(a) What is the specific heat of liquid water? (b) What is the molar heat capacity of liquid water? (c) What is the heat capacity of 185 g of liquid water? (d) How many kJ of heat are needed to raise...
(a) Which substance in Table 5.2 requires the smallest amount of energy to increase the temperature of 50.0 g of that substance by 10 K? (b) Calculate the energy needed for this temperature change.
(a) When a 4.25-g sample of solid ammonium nitrate dissolves in 60.0 g of water in a coffee-cup calorimeter (Figure 5.18), the temperature drops from 22.0 C to 16.9 C. Calculate H (in kJ/mol NH4NO3)...
(a) Why are tables of standard enthalpies of formation so useful? (b) What is the value of the standard enthalpy of formation of an element in its most stable form? (c) Write the chemical equation...
Many portable gas heaters and grills use propane, C3H8(g), as a fuel. Using standard enthalpies of formation, calculate the quantity of heat produced when 10.0 g of propane is completely combusted in...
Ethanol (C2H5OH) is currently blended with gasoline as an automobile fuel. (a) Write a balanced equation for the combustion of liquid ethanol in air. (b) Calculate the standard enthalpy change for...
(a) Why are fats well suited for energy storage in the human body? (b) A particular chip snack food is composed of 12% protein, 14% fat, and the rest carbohydrate. What percentage of the calorie...
A pound of plain M&M candies contains 96 g fat, 320 g carbohydrate, and 21 g protein. What is the fuel value in kJ in a 42-g (about 1.5 oz) serving? How many Calories does it provide?
An aluminum can of a soft drink is placed in a freezer. Later, you find that the can is split open and its contents frozen. Work was done on the can in splitting it open. Where did the energy for...
(a) What is the octet rule? (b) How many electrons must a sulfur atom gain to achieve an octet in its valence shell? (c) If an atom has the electron configuration 1s22s22p3, how many electrons must...
(a) Write the electron configuration for the element titanium, Ti. How many valence electrons does this atom possess? (b) Hafnium, Hf, is also found in group 4B. Write the electron configuration for...
(a) What is meant by the term covalent bond? (b) Give three examples of covalent bonding. (c) A substance XY, formed from two different elements, boils at -33oC. Is XY likely to be a covalent or an...
A sample of gas is contained in a cylinder-and-piston arrangement. It undergoes the change in state shown in the drawing. (a) Assume first that the cylinder and piston are perfect thermal insulators...
(a) Write the chemical equations that are used in calculating the lattice energy of SrCl2(s) via a Born-Haber cycle. (b) The second ionization energy of Sr(g) is 1064kJ/mol. Use this fact along with...
Acetylene (C2H2) and nitrogen (N2) both contain a triple bond, but they differ greatly in their chemical properties. (a) Write the Lewis structures for the two substances. (b) By referring to...
Average bond enthalpies are generally defined for gas-phase molecules. Many substances are liquids in their standard state. By using appropriate thermo-chemical data from Appendix C, calculate...
(a) What is meant by the term electro negativity? (b) On the Pauling scale what is the range of electro negativity values for the elements? (c) Which element has the greatest electro negativity? (d)...
(a) What is the trend in electro negativity going from left to right in a row of the periodic table? (b) How do electro negativity values generally vary going down a column in the periodic table? (c)...
The orbital diagram that follows shows the valence electrons for a 2+ ion of an element. (a) What is the element? (b) What is the electron configuration of an atom of this element? 4d
A portion of a two-dimensional "slab" of NaCl (s) is shown here (see Figure 8.3) in which the ions are numbered. (a) Of the following types of interactions (identified by color), which are attractive...
Arrange the bonds in each of the following sets in order of increasing polarity: (a) C-F, O-F, Be-F (b) O-Cl, S-Br, C-P (c) C-S, B-F, N-O
(a) When talking about atoms in a Lewis structure, what is meant by the term formal charge? (b) Does the formal charge of an atom represent the actual charge on that atom? Explain. (c) How does the...
(a) Write a Lewis structure for the phosphorus tri-fluoride molecule, PF3. Is the octet rule satisfied for all the atoms in your structure? (b) Determine the oxidation numbers of the P and F atoms....
(a) Use the concept of resonance to explain why all six C-C bonds in benzene are equal in length. (b) Are the C-C bond lengths in benzene shorter than C-C single bonds? Are they shorter than C == C...
(a) State the octet rule. (b) Does the octet rule apply to ionic as well as to covalent compounds? Explain using examples as appropriate.
In the vapor phase, BeCl2 exists as a discrete molecule. (a) Draw the Lewis structure of this molecule, using only single bonds. Does this Lewis structure satisfy the octet rule? (b) What other...
Ammonia is produced directly from nitrogen and hydrogen by using the Haber process. The chemical reaction is N2 (g) + 3H2 (g) 2NH3 (g) (a) Use Table 8.4 to estimate the enthalpy change for the...
An ionic substance of formula MX has lattice energy of 6 103 kJ/mol. Is the charge on the ion M likely to be 1+, 2+ or 3+? Explain your reasoning.
Although I3- is known, F3- is not. Using Lewis structures, explain why F3- does not form.
(a) What are valence electrons? (b) How many valence electrons does a nitrogen atom possess? (c) An atom has the electron configuration 1s22s22p63s23p2. How many valence electrons does the atom have?
(a) Triazine, C3H3N3, is like benzene except that in triazine every other C-H group is replaced by a nitrogen atom. Draw the Lewis structure(s) for the triazine molecule. (b) Estimate the...
Assume that a single cylinder of an automobile engine has a volume of 524cm3. (a) If the cylinder is full of air at 74oC and 0.980 atm, how many moles of O2 are present? (The mole fraction of O2 in...
An important reaction for the conversion of natural gas to other useful hydrocarbons is the conversion of methane to ethane. 2CH4 (g) C2H6 (g) + H2 (g) In practice, this reaction is carried out in...
The "plastic" explosive C-4, often used in action movies, contains the molecule cyclotrimethylenetrinitramine, which is often called RDX (for Royal Demolition eXplosive):...
Carbon dioxide, which is recognized as the major contributor to global warming as a "greenhouse gas," is formed when fossil fuels are combusted, as in electrical power plants fueled by coal, oil, or...
A thin glass tube 1 m long is filled with Ar gas at 1 atm, and the ends are stoppered with cotton plugs: HCl gas is introduced at one end of the tube, and simultaneously NH3 gas is introduced at the...
An herbicide is found to contain only C, H, N, and Cl. The complete combustion of a 100.0-mg sample of the herbicide in excess oxygen produces 83.16 mL of CO2 and 73.30 mL of H2O vapor at STP. A...
A 4.00-g sample of a mixture of CaO and BaO is placed in a 1.00-L vessel containing CO2 gas at a pressure of 730 torr and a temperature of 25oC. The CO2 reacts with the CaO and BaO, forming CaCO3 and...
Chlorine dioxide gas (ClO2) is used as a commercial bleaching agent. It bleaches materials by oxidizing them. In the course of these reactions, the ClO2 is itself reduced. (a) What is the Lewis...
A set of bookshelves rests on a hard floor surface on four legs, each having a cross-sectional dimension of 3.0 x 4.1 cm in contact with the floor. The total mass of the shelves plus the books...
You have a sample of gas in a container with a movable piston, such as the one in the drawing. (a) Redraw the container to show what it might look like if the temperature of the gas is increased from...
An open-end manometer containing mercury is connected to a container of gas, as depicted in Sample Exercise 10.2. What is the pressure of the enclosed gas in torr in each of the following situations?...
(a) What is an ideal gas? (b) Show how Boyle's law, Charles's law, and Avogadro's law can be combined to give the ideal-gas equation. (c) Write the ideal-gas equation, and give the units used for...
A neon sign is made of glass tubing who's inside diameter is 2.5 cm and whose length is 5.5 m. If the sign contains neon at a pressure of 1.78 torr at 35oC, how many grams of neon are in the sign?...
A scuba divers tank contains 0.29 kg of O2 compressed into a volume of 2.3 L. (a) Calculate the gas pressure inside the tank at 9oC. (b) What volume would this oxygen occupy at and 0.95 atm?
An aerosol spray can with a volume of 250 mL contain 2.30 g of propane gas (C3H8) as a propellant. (a) If the can is at 23oC, what is the pressure in the can? (b) What volume would the propane occupy...
The physical fitness of athletes is measured by "VO2 max," which is the maximum volume of oxygen consumed by an individual during incremental exercise (for example, on a treadmill). An average male...
After the large eruption of Mount St. Helens in 1980, gas samples from the volcano were taken by sampling the downwind gas plume. The unfiltered gas samples were passed over a gold coated wire coil...
The metabolic oxidation of glucose, C6H12O6, in our bodies produces CO2, which is expelled from our lungs as a gas: C6H12O6 (aq) + 6O2 (g) 6CO2 (g) + 6H2O (l) (a) Calculate the volume of dry CO2...
Acetylene gas, C2H2 (g), can be prepared by the reaction of calcium carbide with water: CaC2 (s) + 2 H2O (l) Ca (OH)2 (s) + C2H2 (g) Calculate the volume of C2H2 that is collected over water at by...
A plasma-screen TV contains thousands of tiny cells filled with a mixture of Xe, Ne, and He gases that emits light of specific wavelengths when a voltage is applied. A particular plasma cell, 0.900...
A piece of dry ice (solid carbon dioxide) with a mass of 5.50 g is placed in a 10.0-L vessel that already contains air at 705 torr and 24oC. After the carbon dioxide has totally vaporized, what is...
A sample of 5.00 mL of diethylether (C2H5OC2H5, density = 0.7134 g / mL) is introduced into a 6.00-L vessel that already contains a mixture of N2 and O2, whose partial pressures are PN2 = 0.751 atm...
A mixture of gases contains 0.75 mol N2, 0.30 mol O2, and 0.15 mol CO2. If the total pressure of the mixture is 2.15 atm, what is the partial pressure of each component?
A mixture of gases contains 10.25 g of N2, 1.83 g of H2, and 7.95 g of NH3. If the total pressure of the mixture is 1.85 atm, what is the partial pressure of each component?
A quantity of N2 gas originally held at 5.25 atm pressure in a 1.00-L container at 26oC is transferred to a 12.5-L container at 20oC .A quantity of O2 gas originally at 5.25 atm and 26oC in a 5.00-L...
A sample of 3.00 g of SO2 (g) originally in a 5.00-L vessel at 21oC is transferred to a 10.0-L vessel at 26oC. A sample of 2.35 g N2 (g) originally in a 2.50-L vessel at 20oC is transferred to this...
(a) Place the following gases in order of increasing average molecular speed at 25oC: Ne, HBr, SO2, NF3, CO. (b) Calculate the rms speed of NF3 molecules at 25oC. (c) Calculate the most probable...
As discussed in the "Chemistry Put to Work" box in Section 10.8, enriched uranium can be produced by gaseous diffusion of UF6. Suppose a process were developed to allow diffusion of gaseous uranium...
Arsenic (III) sulfide sublimes readily, even below its melting point of 320oC. The molecules of the vapor phase are found to effuse through a tiny hole at 0.28 times the rate of effusion of Ar atoms...
Based on their respective van der Waals constants (Table 10.3), is Ar or CO2 expected to behave more nearly like an ideal gas at high pressures? Explain. TABLE 10.3Van der Waals Constants for Gas...
In Sample Exercise 10.16, we found that one mole of Cl2 confined to 22.41 L at 0oC deviated slightly from ideal behavior. Calculate the pressure exerted by 1.00 mol Cl2 confined to a smaller volume,...
Arrange substances CCl4, Si, and Ar in order of increasing boiling point?
Arrange substances Ga, Ne, and Br2 in order of increasing boiling point?
(a) What is meant by the term polarizability? (b)Which of the following atoms would you expect to be most polarizable: N, P, As, Sb? Explain. (c) Put the following molecules in order of increasing...
(a) Which kind of intermolecular attractive force is shown in each case here? (b) Predict which of the four interactions is the weakest? HFNOS io (i
(a) What atoms must a molecule contain to participate in hydrogen bonding with other molecules of the same kind? (b) Which of the following molecules can form hydrogen bonds with other molecules of...
Look up and compare the normal boiling points and normal melting points of H2O and H2S. (a) Based on these physical properties, which substance has stronger intermolecular forces? What kind of...
A number of salts containing the tetrahedral polyatomic anion, BF4- , are ionic liquids, whereas salts containing the somewhat larger tetrahedral ion SO42- do not form ionic liquids? Explain this...
(a) Would you expect the viscosity of n-pentane, CH3CH2CH2CH2CH3, to be larger or smaller than the viscosity of n-hexane (3.26 10-4kg/m-s)(from Table 11.4)? (b) If you compared their viscosities at...
(a) What is the significance of the critical pressure of a substance? (b) What happens to the critical temperature of a series of compounds as the force of attraction between molecules increases? (c)...
Acetone, H3CCOCH3, has a boiling point of 56 C. Based on the data given in Figure 11.25, would you expect acetone to have a higher or lower vapor pressure than ethanol at 25 C?
(a) Place the following substances in order of increasing volatility: CH4, CBr4, CH2Cl2, CH3Cl, CHBr3, and CH2Br2. Explain. (b) How do the boiling points vary through this series?
(a) Two pans of water are on different burners of a stove. One pan of water is boiling vigorously, while the other is boiling gently. What can be said about the temperature of the water in the two...
(a) What is the significance of the critical point in a phase diagram? (b) Why does the line that separates the gas and liquid phases end at the critical point?
(a) What is the significance of the triple point in a phase diagram? (b) Could you measure the triple point of water by measuring the temperature in a vessel in which water vapor, liquid water, and...
As the intermolecular attractive forces between molecules increase in magnitude, do you expect each of the following to increase or decrease in magnitude? (a) Vapor pressure, (b) Heat of...
(a) When you exercise vigorously, you sweat. How does this help your body cool? (b) A flask of water is connected to a vacuum pump. A few moments after the pump is turned on, the water begins to...
Acetone, (CH3)2CO, is widely used as an industrial solvent. (a) Draw the Lewis structure for the acetone molecule and predict the geometry around each carbon atom. (b) Is the acetone molecule polar...
The vapor pressure of a volatile liquid can be determined by slowly bubbling a known volume of gas through it at a known temperature and pressure. In an experiment, 5.00 L of N2 gas is passed through...
(a) The density of diamond [Figure 12.30(a)] is 3.5 g/cm3 and that of graphite [Figure 12.30(b)] is Based on the structure of buckminsterfullerene (Figure 12.47), what would you expect its density to...
(a) What are the CCC bond angles in diamond? (b) What are they in graphite?
Amorphous silica, SiO2, has a density of about 2.2 g/cm3, whereas the density of crystalline quartz is 2.65g/cm3. Account for this difference in densities?
What is the minimum number of atoms that could be contained in the unit cell of an element with a body-centered cubic lattice?
The unit cell of a compound containing strontium, iron, and oxygen is shown here. (a) What type of lattice does this crystal possess (all three lattice vectors are mutually perpendicular)? (b) What...
Although polyethylene can twist and turn in random ways, the most stable form is a linear one with the carbon backbone oriented as shown in the following figure: The solid wedges in the figure...
Iridium crystallizes in a face-centered cubic unit cell that has an edge length of 3.833 . (a) Calculate the atomic radius of an iridium atom. (b) Calculate the density of iridium metal?
An element crystallizes in a body-centered cubic lattice. The edge of the unit cell is 2.86 , and the density of the crystal is 7.92 g/cm3. Calculate the atomic weight of the element?
The electronic structure of a doped semiconductor is shown here. (a) Which band, A or B, is the valence band? (b) Which band is the conduction band? (c) Which band consists of bonding molecular...
A particular form of cinnabar (HgS) adopts the zinc blende structure, Figure 12.26. The length of the unit cell edge is 5.852 . (a) Calculate the density of HgS in this form. (b) The mineral...
An ester is a compound formed by a condensation reaction between a carboxylic acid and an alcohol. Read the discussion of esters in Section 24.4 and then give an example of a reaction forming an...
Proteins are polymers formed by condensation reactions of amino acids, which have the general structure In this structure, R represents ---- H, ----CH3, or another group of atoms. Draw the general...
Are high molecular weights and a high degree of crystallinity always desirable properties of a polymer? Explain.
As mentioned in Section 12.3, Ni3Al is used in the turbines of aircraft engines because of its strength and low density. Nickel metal has a cubic close-packed structure with a face-centered cubic...
A solution contains 0.115 mol H2O and an unknown number of moles of sodium chloride. The vapor pressure of the solution at 30 oC is 25.7 torr. The vapor pressure of pure water at this temperature is...
A textbook on chemical thermodynamics states, "The heat of solution represents the difference between the lattice energy of the crystalline solid and the solvation energy of the gaseous ions." (a)...
Suppose you had a balloon made of some highly flexible semipermeable membrane. The balloon is filled completely with a 0.2 M solution of some solute and is submerged in a 0.1 M solution of the same...
A small cube of lithium (density = 0.535 g/cm3) measuring 1.0 mm on edge is added to 0.500 L of water. The following reaction occurs: 2 Li(s) + 2 H2O(l) LiOH(aq) + H2(g)
An ionic compound has a very negative in water. Would you expect it to be very soluble or nearly insoluble in water? Explain in terms of the enthalpy and entropy changes that accompany the process?
(a) Would you expect stearic acid, CH3(CH2)16COOH, to be more soluble in water or in carbon tetrachloride? Explain. (b) Which would you expect to be more soluble in water, cyclohexane or dioxane?...