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# Problems & Step-by-Step Video Solutions

Catalog of solved problems on videos. Topics include: stoichiometry, reactions in solutions, gas laws, atomic structure, bonding, kinetics, equilibrium, acid-base, thermodynamics, electrochemsitry and many more. Select MyBookTM to automatically search for solutions and tutorials in our video archive that are similar to the problems in your book. Then click on a question # to see problem and solution.

Ch. Sec.
01Chemistry Basics
01Measurments, uncertainty and errors
#Tutorial 19      Video Runtime: 07:28      Solution: PC|Mac :: Android|iOS
This lesson discusses unit conversions and the method of dimensional analysis.
#Tutorial 20      Video Runtime: 05:03      Solution: PC|Mac :: Android|iOS
This lesson discusses what the uncertainty of a measurement means and how to describe the statistical and systematic errors of a measurement.
02Atoms, Molecules, Ions
02Laws of definite proportion and multiple proportions
#02-02-00      Video Runtime: 03:01      Solution: PC|Mac :: Android|iOS

A certain element X and oxygen form four different binary compounds.  These compounds have the following compositions:

 Compound Mass of O that combines with 1.0000 g of X A B C D 0.22564 g 0.90255 g 1.3539 g 1.5795 g

(a) Show that the law of multiple proportions holds for these compounds.

(b) If the molecular formula for compound A is X2O, what are the molecular formulas for compounds B, C and D?
05Structure of the atom
#02-05-00      Video Runtime: 02:51      Solution: PC|Mac :: Android|iOS
Chlorine has two prevalent isotopes Cl-35 and Cl-37. Determine the number of protons, neutrons and electrons in each and write down its full atomic symbol.
06Molecules and ions
#Tutorial 04      Video Runtime: 05:24      Solution: PC|Mac :: Android|iOS
This lesson discusses the role of the electron in chemical reactions when atoms or molecules form ions.
#Tutorial 05      Video Runtime: 04:21      Solution: PC|Mac :: Android|iOS
In this lesson, we will give you some general rules to help determine whether two atoms are likely to form a bond.
#02-06-00      Video Runtime: 02:35      Solution: PC|Mac :: Android|iOS

(a) When they form ionic compounds, which elements in the 3rd row of the periodic table are expected to lose electrons? Which ones should gain electrons?

(b) If the following binary compounds are formed from elements in the 3rd row of the periodic table, determine whether that compound should be ionic or covalent: S with Cl, Mg with S, Al with P.
08Naming compounds
#02-08-00      Video Runtime: 04:19      Solution: PC|Mac :: Android|iOS

(a) Provide systematic names of the following compounds: AlCl3 , FeSO3, N2O5.

(b) Provide formula for the following compounds:cesium hydrogen carbonate, copper (I) sulfate, mercury (I) chloride.
03Stoichiometry
01Atomic theory and stoichiometry
#Tutorial 01      Video Runtime: 03:31      Solution: PC|Mac :: Android|iOS
The concept of atoms is central to all of chemistry. A proper understanding of atoms is particularly key to mastering stoichiometry. In this lesson, we will look at the implications of atoms on stoichiometry in a different way.
03Molar mass
#03-03-00      Video Runtime: 03:55      Solution: PC|Mac :: Android|iOS

(a) Calculate the molar mass of calcium phosphate, Ca3(PO4)2.

(b) Calculate the mass of Ca, P and O in 100.0 g of calcium phosphate and the number of atoms of each.
04Mass composition of compoundss
#03-04-00      Video Runtime: 03:05      Solution: PC|Mac :: Android|iOS
Calculate the mass percentages of Al, S and O in aluminum sulfate.
05Empirical formula
#03-05-00      Video Runtime: 04:54      Solution: PC|Mac :: Android|iOS

(a) A certain compound has the following mass composition: 5.15% hydrogen, 49.48% carbon, 28.87% nitrogen and 16.49% oxygen. Determine its empirical formula.

(b) This compound has a molar mass of approximately 195 g/mol. What is its molecular formula?
07Balancing chemical equations
#03-07-00      Video Runtime: 05:04      Solution: PC|Mac :: Android|iOS

Balance the following reactions:

(a) NH3 + O2 → NO + H2O

(b) The compound C8H10N4O2 is burned in oxygen to produce CO2, H2O and N2.

(c) An acidic solution of dichromate ions reacts with metallic aluminum to form chromium (III) oxide, aluminum ions and water.
08Stoichiometry calculations
#Tutorial 02      Video Runtime: 05:22      Solution: PC|Mac :: Android|iOS
This lesson will explain the basic concept of what a limiting reagent is and its role in a stoichiometry calculation.
#Tutorial 03      Video Runtime: 03:04      Solution: PC|Mac :: Android|iOS
This lesson explains how to determine the number of moles for a stoichiometry calculation if the reaction involves solids, liquids, solutions or gases.
#03-08-00      Video Runtime: 03:07      Solution: PC|Mac :: Android|iOS

Metallic lead can be produced from lead (IV) oxide according to the following reaction:

PbO2(s) + 2CO(g) → Pb(s) + 2CO2(g)

What is the mass of lead (IV) oxide required to produced 1000. kg of Pb? How many kg of CO2 gas is produced in this process?
#03-08-01      Video Runtime: 06:36      Solution: PC|Mac :: Android|iOS
Mn2O3 reacts with S to form MnO and SO2. If 5.674 g of Mn2O3 is reacted with 0.835 g of S, which one is the limiting reagent? What mass of MnO and SO2 is produced?
#03-08-02      Video Runtime: 04:29      Solution: PC|Mac :: Android|iOS

For the following reaction:

Fe(s) + 2 Cr(s) + 4 CO(g) → FeCr2O4(s) + 4 C(s)

if 10.00 g of each of Fe, Cr and CO are reacted with each other, what is the theoretical yield of FeCr2O4 by mass?
04Solution Stoichiometry
03Concentrations
#Tutorial 03      Video Runtime: 03:04      Solution: PC|Mac :: Android|iOS
This lesson explains how to determine the number of moles for a stoichiometry calculation if the reaction involves solids, liquids, solutions or gases.
#04-03-00      Video Runtime: 01:04      Solution: PC|Mac :: Android|iOS
A 0.235 M solution of NaCl is to be produced by diluting a 1.87 M NaCl stock solution. What is the volume of 1.87 M NaCl needed to produce 573. mL of 0.235 M NaCl?
#04-03-01      Video Runtime: 03:01      Solution: PC|Mac :: Android|iOS

Calculate the final chloride ion concentration in the following:

(a) 25.64 mL of 1.35 M calcium chloride diluted to a final volume of 214.0 mL.

(b) 125. mL of 0.562 M calcium chloride is mixed with 75.0 mL of 0.825 M NaCl.
04Common reactions in solutions
#Tutorial 11      Video Runtime: 03:38      Solution: PC|Mac :: Android|iOS
This lesson discusses the most common types of reactions occurring in solutions.
05Precipitation reactions
#04-05-00      Video Runtime: 06:30      Solution: PC|Mac :: Android|iOS

68.5 mL of 0.430 M potassium sulfate is mixed with 56.3 mL of 0.550 M barium nitrate.

(a) What is the precipitate?

(b) Write down the net ionic equation.

(c) Calculate the mass of the precipitate produced?

(d) Calculate the concentration of all ions in the final solution.
08Acid-base reactions
#04-08-00      Video Runtime: 02:02      Solution: PC|Mac :: Android|iOS
52.45 mL of a sulfuric acid solution with an unknown concentration is titrated with 0.4325 M NaOH. 123.85 mL of NaOH is needed to reach the endpoint. Calculate the original concentration of the sulfuric acid solution.
09Oxidation-reduction reactions
#04-09-00      Video Runtime: 02:59      Solution: PC|Mac :: Android|iOS

(a) Determine the oxidation state of all elements in the following (unbalanced) reaction: HNO3(aq) + Fe(s) → NO(g) + FeNO3(aq)

(b) Which reactant is the oxidizing agent? Which one is the reducing agent?
10Balancing redox equations
#Tutorial 06      Video Runtime: 04:29      Solution: PC|Mac :: Android|iOS
This lesson explains how to use the half-reaction method to balance any redox equation.
#04-10-00      Video Runtime: 02:42      Solution: PC|Mac :: Android|iOS

Balance the following redox equation:

Co3+ + Hg → Co2+ + Hg22+
#04-10-01      Video Runtime: 03:33      Solution: PC|Mac :: Android|iOS

(a) Balance the following redox equation in acidic solution:

Cu + HNO3 (aq) → Cu2+ (aq) + NO (g)
#04-10-02      Video Runtime: 06:25      Solution: PC|Mac :: Android|iOS

(a) Balance the following redox equation in acidic solution:

C2H5OH (aq) + MnO4- (aq) → MnO2 (s) + CO2 (g)

(b) Balance the same reaction in basic solution.
05Gases and Reactions Involving Gases
01Pressure
#05-01-00      Video Runtime: 01:26      Solution: PC|Mac :: Android|iOS
At room temperature, the vapor pressure of water is approximately 25 torr. Convert this to atm and psi.
02Gas laws
#05-02-00      Video Runtime: 02:47      Solution: PC|Mac :: Android|iOS

A gas starts at 742. torr and 25.0 oC with an initial volume of 3.27 L.

(a) It is first heated to 65.5 oC at constant pressure. Calculate its new volume.

(b) The gas is then compressed at constant temperature back to 1.85 L. Calculate its new pressure.
04The ideal gas law
#05-04-00      Video Runtime: 02:35      Solution: PC|Mac :: Android|iOS
Calculate the density of air at STP.
#05-04-01      Video Runtime: 02:07      Solution: PC|Mac :: Android|iOS
At high temperature, solid ammonium hydroxide (NH4OH) decomposes to water vapor and NH3 gas. 12.6 g of ammonium hydroxide is placed in an evacuated 1L-flask and then heated to 250. oC. The ammonium hydroxide is allowed to decompose completely. Determine the final pressure of the gas mixture inside the flask.
#05-04-02      Video Runtime: 04:32      Solution: PC|Mac :: Android|iOS
Propene gas (C3H6) burns in oxygen gas to form carbon dioxide and water vapor. A sample of propene gas having a volume of 2.35 L at 25 oC and 1.50 atm is mixed with 6.45 L of O2 gas at 45 oC and 2.00 atm and the mixture is ignited. Determine the mass of carbon dioxide produced.
05Partial pressures
#05-05-00      Video Runtime: 02:38      Solution: PC|Mac :: Android|iOS
The reaction between nitrogen gas and hydrogen gas makes NH3 gas. A mixture of N2 and H2, each with a partial pressure of 0.500 atm is reacted to completion at a constant temperature of 635 K inside a fixed-size vessel. Determine the total pressure of the product.
06Kinetic theory of gases
#05-06-00      Video Runtime: 03:41      Solution: PC|Mac :: Android|iOS

(a) Calculate the root mean square velocities of O2 and H2 gas at room temperature.

(b) An equimolar mixture of O2 and H gas are held in a Knudson cell and allowed to effuse through a small pinhole. Which gas escapes faster? What are their relative rates of effusion?
06Thermochemistry and the First Law of Thermodynamics
01Energy, heat and work
#Tutorial 10      Video Runtime: 06:23      Solution: PC|Mac :: Android|iOS
This lesson explains the basic concepts of thermochemistry and the 1st Law of Thermodynamics.
#06-01-00      Video Runtime: 02:30      Solution: PC|Mac :: Android|iOS
586. J of energy is used to heat a gas from 298. K to 345. K. The gas expands from 5.64 L to 13.50 L against an external pressure of 1.00 atm. Calculate the total change in internal energy of the gas.
02Enthalpy and calorimetry
#06-02-00      Video Runtime: 01:51      Solution: PC|Mac :: Android|iOS
Calculate the final temperature when a 40.0 g sample of aluminum (specific heat capacity 0.890 J/K/g) at 65.0 oC is dropped into 100. g of water (specific heat capacity 4.18 J/K/g) at 20.0 oC.
#06-02-01      Video Runtime: 03:08      Solution: PC|Mac :: Android|iOS

When a 4.25-g sample of solid ammonium nitrate dissolves in 60.0 g of water in a coffee-cup calorimeter, the temperature decreases from 22.06 oC to 16.9 oC.  Calculate DH (in kJ/mol NH4OH) for the solution process:

NH4OH (s) → NH4+ (aq) + OH- (aq)

Assume that the specific heat capacity of the solution is 4.22 J/g/K.
03Hess's law
#06-03-00      Video Runtime: 02:17      Solution: PC|Mac :: Android|iOS

Given the following data:

N2 (g) + O2 (g) → 2 NO (g) DH = +180.7 kJ

2 NO (g) + O2 (g) → 2 NO2 (g) DH = -113.1 kJ

2 N2O (g) → 2 N2 (g) + O2 (g) DH = -163.2 kJ

calculate DH for the reaction:

NO2 (g) + N2O (g) → 3 NO (g)
04Enthalpy of reactions
#06-04-00      Video Runtime: 02:02      Solution: PC|Mac :: Android|iOS
Solid glucose (C6H12O6) burns in oxygen gas (O2) to form CO2 gas and water vapor. Use standard enthalpies of formation to calculate the standard molar enthalpy change of this reaction.
07Electronic Structure of the Atom
02Light and waves
#07-02-00      Video Runtime: 01:28      Solution: PC|Mac :: Android|iOS

Lasers can be made with different materials.

(a) CO2 lasers produce light with a 10.6 micron wavelength. What is the frequency of this light? Is it in the visible, IR, or UV?

(b) An Argon ion laser produces light with a 514 nm wavelength. What is its frequency? Is it in the visible, IR or UV?
03Wave nature of matter
#07-03-00      Video Runtime: 01:37      Solution: PC|Mac :: Android|iOS

What is the de Broglie wavelength of an electron traveling at 1% the speed of light?

04The hydrogen atom and electron energy levels
#07-04-00      Video Runtime: 03:12      Solution: PC|Mac :: Android|iOS
In an excited hydrogen atom, an electron falls from the 6f orbital to the 2p orbital. Calculate the wavelength of the resulting emission.
06One-electron atoms
#07-06-00      Video Runtime: 01:25      Solution: PC|Mac :: Android|iOS
Is the following set of quantum numbers allowed: n=3, l=2, ml=2?
#07-06-01      Video Runtime: 01:51      Solution: PC|Mac :: Android|iOS
How many different orbitals are there in the n=8 shell?
08Many-electron atoms
#07-08-00      Video Runtime: 01:40      Solution: PC|Mac :: Android|iOS
What is the electronic configuration of Cu?
#07-08-01      Video Runtime: 01:47      Solution: PC|Mac :: Android|iOS
What is the electronic configuration of Ir?
#07-08-02      Video Runtime: 01:58      Solution: PC|Mac :: Android|iOS
Predict the electronic configuration of the as yet undiscovered element with atomic number 116.
09Periodic trends
#07-09-00      Video Runtime: 02:20      Solution: PC|Mac :: Android|iOS

Of the atoms P, S, Ar, Se, Sb and Sn:

(a) which one has the smallest size?

(b) which one has the lowest ionization energy?

(c) which one has the highest electron affinity?
08Bonding, Lewis Structures and VSEPR
01Ionic bonds
#08-01-00      Video Runtime: 01:09      Solution: PC|Mac :: Android|iOS
MgO has about the same bond distance as NaF. Which compound forms a stronger bond?
02Electronic configurations of ions
#08-02-00      Video Runtime: 01:24      Solution: PC|Mac :: Android|iOS
What is the electronic configuration of: Sr2+, Fe2+ and Fe3+?
03Covalent bonds and bond polarity
#08-03-00      Video Runtime: 02:36      Solution: PC|Mac :: Android|iOS
Which of the following molecules is expected to have the highest bond polarity: N2, CO, KF, ICl?
08Covalent bond energies
#08-08-00      Video Runtime: 02:30      Solution: PC|Mac :: Android|iOS
Acetylene (C2H2) is a gas often used in welding. Use average bond enthalpies to estimate the heat delivered when 1 mole of acetylene is burned in air. (The C-C bond in acetylene is a triple bond.)
10Lewis structures
#Tutorial 08      Video Runtime: 04:11      Solution: PC|Mac :: Android|iOS
This lesson shows you how to easily determine the Lewis structure of a molecule.
#Tutorial 09      Video Runtime: 05:24      Solution: PC|Mac :: Android|iOS
This lesson shows you how to determine the Lewis structure of a molecule and use it to assign formal charges to all atoms in the molecule.
#08-10-00      Video Runtime: 15:01      Solution: PC|Mac :: Android|iOS
Draw Lewis structures and assign formal charges for the following molecules: PH3, CH2O, POCl3, SF2.
#08-10-01      Video Runtime: 13:44      Solution: PC|Mac :: Android|iOS
Draw Lewis structures and assign formal charges for the following molecules: ClO2-, NO2-, SF4.
11Exceptions to the octet rule
#08-11-00      Video Runtime: 06:34      Solution: PC|Mac :: Android|iOS
Which of the following violate(s) the octet rule: O3, PCl5, I3-, PO43-, XeF4.
12Resonance structures
#08-12-00      Video Runtime: 08:09      Solution: PC|Mac :: Android|iOS
In each of the molecules: SO, SO2, SO3, SO32-, all S-O bonds are equivalent. Use resonance structures to determine the bond order of each S-O bond in each molecule. (S is the center atom in all molecules.)
13VSEPR
#Tutorial 07      Video Runtime: 03:20      Solution: PC|Mac :: Android|iOS
This lesson shows you how to do VSEPR easily, without having to first draw the Lewis structure. This method will work for all molecules where there is one center atom and all the other atoms are bonded to it.
#08-13-00      Video Runtime: 10:20      Solution: PC|Mac :: Android|iOS
Use VSEPR to determine the geometry of the following molecules: XeF4, SO2, SO3, PF3. (In each molecule, the first atom is the center atom.)
#08-13-01      Video Runtime: 07:31      Solution: PC|Mac :: Android|iOS
Use VSEPR to determine the geometry of the following molecules: PCl5, I3-,SF6. (In each molecule, the first atom is the center atom.)
09Molecular Orbitals
01Hybridized atomic orbitals
#09-01-00      Video Runtime: 01:50      Solution: PC|Mac :: Android|iOS
What is the hybridization on the carbon atoms in the following molecules: CH4, C2H6, C2H4, C2H2, CO, CO2, CO32-.
03Molecular orbital theory of diatomic molecules
#09-03-00      Video Runtime: 03:35      Solution: PC|Mac :: Android|iOS
Draw the MO diagram for the following diatomic molecules: C2, O2 , and N2. For each, determine its bond order and whether the molecule is paramagnetic.
#09-03-01      Video Runtime: 01:40      Solution: PC|Mac :: Android|iOS
NO is one of the molecules that do not obey the octet rule, and its bonding cannot be fully explained by Lewis structure. But MO theory has no such problem. What is the correct bond order of this molecule?
12Kinetics
01Definition of reaction rates
#Tutorial 12      Video Runtime: 05:17      Solution: PC|Mac :: Android|iOS
This lesson explains the basic concepts of reaction kinetics and differential and integrated laws of first and second order reactions.
#12-01-00      Video Runtime: 03:47      Solution: PC|Mac :: Android|iOS

For the reaction:

2 N2O5(g) --> 4 NO2(g) + O2(g)

(a) How is the rate of appearance of NO2 (d[NO2]/dt) related to the rate of disappearance of N2O5 and the rate of appearance of O2?

(b) If this reaction is second-order in N2O5, write down the rate law. What is the correct unit for the rate constant?
03Method of intitial rates
#12-03-00      Video Runtime: 05:04      Solution: PC|Mac :: Android|iOS

For the reaction:

A + 2 B + 4 C --> products

(a) Use the following initial rate data to determine the rate law.

 Expt # [A]0 (M) [B]0 (M) [C]0 (M) Initial Rate (M/s) 1 0.01 0.01 0.005 1.15 x 10-2 2 0.01 0.01 0.01 4.60 x 10-2 3 0.01 0.02 0.01 1.15 x 10-2 4 0.02 0.01 0.005 2.30 x 10-2
(b) What is the value of the rate constant?
04Integrated rate laws
#12-04-00      Video Runtime: 04:43      Solution: PC|Mac :: Android|iOS

For the reaction:

B(g) --> products

a certain amount of B was placed in a sealed container and allowed to react.

(a) The following concentration data were obtained at different times.

 Time (s) [B] (M) 1000s 0.00625 2800s 0.00370 5200s 0.00241

What is the order of the reaction in B?

(b) What is the value of the rate constant?

(c) What is the initial concentration of B at 0s?
06Reaction mechanicsms
#Tutorial 13      Video Runtime: 05:23      Solution: PC|Mac :: Android|iOS
This lesson explains how to use reaction mechanisms to derive the overal rate law and discusses the role of reaction intermediates and catalysts in a mechanism.
#12-06-00      Video Runtime: 03:59      Solution: PC|Mac :: Android|iOS

(a) Write down the overall reaction for the following mechanism:

NO2(g) + F2(g) --> NO2F + F (fast equilibrium)

F + NO2 --> NO2F (slow)

(b) Which species is (are) the intermediates? Is any species acting as a catalyst?

(c) Determine the overall rate law.
07Temperature dependence of rates
#12-07-00      Video Runtime: 04:18      Solution: PC|Mac :: Android|iOS

(a) A certain chemical reactions is twice as fast at 60 oC compared to 30 oC, calculate the activation energy of this reaction.

(b) The reaction is exothermic with a DH = -46 kJ/mol. Sketch the energy profile for this reaction. What is the activation energy for the reverse reaction?
13Chemical Equilibrium
01The basic concept of equilibrium
#Tutorial 14      Video Runtime: 06:59      Solution: PC|Mac :: Android|iOS
This lesson discusses the basic ideas of chemical equilibrium and how to set up an ICE calculation.
03Equilibrium expressions involving pressures
#13-03-00      Video Runtime: 04:07      Solution: PC|Mac :: Android|iOS

(a) Write down the equilibrium expression for the following reaction:

2 N2O5(g) --> 4 NO2(g) + O2(g)

(b) If the equilibrium constant Kp for this reaction is 0.00352 at 330 K, what is the value of the equilibrium constant Kc at this temperature?

(c) What is the equilibrium constant Kc for the reverse reaction?
05The reaction quotient and extent of reaction
#Tutorial 15      Video Runtime: 08:08      Solution: PC|Mac :: Android|iOS
This lesson discusses the reaction quotient and gives you additional tools for handling typical ICE calculations.
#13-05-00      Video Runtime: 09:26      Solution: PC|Mac :: Android|iOS

For the reaction:

H2(g) + F2(g) --> 2HF(g)

the equilibrium constant is 12.1.

(a) If initially 0.500 mole of H2, 0.300 mole of F2 and 1.000 mole of HF were mixed in a 1.50-L flask, which way will the reaction move to reach equilibrium?

(b) Calculate the equilibrium concentrations of all three species.
06Equilibrium calculations
#13-06-00      Video Runtime: 04:32      Solution: PC|Mac :: Android|iOS

The equilibrium constant for the reaction:

2 N2O5(g) --> 4 NO2(g) + O2(g)

is 1.3 x 10-6. If N2O5 with an initial concentration of 1.000 M is allowed to react to equilibrium, calculate the equilibrium concentrations of all three species.
07Le Chatelier's principle
#13-07-00      Video Runtime: 02:15      Solution: PC|Mac :: Android|iOS

For the following reaction:

UO2(s) + 4HF(g) <=> UF4(g) + 2H2O(l)        DH = +23.2 kJ/mol

how will the following changes affect the equilibrium?

 (a) increasing the temperature (b) adding more HF (c) removing H2O (d) increasing the volume (e) adding UO2 (f) adding H2 gas
14Acid Base Equilibria
01Introduction to acid-base reactions
#Tutorial 16      Video Runtime: 09:15      Solution: PC|Mac :: Android|iOS
This lesson describes the key to understanding acid base equilibrium, pH and acid and base strengths.
02Acid and base strengths
#14-02-00      Video Runtime: 02:46      Solution: PC|Mac :: Android|iOS

Using the table of Ka values, order the following bases by their relative strength:

H2O, F-, Cl-, NO2- and CN-.
03pH and pOH
#14-03-00      Video Runtime: 01:42      Solution: PC|Mac :: Android|iOS

(a) What is the H3O+ and OH- concentration in a pH 4.550 buffer solution?

(b) What is the pOH?
04pH of strong acids
#14-04-00      Video Runtime: 00:45      Solution: PC|Mac :: Android|iOS
Calculate the pH of a 0.0475 M solution of HCl.
05pH of weak acids
#14-05-00      Video Runtime: 04:42      Solution: PC|Mac :: Android|iOS

(a) Calculate the pH of a 0.0475 M solution of HNO2.

(b) Calculate the percent dissociation.
#14-05-01      Video Runtime: 04:33      Solution: PC|Mac :: Android|iOS

(a) Calculate the pH of a solution containing 0.0475 M HNO2 and 0.100 M NH4Cl.

(b) Calculate the concentrations of all dissolved species in this solution.
#14-05-02      Video Runtime: 03:42      Solution: PC|Mac :: Android|iOS
Calculate the pH of a 1.00 M solution of HCN.
06pH of basic solutions
#14-06-00      Video Runtime: 04:15      Solution: PC|Mac :: Android|iOS

The Ka of a certain monoprotic acid HX is 3.87×10-6.

(a) Calculate the Kb of its conjugate base X-.

(b) Calculate the pH of a 0.0475 M solution of NaX.
07Polyprotic acids
#14-07-00      Video Runtime: 06:40      Solution: PC|Mac :: Android|iOS

Calculate the concentrations of all dissolved species in a 1.00 M solution of oxalic acid.

(Oxalic acid is a diprotic acid: Ka1 = 6.5x10-2, Ka2 = 6.1x10-5.)
08Acid-base properties of salts
#14-08-00      Video Runtime: 04:34      Solution: PC|Mac :: Android|iOS
Determine whether the following will produce an acidic, basic or neutral solutions when dissolved in water: KNO2, NaCH3COO, K2O, NaCl, NH4Cl,NH4NO2.
15Buffers, Solubility and Complex Ion Equilibria
02Buffers
#15-02-00      Video Runtime: 06:41      Solution: PC|Mac :: Android|iOS

(a) How much NaOH has to be dissolved in 500. mL of 0.400 M acetic acid to form a pH = 4.500 buffer?

(b) If HCl gas is dissolved in this buffer, how will the pH change?

(c) How many moles of HCl can be dissolved in this buffer before the pH changes by 0.500?
04Acid-base titrations
#15-04-00      Video Runtime: 10:17      Solution: PC|Mac :: Android|iOS

50.00 mL of a 0.100 M solution of methyl amine (CH3NH2) is titrated with 0.150 M HNO3.

(a) Calculate the volume of HNO3 needed to reach the equivalence point.

(b) Calculate the pH at the equivalence point.

(c) Calculate the pH after 10.0 mL of HNO3 has been added.

(d) Calculate the pH after 50.0 mL of HNO3 has been added.
#15-04-01      Video Runtime: 06:32      Solution: PC|Mac :: Android|iOS

60.0 mL of a weak monoprotic acid of an unknown concentration is titrated with 0.100 M NaOH. 86.3 mL of NaOH is needed to reach the equivalence point.

(a) What is the concentration of the weak acid?

(b) The pH at the half-equivalence point is 5.87. Calculate the Ka of this unknown acid?

(c) From your answers to (a) and (b), calculate the pH at the equivalence point.
06Solubility equilibria
#15-06-00      Video Runtime: 06:17      Solution: PC|Mac :: Android|iOS

The Ksp for CaF2 is 4.0 x 10-11.

(a) Calculate the solubility of CaF2 in pure water.

(b) Calculate the solubility of CaF2 in a 0.100 M KF solution.

(c) When 100.0 mL of 0.100 M Ca(NO3)2 is mixed with 100.0 mL of 0.0100 M KF, will a precipitate form?
08Complex ion equilibria
#15-08-00      Video Runtime: 03:20      Solution: PC|Mac :: Android|iOS
Calculate the concentrations of Hg2+, I- and of the complex [HgI4]2- in a solution containing 1.00 M mercury (II) nitrate and 1.00 M potassium iodide. The equilibrium constant for the formation of the complex [HgI4]2- is 1.0 x 1030.
16Entropy and the Second Law of Thermodynamics
04Free energy
#16-04-00      Video Runtime: 07:10      Solution: PC|Mac :: Android|iOS

(a) Calculate the boiling point of methyl alcohol (CH3OH).

(b) Calculate the vapor pressure of methyl alcohol at 25 oC.
06Free energy change in chemical reactions
#16-06-00      Video Runtime: 10:09      Solution: PC|Mac :: Android|iOS

For the reaction:

2SO2(g) + O2(g) --> 2SO3(g)

(a) Calculate DH0, DS0, and DG0 .

(b) Explain the sign of DS0.

(c) Is this reaction spontaneous at standard condition?

(d) Calculate the equilibrium constant of this reaction at 298 K.

(e) Calculate the equilibrium constant of this reaction at 1000 K.

(f) The following mixture of the three gases are prepared in a 1.000-L flask at 1000 K: 0.300 mole of SO2, 0.200 mole of O2 and 2.50 mole of SO3. In which direction is the reaction spontaneous?
08Free energy and equilibrium
#16-08-00      Video Runtime: 07:10      Solution: PC|Mac :: Android|iOS

(a) Calculate the boiling point of methyl alcohol (CH3OH).

(b) Calculate the vapor pressure of methyl alcohol at 25 oC.
17Electrochemistry
03Cell potentials, electrical work and free energy
#17-03-00      Video Runtime: 07:56      Solution: PC|Mac :: Android|iOS

Consider the following (at standard conditions):

Na+, Cl-, Ag+, Ag, Zn2+, Zn, Pb, Fe, Fe2+, Mg, Mg2+, Sn

(a) Which ones can act as oxidizing agents? Which one is the strongest oxidizing agent?

(b) Out of the list in (a), which species can be reduced by Al?

(c) Which ones can act as reducing agents? Which one is the strongest reducing agent?

(d) Out of the list in (c), which species can be oxidized by Fe3+?
04Concentration dependence of cell potentials
#17-04-00      Video Runtime: 05:58      Solution: PC|Mac :: Android|iOS

A galvanic cell is based on the following redox reaction:

Zn + Cu2+ --> products

(a) Write down the products of this reaction.

(b) Calculate the standard cell potential.

(c) Make a sketch of this cell and label all the relevant parts.

(d) Calculate the cell potential if everything is at standard condition except for [Cu2+] = 1.00 x 10-4 M.

(e) Ammonia forms a complex with Cu2+. How will the addition of ammonia to the copper half-cell affect the cell potential?
#17-04-01      Video Runtime: 04:10      Solution: PC|Mac :: Android|iOS

A concentration cell is constructed using two Ag/Ag+ half-cells with the same volume.

(a) The concentration of Ag+ in one cell is 1.00 M and 0.100 M in the other. Calculate the cell potential.

(b) When the reaction proceeds, what happens to the concentrations in the two half-cells?

(c) Which side is the cathode?

(d) When will the reaction stop? What is the concentration in each half-cell when the reaction stops, assuming that the two half-cells have the same volume?
#17-04-02      Video Runtime: 03:05      Solution: PC|Mac :: Android|iOS

Use the following standard reduction potentials to calculate the Ksp of mercury (I) chloride.

Hg2Cl2 + 2e- --> 2Hg + 2Cl-       +0.34 V

Hg22+ + 2e- --> 2Hg       +0.80 V
07Electrolytic cells
#17-07-00      Video Runtime: 00:46      Solution: PC|Mac :: Android|iOS
A solution in an electrolytic cell contains Cu2+, Ag+ and Au3+. When a current is applied to the cell, which metal will be plated out first? Second? And last?
#17-07-01      Video Runtime: 01:03      Solution: PC|Mac :: Android|iOS
An electrolysis is used to plate gold from a Au3+ solution at a constant current of 15 A onto a metal surface. What is the mass of gold plated out in one hour?
20Coordination Chemistry
03Naming coordination compounds
#20-03-00      Video Runtime: 05:05      Solution: PC|Mac :: Android|iOS

Give systematic names for the following compounds:

(a) [Co(NH3)5Cl]Cl2

(b) K3[Fe(CN)6]

(c) [Fe(en)2(NO2)2]2SO4

Provide chemical formula for the following:

(a) tetracarbonyldifluoroiron (III) nitrate

(b) bis(ethylenediamine)diamminecolbalt (III) tetrachloroplatinate (II)
04Isomerism
#20-04-00      Video Runtime: 02:22      Solution: PC|Mac :: Android|iOS

Draw all distinct isomers of the following complexes:(a) [Co(en)3]2+

(a) [Co(CO)2(en)2]2+
#20-04-01      Video Runtime: 01:40      Solution: PC|Mac :: Android|iOS
How many coordination isomers does the compound Fe(CO)4BrClI have? (In this compound, Fe is 6-coordinate.)
06Crystal field theory
#20-06-00      Video Runtime: 03:56      Solution: PC|Mac :: Android|iOS

Explain the following observations by using the crystal field theory and the proper electronic configurations of the d-orbitals in these complexes:

(a) Fe(CN)64- is diamagnetic but Fe(H2O)62+ is paramagnetic.

(b) Co3+ forms an octahedral complex with an unknown monodentate ligand L. It has an orange color. Is the ground-state complex likely to be paramagnetic or diamagnetic? Why?
21Nuclear Chemistry
#21-01-00      Video Runtime: 02:26      Solution: PC|Mac :: Android|iOS

(a) 210Po undergoes an a-particle decay. What nuclide does this produce?

(b) The products of a nuclear decay reaction is a b-particle and 131Xe. What is the original nuclide.
#21-04-00      Video Runtime: 01:31      Solution: PC|Mac :: Android|iOS
The 14C:12C ratio in a piece of cloth found in an archeological site has 82.3% its present-day value. Carbon-14 has a half life of 5730 years. Calculate the age of this material.
05Thermodynamic stability of the nucleus
#21-05-00      Video Runtime: 07:00      Solution: PC|Mac :: Android|iOS

(a) Calculate the nuclear binding energy per nucleon for the 79Kr nuclide (the atomic mass of 79Kr is 78.920083 amu).

(b) A nuclear reaction that has been proposed as a potential source of energy is the fusion of the nuclides of hydrogen (1H, atomic mass 1.007825035 amu) and deuterium (2H, atomic mass 2.014101779 amu), producing the nuclide of a helium-3 (3He, atomic mass 3.01602931 amu). Calculate the energy of this reaction per gram of 3He produced?

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