = 127 mL at 273 K; V =? m
> Why is the geometric structure of a molecule important, especially for biological molecules?
> What is the geometric structure of the SiF4 molecule? How many pairs of valence electrons are present on the silicon atom of SiF4? What are the approximate F-Si-F bond angles in SiF4?
> What is the geometric structure of the boron trifluoride molecule, BF3? How many pairs of valence electrons are present on the boron atom in BF3? What are the approximate F-B-F bond angles in BF3?
> What is the geometric structure of the ammonia molecule? How many pairs of electrons surround the nitrogen atom in NH3? What is the approximate H-N-H bond angle in ammonia?
> What is the geometric structure of the water molecule? How many pairs of valence electrons are there on the oxygen atom in the water molecule? What is the approximate H-O-H bond angle in water?
> Suppose a 125-mL sample of argon is cooled from 450 K to 250 K at constant pressure. What will be the volume of the sample at the lower temperature?
> Suppose 1.25 L of argon is cooled from 291 K to 78 K. What will be the new volume of the argon sample?
> Suppose a 375-mL sample of neon gas at 78 °C is cooled to 22 °C at constant pressure. What will be the new volume of the neon sample?
> A mathematical expression that summarizes Charles’s law is .
> The “Chemistry in Focus” segment Hiding Carbon Dioxide discusses attempts at sequestering (storing) underground CO2 produced at power plants so as to diminish the greenhouse effect. Draw all resonance structures of the CO2 molecule.
> When 50 mL of liquid water at 25 °C is added to 50 mL of ethanol (ethyl alcohol), also at 25 °C, the combined volume of the mixture is considerably less than 100 mL. Give a possible explanation.
> Figure 13.1 shows an experiment that can be used effectively to demonstrate the pressure exerted by the atmosphere. Write an explanation of this experiment to a friend who has not yet taken any science courses to help him understand the concept of atmosp
> The “Chemistry in Focus” segment Broccoli—Miracle Food? discusses the health benefits of eating broccoli and gives a Lewis structure for sulforaphane, a chemical in broccoli. Draw possible resonance structures for sulforaphane.
> Which of the following species exhibits resonance? CH4, OCl2, NO2-, HCN (C is the central atom)
> Suppose a 24.3-mL sample of helium gas at 25 °C and 1.01 atm is heated to 50. °C and compressed to a volume of 15.2 mL. What will be the pressure of the sample?
> Which flask will have the higher pressure: a 5.00-L flask containing 4.15 g of helium at 298 K, or a 10.0-L flask containing 56.2 g of argon at 303 K?
> What pressure exists in a 200-L tank containing 5.0 kg of neon gas at 300. K?
