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Chem Quizzes/Tests

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A researcher needs to prepare a pH 5 buffer. What solutions would be best?

0.20 M propanoic acid (Ka = 1.3 ´ 10-5) + 0.10 M sodium hydroxide

Do this without a calculator: The number of moles of Al(NO3)3 that must be added to water to form 2.00 L of 0.30 M NO31- ions is:

0.20 mol

What mass of Ti(s) may be deposited from an aqueous TiCl2 solution if a current of 2.50 A is applied to the solution for 365 s? (e°red(Ti2+/Ti) = -1.63 V, F = 96485 C/mol)

0.226 g

Which of the following mixtures would NOT be described as a buffer solution? 0.20 M NaOH and 0.40 M CH3COOH 0.15 M NH4Cl and 0.25 M NH3 0.25 M HNO3 and 0.15 M KNO3 0.25 M HNO2 and 0.15 M KNO2

0.25 M HNO3 and 0.15 M KNO3

Refer to the galvanic cell below (the contents of each half-cell are written beneath each compartment): mc002-1.jpg 0.10 M MnO4- 0.40 M Cr3+ 0.20 M Mn2+ 0.30 M Cr2O72- 0.010 M H+ 0.010 M H+ The standard reduction potentials are as follows: MnO4- + 8H+ + 5e- ® Mn2+ + 4H2O, e° = 1.51 V Cr2O72- + 14H+ + 6e- ® 2Cr3+ + 7H2O, e° = 1.33 V What is the cell potential at 25°C as read on the digital voltmeter?

0.26 V

87Sr is a radiotracer used in studying bones...

0.3%

For the reaction given below, 2.00 moles of A and 3.00 moles of B are placed in a 6.00-L container.

0.325 mol/L

Determine the Kp for the following reaction if at equilibrium half of the initial SO2 reacted to form 2.00 atm of SO3. The initial partial pressures of SO2 and O2 were equal. (Do without a calculator)

0.333 atm

A cell is set up with copper and lead electrodes in contact with CuSO4(aq) and Pb(NO3)2(aq), respectively, at 25°C. The standard reduction potentials are: Pb2+ + 2e- ® Pb e° = -0.13 V Cu2+ + 2e- ® Cu e° = +0.34 V If the Pb2+ and Cu2+ are each 1.0 M, the potential of the cell, in volts, is:

0.47 V

A student uses acetic acid to titrate a solution of copper(I) hydroxide to deteremine the concentration of the copper(I) hydroxide. If 30.0 mL of 0.250 M acetic acid is needed to neutralize 15.0 mL copper(I) hydroxide, what is the molarity of the copper(I) hydroxide? Do this without a calculator.

0.500 M

If 103.5 g of XeF4 is reacted with excess water, how many moles of hydrofluoric acid are produced? Molar mass of XeF4 is 207 g/mol. Do this without a calculator.

0.500 mol

The reduction potentials for Au3+ and Ni2+ are as follows: Au3+ + 3e-→ Au, e° = +1.50 V Ni2+ + 2e-→ Ni, e° = -0.229 V Calculate ΔG° (at 25°C) for the reaction: 2Au3+ + 2Ni→ 3Ni2+ + 2Au

-1.00 x 10^3 kj

What is the oxidation state of Hg in Hg2Cl2?

what is E cell for the voltaic cell using the 2 half-reactions at 25

+2.46 V

The oxidation number of N in Ca(NO3)2 is

Consider the freezing of liquid water at -10°C. For this process what are the signs for DH, DS, and DG? DH DS DG

- - -

What would be the charge on an ion formed from this atom? (273, 26.0, 20)

-1

What is the enthalpy change for the following reaction under standard conditions? Solve without a calculator. mc003-1.jpg

-1076 kJ

Solve without using a calculator. Calculate the concentration of chloride ions when 200.0 mL of 1.00 M sodium chloride is mixed with 300.0 mL of 1.00 M magnesium chloride.

1.60 M

It is observed that 7.50 mmol of BaF2 will dissolve in 1.0 L of water. Use these data to calculate the value of Ksp for barium fluoride.

1.7 x 10-6

Using the following data to calculate Ksp for PbSO4. e° PbO2 + 4H+ + SO42- + 2e- → PbSO4(s) + 2H2O +1.69 PbO2 + 4H+ + 2e- → Pb2+ + 2H2O +1.46

1.7 x 10-8

A 20.0 g sample of a hydrated compound is placed into a crucible and heated. The data table for this laboratory investigation is shown below. What is the mass of the water of hydration in the hydrate?

1.7402 g

A solution of 8.01 M formic acid (HCOOH) is 0.47% ionized. What is the Ka value of formic acid?

1.8 x 10-4

The standard enthalpy of formation for nitrogen dioxide is the enthalpy change of the reaction

1/2N2

If, at a given temperature, the equilibrium constant for the reaction H2(g) + Cl2(g) mc011-1.jpg 2HCl(g) is Kp, then the equilibrium constant for the reaction HCl(g) mc011-1.jpg mc011-2.jpgH2(g) + mc011-3.jpgCl2 (g) can be represented as:

1/sqKp

How many electrons are transferred in the following reaction when it is balanced in acidic solution? SO32-(aq) + MnO4-(aq) ® SO42-(aq) + Mn2+(aq)

The total number of lone pairs in PCl3 is

Silver chloride is more soluble in ammonia than in water but both are thermodynamically unfavorable processes: AgCl(s) mc007-1.jpg Ag+(aq) + Cl-(aq) DG° = 55.9 kJ/mol AgCl(s) + 2NH3 mc007-2.jpg Ag(NH3)2+ + Cl- DG° = 14.6 kJ/mol The process in ammonia goes through three stages, of which 2 are thermodynamically favorable: Ag+ + NH3 mc007-3.jpg Ag(NH3)+ DG° = -19.0 kJ/mol Ag(NH3)+ + NH3 mc007-4.jpg Ag(NH3)2+ DG° = -22.3 kJ/mol In which of the following solutions would silver chloride be the most soluble (using consideration of Le Chatelier's principle)?

10.0 M NH3

Copper may be used for electroplating, with half-reaction of Cu2+ + 2e- = Cu. If a current of 10.0 A is applied to a Cu2+ colution for 60.0 minutes

10.0 x 3600. x (1/96,500) x (1/2.00) x 63.5

Which of the following will not produce a buffered solution? 50 mL of 0.2 M Na2CO3 and 5 mL of 1.0 M HCl 100 mL of 0.1 M Na2CO3 and 75 mL of 0.2 M HCl 100 mL of 0.1 M Na2CO3 and 50 mL of 0.1 M NaOH 100 mL of 0.1 M Na2CO3 and 50 mL of 0.1 M HCl

100 mL of 0.1 M Na2CO3 and 50 mL of 0.1 M NaOH

Predict the approximate bond angle around the carbon labeled 1 in the acetic acid molecule shown below.

109.5

If a sample of 27.0 g of aluminum metal is added to 333 mL of 3.0 M hydrochloric acid, the volume of hydrogen gas produced at standard temperature and pressure is: (Solve without using a calculator.)

11.2 L

Calculate the pH of a 2.3 x 10-3 M KOH solution.

11.36

The following reaction has a DG° value of 48.47 kJ/mol at 25°C. HB(aq) + H2O(l) mc030-1.jpg H3O+(aq) + B-(aq) Calculate the Ka for the acid HB.

3.19´ 10-9

What is e°cell for the following electrochemical equation? (e°red(Li+/Li) = -3.04 V, e°red(Cu2+/Cu) = 0.342 V) 2Li(s) + Cu2+(aq) ® 2Li+(aq) + Cu(s)

3.382 V

The [OH-] in a 0.87 M pyridine (C5H5N; Kb = 1.7 x 10-9) solution is

3.8 x 10-5 M

A 14.0-L cylinder contains the 5.60 g N2, 40.0 g Ar, and 6.40 g O2. What is the total pressure in atm at 27 degrees Celsium (R = the ideal gas constant.) Solve without using a calculator.

30 times R

One milliliter (1.00 mL) of acid taken from a lead storage battery is pipetted into a flask. Water and phenolphthalein indicator are added, and the solution is titrated with 0.55 M NaOH until a pink color appears; 12.0 mL are required. The number of grams of H2SO4 (formula weight = 98) present in one liter of the battery acid is:

323

The Mineral magnesite

33%

Phosphorus can be produced by reacting calcium phosphate, silicon dioxide, and carbon at high temperatures according to the following equation:

Solve without using a calculator. In a Bunsen burner, methane reacts with oxygen to produce carbon dioxide and water, as shown in the balanced equation below:

36 g

You fill a balloon with 2.50 moles of gas at 22°C at a pressure of 1.62 atm. What is the volume of the balloon?

37.4 L

Ag+ + e- = Ag E = 0.80V What is the balanced equation for the spontaneous reaction?

3Ag+ + Al = Al3+ + 3Ag

Calculate the enthalpy change for the following reaction given the information below. Al2(ClO3)3

3W + ½X - Y

The formation of an aluminum ion occurs when 3 electrons are removed. Which electron would require the most energy to remove?

3s because it experiences higher attractive forces

Which of the following correctly ranks the following species from smallest to largest ionic radius?

Ca2+, K1+, Cl1-, S2-

Using the lab data below, determine the rate law for the reaction of hydrogen gas with iodine vapor to form hydrogen iodide gas.

rate = k[[H2][I2]

What would happen to the cell emf if NH3 were added to the silver cell and Ag(NH3)21+ forms?

reduced

The following reaction is allowed to reach equilibrium is a glass bulb at a given temperature. 2 HgO(s) Û 2 Hg(l) + O2(g) DH = 43.4 kcal/mol. The mass of HgO in the bulb could be increased by:

reducing the volume of the bulb

The correct mathematical expression for finding the molar solubility (s) of barium chloride is:

s2 = Ksp

Which of these amino acids would you expect to exhibit the most hydrophilic behavior?

serine

You have a solution consisting of 0.10 M Cl- and 0.10 M CrO42-. You add 0.10 M silver nitrate dropwise to this solution. Given that the Ksp for Ag2CrO4 is 9.0 ´ 10-12, and that for AgCl is 1.6 ´ 10-10, which of the following will precipitate first?

silver chloride

Which of the following pairs of compounds will not form a homogeneous solution?

sodium cholride and mineral oil

What is the expected hybridization of the carbon labeled 2 in the acetic acid molecule shown below?

sp2

At constant pressure, the following reaction 2NO2(g) ® N2O4(g) is exothermic. The reaction (as written) is

spontaneous at low temperatures, but not high temperatures

For the reaction A + B ® C + D, DH° = +40 kJ and DS° = +50 J/K. Therefore, the reaction under standard conditions is

spontaneous at temperatures greater than 800 K

The average speed (vs. the energy) of the molecules of a gas is proportional to the

square root of the absolute temperature

Suppose that another gas D is added to the vessel in Figure 1, keeping the temperature and the volume constant. This is represented by Figure 2 above. What happens to the partial pressure of Gas B.

stays the same

The reaction H2(g) + I2(g) ® 2HI(g) has been considered to occur as a single elementary, bimolecular mechanism. However, in a recent laboratory investigation, the mixture was irradiated with light. When the wavelength used supplied the energy needed to dissociate the single bond, this caused the reaction rate to increase significantly. This would support the following mechanism:

step 2

Water has a higher capillary action than mercury due to

strong cohesive forces in water, which work with strong adhesive forces.

A 1.0 M solution of table salt (NaCl) is considered to be 1.0 M Na+ and 1.0 M Cl-. This means table salt is a

strong electrolyte

Name the element whose mass spectrum is shown above. germanium sulfur fermium selenium

sulfur

In a molecule in which the central atom exhibits sp3 hybrid orbitals, the electron pairs are directed toward the corners of a

tetrahedron

What is the best explanation for the decrease in first ionization energy moving from Be to B?

the electrons in the Be are located in the 2s subshell, which is closer to the nucleus and thurs harder to remove than th 2p electrons in B.

In deciding which of two acids is the stronger, one must know:

the equilibrium constant of each acid

The van der Waals equation, nRT = [P + a(n/V)2] (V - nb), incorporates corrections to the ideal gas law in order to account for the properties of real gases. One of the corrections accounts for

the finite volume of molecules

The formula for calcium bisulfate is

Ca(HSO4)2

The formula for calcium bisulfate is Ca2S Ca(SO4)2 Ca(HSO4)2 CaS2 Ca2HSO4

Ca(HSO4)2

if 200ml of .60 MgCl

0.20 M Mg ion & 0.40 M Cl ion

The [H3O+] of a 0.49 M solution of NH4Cl in H2O at 25°C is (Kb for NH3 = 1.8 x 10-5):

1.6 x 10-5 M

Which of the following solutions contains the largest number of ions?

600. mL of 0.200 M AlCl3

Consider the gas phase reaction NO + mc001-1.jpgO2 mc001-2.jpg NO2 for which DH° = -56.91 kJ and K =1.46 ´ 106 at 25°C. Calculate DH° at 25°C for the following reaction: 2NO + O2 mc001-3.jpg 2NO2

-113.8 kJ

The removal of copper from metallic ores has been a challenge since ancient times. Strong heating of copper(II) carbonate results in the formation of copper(II) oxide. Although the decomposition of copper(II) oxide into copper metal and oxygen gas is not thermodynamically favorable under standard conditions, it may be made favorable by adding carbon to the mixture. Do this question without a calculator.

-138 kJ/mol

Calculate the DG° for the following equation: Do this without a calculator. 2SO2 + O2

-142 kJ/mol

Consider the gas phase reaction NO + mc002-1.jpgO2 mc002-2.jpg NO2 for which DH° = -56.91 kJ and K =1.46 ´ 106 at 25°C. Calculate DS° at 25°C for the following reaction: 2NO + O2 mc002-3.jpg 2NO2

-146 J/K

You are given the follwoing standard reduction potentials for the two half-reactions: mc004-1.jpg What is the value of DG° for the reaction written below? (Do without a calculator). mc004-2.jpg

-2.17 ´ 106 J

Do without a calculator.

-2.37 volts

Consider the reaction 2N2O5(g) mc003-1.jpg 4NO2(g) + O2(g) at 25°C for which the following data are relevant: DHf° S° N2O5 11.289 kJ/mol 355.32 J/K mol NO2 33.150 kJ/mol 239.90 J/K mol O2 0 kJ/mol 204.80 J/K mol Calculate DG° for the reaction at 25°C.

-25.2 kJ

A popular chemistry demonstration is to drop a piece of sodium metal into water. The products are sodium hydroxide and hydrogen gas. Determine ΔHrxn for this reaction for 1.00 mole of hydrogen gas being produced, given DHf[H2O] = -286 kJ/mol DHf[NaOH] = -470 kJ/mol

-368 kJ

A common car battery consists of six identical cells, each of which carries out the reaction: Pb + PbO2 + 2HSO4- + 2H+ ® 2PbSO4 + 2H2O The value of mc005-1.jpg for such a cell is 2.039 V. Calculate DG° at 25 °C for the reaction.

-393.5 kJ

Determine DG° for a cell that utilizes the following reaction: Cl2(g) + 2Br-(aq) ® 2Cl-(aq) + Br2(l) The standard reduction for the chlorine gas is 1.360 volts and the standard reduction for the bromine liquid is about 1.078 volts.

-54.4 kJ

Consider the gas phase reaction NO + mc004-1.jpgO2 mc004-2.jpg NO2 for which DH° = -56.91 kJ and K =1.46 ´ 106 at 25°C. Calculate DG° at 25°C for the following reaction: 2NO+O2-->2NO2

-70.3 kJ

Determine DG° for the following reaction: CH4(g) + 2O2(g) ® CO2(g) + 2H2O(l)

-818.8 kJ

Determine ΔH for the reaction of methane with oxygen. CH4(g) + 2O2(g)→ 2H2O(g) + CO2(g)

-880 kJ

if 7 moles of sulfur

.33 mol S

(Do without a calculator) Mg2+ + 2e- = Mg -2.37

0.00 V

(Do without a calculator) mc005-1.jpg

0.00 V

(Do without a calculator) mc005-1.jpg (question about Fe and Mg with -2.37V and +0.77)

0.00 V

HA is a weak acid, which is 4.0% dissociated at 0.100 M. Determine the Ka for this acid. Do this without a calculator.

0.00016

how many moles of barium sulfide

0.020 mol

Cesium-137 is a common radioactive product of fission that has many uses in industry and medicine. The half-life of this decay is 30. years. Determine the specific rate constant for this first-order decay. Do this without a calculator.

0.023 yr-1

For a certain reaction, ΔH° = -74.4 kJ and ΔS° = -227 J/K. If n = 3, calculate e° for the reaction at 25°C.

0.0233 V

A solution of MnO42- is electrolytically reduced to Mn3+. A current of 8.07 amp is passed through the solution for 15.0 minutes. What is the number of moles of Mn3+ produced in this process? (1 faraday = 96,485 coulombs)

0.0251

What is the value of k for a first-order reaction with a half-life of 23.1 s? Do this without a calculator.

0.0300 s^-1

What is the approximate density of the hydrogen gas produced at STP if 27.0 g of aluminum metal is added to 333 mL of 3.0 M hydrochloric acid? Solve without using a calculator.

0.1 g/L

Equal volumes of the following pairs of solutions are mixed. Which pair will produce a buffer solution? 0.10 mol L-1 HCl and 0.15 mol L-1 NH3 0.10 mol L-1 HCl and 0.20 mol L-1 CH3COOH 0.10 mol L-1 HCl and 0.05 mol L-1 NaOH 0.10 mol L-1 HCl and 0.05 mol L-1 NH3

0.10 mol L-1 HCl and 0.15 mol L-1 NH3

Consider the following indicators and their pH ranges: Methyl orange 3.2-4.4 Methyl red 4.8-6.0 Bromothymol blue 6.0-7.6 Phenolphthalein 8.2-10.0 Alizarin yellow 10.1-12.0 Assume an indicator works best when the equivalence point of a titration comes in the middle of the indicator range. For which of the following titrations would methyl red be the best indicator?

0.100 M NH3 (Kb = 1.8 ´ 10-5) + 0.100 M HCl

An initial mixture of 5.00 M N2 and 5.00 M H2 is placed in a reaction vessel and allowed to come to equilibrium. The equilibrium concentration of the NH3 is deteremined to be 2.00 M. Determine K for the reaction below. (Do without a calculator)

0.125

The standard free energies of formation of several species are: kJ/mol H+(aq) 0 H2O(l) -237.0 CH3OH(aq) -163.0 HCOOH(aq) -351.2 e- 0 What is the standard reduction potential of methanoic acid in aqueous solution (i.e., for HCOOH + 4H+ + 4e- ® CH3OH + H2O)?

0.126 V

How many moles of sulfuric acid would completely react with 0.30 moles of potassium hydroxide in a titration? Solve without using a calculator.

0.15

The following data were obtained for the reaction, C + D + E ® products. Determine the value of k (do not include units)

0.15

Calculate the pOH of a 0.32 M solution of Ba(OH)2.

0.19

what is the molarity of a solution containing ClO2-

0.20 M

The reduction potential to the metal of Ba2+ is -1.57 V. Given that the cell potential for the reaction 3 Ba(s) + 2 La3+(aq) ® 3 Ba2+(aq) + 2 La(s) is 0.52 V, the reduction potential for La3+(aq) is:

0.52 - (+1.57)

A 57-gram block of metal at 92°C is dropped into an insulated flask containing approximately 45.0 grams of ice and 30.0 grams of water at 0°C. After the system reaches equilibrium it is determined that 9.5 grams of the ice has melted. What is the specific heat of the metal? (Heat of fusion of ice = 333 J/g). Do this without a calculator (estimate the answer).

0.60 J/g °C

Solve without using a calculator. Zinc sulfide reacts with oxygen to yield zinc oxide and sulfur dioxide as follows:

0.67 mol

Calculate the pH of 0.203 M HNO3(aq).

0.693

Determine the standard potential, e°, of a cell that employs the reaction: Fe + Cu2+ ® Cu + Fe2+.

0.781

Nitrogen gas (N2) reacts with hydrogen gas (H2) to form ammonia (NH3). At 200°C in a closed container, 1.0 atm of nitrogen gas is mixed with 2.0 atm of hydrogen gas. At equilibrium, the total pressure is 2.2 atm. Calculate the partial pressure of hydrogen gas at equilibrium.

0.80 atm

Exactly 1.0 mol N2O4 is placed in an empty 1.0-L container and is allowed to reach equilibrium described by the equation N2O4(g) mc004-1.jpg 2NO2(g) If at equilibrium the N2O4 is 37% dissociated, what is the value of the equilibrium constant, Kc, for the reaction under these conditions?

0.87

Determine the mc005-1.jpg for the voltaic cell pictured below. Do this without a calculator. Ag+(aq) + e- = Ag(s)

0.94V

Nitric acid reacts with silver metal

0.999 g

Nitric acid reacts with silver metal: 4HNO3 + 3AG = NO + 2H2O + 3AgNO3. Calculate the number of grams of NO formed when 10.8 g of Ag reacts with 12.6 of HNO3

0.999 g

Balance the following redox equation in basic solution. What is the coefficient of the hydroxide ion? NO2-(aq) + Al(s) ® NH3(g) + AlO2-(aq)

Balance the following redox equation in basic solution. What is the coefficient of the water? NO2-(aq) + Al(s) ® NH3(g) + AlO2-(aq)

What is the subscript of barium in the formula of barium sulfate?

Which of the following most closely estimates the density of air at 1.0 atm and 25 degree Celsius to one significant figure?

1 g/L

1 gram of mercury is sealed in a glass tube. The tube is heated slightly and all of the mercury vaporizes. What mass of mercury remains in the tube?

1 gram because the number of atoms has not changed.

How many moles of solid chromium can be deposited from a CrCl3 solution when a steel wrench is electroplated with a current of 3.0 amps for 965 seconds? Do this without a calculator.

1.0 ´ 10-2

How many moles of HCl need to be added to 150.0 mL of 0.50 M NaZ to have a solution with a pH of 6.50? (Ka of HZ is 2.3 ´ 10-5)? Assume negligible volume of the HCl.

1.0 ´ 10-3

Determine the molarity of a solution that is made by dissolving 20.0 g of ammonium nitrate, NH4NO3, in enough water to make 250.0 mL of solution.

1.00 M

Which of the following solutions contains the strongest acid? 5.00 M HCN (Ka = 6.2 x 10-10) 1.00 M HF (Ka = 7.2 x 10-4) 4.00 M HOCl (Ka = 3.5 x 10-8) 3.50 M H2C6H6O6 (Ka1 = 7.9 x 10-5, Ka2 = 1.6 x 10-12).

1.00 M HF (Ka = 7.2 x 10-4)

A reaction is first order with respect to [X] and second order with respect to [Y]. When [X] = 0.20 M and Y = 0.20 M the rate is 8.00 ´ 10-3 M min-1. The value of the rate constant, including correct units, is: (Do this without a calculator)

1.00 M-2 min-1

The following question refers to a galvanic cell that utilizes the following reaction (unbalanced): (AuCl4)-(aq) + Cu(s) ® Au(s) + Cl-(aq) + Cu2+(aq) Given the following information, determine the standard cell potential: Species Standard Reduction Potential (V) Au3+(aq) 1.4980 Cu2+(aq) 0.3390

1.1590 V

Gold (atomic mass = 197.0) is plated from a solution of chloroauric acid, HAuCl4; it deposits on the cathode. Calculate the time it takes to deposit 0.30 gram of gold, passing a current of 0.10 amperes. (1 faraday = 96,485 coulombs)

1.2 hours

For the reaction N2O4(g) mc001-1.jpg 2NO2(g), Kp = 0.148 at a temperature of 298 K. What is Kp for the following reaction? 10NO2(g) mc001-2.jpg 5N2O4(g)

1.41 x 104

Sucrose

1.45 x 10^25 atoms

A + 2B = C What is the rate of disappearance of B in trial 2? Do this without a calculator.

1.4´ 10-3 mol L-1s-1

What is the rate of disappearance of B in trial 2? Do this without a calculator.(A+2B = C)

1.4´ 10-3 mol L-1s-1

A 20.0.-g sample of metal at 110.°C is placed into 30. g of kerosene at 35°C. The final temperature of both the kerosene and the metal is 60°C. If the specific heat of kerosene is 2.0 J/°C . g, what is the specific heat of the metal.

1.5 J/°C

Refer to the galvanic cell below (the contents of each half-cell are written beneath each compartment): 0.10 M MnO4- 0.40 M Cr3+ 0.20 M Mn2+ 0.30 M Cr2O72- 0.010 M H+ 0.010 M H+ The standard reduction potentials are as follows: MnO4- + 8H+ + 5e- → Mn2+ + 4H2O, e° = 1.51 V Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O, e° = 1.33 V What is the value of Q, the reaction quotient, for this cell reaction?

1.5 x 10-41

How many moles of CaF2 will dissolve in 3.0 liters of 0.089 M NaF solution? (Ksp for CaF2 = 4.0 ´ 10-11)

1.5 x 10-8

What concentration of acetic acid (Ka = 1.80 x 10-5) has the same pH as that of 5.33 x 10-3 M HCl?

1.58 M

In a closed rigid system, 7.0 mol CO2 , 7.0 mol Ar, 7.0 mol N2 , and 4.0 mol Ne are trapped, with a total pressure of 10.0 atm. What is the partial pressure exerted by the neon gas? Solve without using a calculator.

1.6 atm

Consider the reaction 2N2O5(g) mc001-1.jpg 4NO2(g) + O2(g) at 25°C for which the following data are relevant: DHf° S° N2O5 11.289 kJ/mol 355.32 J/K mol NO2 33.150 kJ/mol 239.90 J/K mol O2 0 kJ/mol 204.80 J/K mol Calculate DH° for the reaction.

110.022 kJ

Nitroglycerine, C3H5N3O9, explodes with tremendous force due to the numberous gaseous products. The unbalanced equation for the explosion of nitroglycerine is shown below. What is the coefficient of the CO2(g) when the equation is balanced using the lowest whole number coefficients?

A 5.00-L vessel contains 2.00 moles of helium and 3.00 moles of hydrogen at a pressure of 10.0 atm. Maintaining a constant temperature, an additional 3.00 moles of hydrogen are added. What is the partial pressure of hydrogen gas in the vessel at the end? (Assume that the gases behave ideally.) Solve without using a calculator.

12.0 atm

The Ksp of a hypothetical metllic hydroxide, MOH, is 1.0 ´ 10-4. What is the pH of a saturated solution of MOH? Do this without a calculator

12.00

How many peaks would be displayed in an X-ray PES emission spectrum of mercury (Z=80)?

The first ionization energy of magnesium is 738 kJ/mol. A good estimate for the second ionization energy of magnesium is

1450 kJ/mol

The mass spectrum of a sample of radioactive plutonium recovered from a nuclear reactor is shown below. mc003-1.jpg Using the graph, determine the number of neutrons in the isotope of plutonium having the greatest abundance in this sample

150

Hydrogen gas, iodine vapor, and hydrogen iodide gas are added to an evacuated flask until the concentrations of H2 and I2 are both 2.0M and that of HI equals 8.0M. Determine the value of Q without using a calculator.

Nickel is electroplated from a NiSO4 solution. A constant current of 5.50 amp is applied by an external power supply. How long will it take to deposit 100. g of Ni? The atomic mass of Ni is 58.69.

16.6 h

What mass of chromium could be deposited by electrolysis of an aqueous solution of Cr2(SO4)3 for 145 minutes using a constant current of 11.0 amperes?

17.2 g

What volume of H2O measured at STP is produced by the combustion of 6.27 g

17.5 L

Determine DG° for the weak acid, HF, at 25°C. (Ka = 7.16 ´ 10-4)

17.9 kJ

Solve without using a calculator. Hydrogen reacts with oxygen to form only water If 16 grams of hydrogen is mixed with 16 grams of oxygen, how much water can form?

18 grams

the observed first-order rate of decay of carbon-14 in living material...

1800 years

What is the electron configuration for Zn2+?

1s22s22p63s23p63d10

What is the element's electron configuration?(150, 12.1)

1s^22s^22p^63s^23p^1

Balance the following redox equation in basic solution. What is the coefficient of the water? MnO4-(aq) + HCOOH(aq) ® Mn2+(aq) + CO2(g)

How many electrons are transferred in the following reaction? Sn + 2HCl = SnCl2 + H2

If the concentration of the HF in this reaction is 0.1 M, what is an approximate pH of the solution? Do this without a calculator. *PICTURE OF EQN NOT INCLUDED

Which of the following is nonpolar?

2 B's and two dots on top and below the A

Solve without using a calculator. Which of the following reaction mixtures would produce the greatest amount of product, assuming all went to completion? Each involves the reaction symbolized by the equation: N2(g) + 3H2(g) ----> 2NH3(g) 5 mol N2 and 1 mol H2 1 mol N2 and 5 mol H2 4 mol N2 and 2 mol H2 2 mol N2 and 4 mol H2

2 mol N2 and 4 mol H2

Which of the following aqueous solutions will have the highest pH? For NH3, Kb = 1.8 x 10-5; for C2H3O2-, Kb = 5.6 x 10-10.

2.0 M NaOH

Barium iodate has a Ksp of 4.0 ´ 10-9. What is the iodate ion concentration in a saturated solution of barium iodate? Do this without a calculator.

2.0 ´ 10-3 M

HA is a weak, monoprotic acid that dissociated according to the equation mc003-1.jpg If the initial concentration of HA is 0.10 M, find the concentration of H1+. Do this without a calculator.

2.0 ´ 10-5 M

When 1.00 mole of zinc is consumed in the following reaction, how many faradays are transferred? (Do without a calculator) mc006-1.jpg

2.00

Consider the gas phase reaction NO + mc003-1.jpgO2 mc003-2.jpg NO2 for which DH° = -56.91 kJ and K =1.46 ´ 106 at 25°C. Calculate K for the following reaction at 25°C: 2NO + O2 mc003-3.jpg 2NO2

2.13 ´ 1012

The following question refers to the following system: 3Ag(s) + NO3-(aq) + 4H+(aq) ® 3Ag+(aq) + NO(g) + 2H2O(l) Note: The cell potentials below are for the reactions as they are written (so you don't need to flip). Anode reaction: Ag ® Ag+(aq) + 1e- e° = -0.7990 V Cathode reaction: NO3-(aq) + 4H+(aq) + 3e- ® NO(g) + 2H2O(l) e° = 0.9636 V Determine the equilibrium constant at 25°C.

2.266 x 10^8

2.266X10^8

15.0 mL of 0.50 M HCl is added to a 100.-mL sample of 0.456 M HNO2 (Ka for HNO2 = 4.0 ´ 10-4). What is the equilibrium concentration of NO2- ions?

2.4 ´ 10-3 M

A common car battery consists of six identical cells each of which carries out the reaction: Pb + PbO2 + 2HSO4- + 2H+ ® 2PbSO4 + 2H2O Suppose that in starting a car on a cold morning a current of 125 amperes is drawn for 18.4 seconds from a cell of the type described above. How many grams of Pb would be consumed? (The atomic weight of Pb is 207.19.)

2.47 g

Ammonia and oxygen react to establish the following equilibrium

2.5 mol

If an acid, HA, is 14.7% dissociated in a 1.0 M solution, what is the Ka for this acid?

2.5 x 10-2

The Ksp for PbF2 is 4.0 ´ 10-8. If a 0.040 M NaF solution is saturated with PbF2, what is the [Pb2+] in the solution?

2.5 x 10-5

Consider the titration of 100.0 mL of 0.250 M aniline (Kb = 3.82 ´ 10-10) with 0.500 M HCl. Calculate the pH of the solution at the stoichiometric point.

2.68

Solve without using a calculator. How many moles of electrons are transferred between the substance being oxidized and the substance being reduced in the reaction given below? 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l)

The total pressure is observed to be 58 atm. What is the partial pressure of the water vapor produced?

20. atm

How many Grams of chromium in 58.5

20.8

Solve without using a calculator. Which of the following is a reasonable estimate for the volume of a balloon that has been filled with 300 g of oxygen gas at STP?

200 L

Solve without using a calculator. What volume of 0.2000 M sulfuric acid is required to neutralize 800.0 mL of 0.1000 M potassium hydroxide?

200.0 mL

At 25°C the following heats of reaction are known: 2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(l) ΔH = -2600.0 kJ C(graphite) + O2(g) → CO2(g) ΔH = -394 kJ 2H2(g) + O2(g) → 2H2O(l) ΔH = -574 kJ At the same temperature, calculate ΔH for the reaction 2C(graphite) + H2(g) → C2H2(g)

225 KJ

225 kJ

The reaction below occurs in basic solution. In the balanced equation, what is the sum of tThe removal of copper from metallic ores has been a challenge since ancient timeshe coefficients? Zn + NO3- ® Zn(OH)42- + NH3

What is ΔG° for the following electrochemical equation? (e°red(Ag+/Ag) = 0.800 V, e°red(Cd2+/Cd) = -0.403 V) 2Ag(s) + Cd2+(aq) → 2Ag+(aq) + Cd(s)

232 kJ/mol

Gold-198 is a radioactive isotope that is used to treat several types of cancer. Its first-order decay has a half-life of 2.7 days. How many grams must a physician order for a treatment that will begin in 11 days, if approximately 15 grams of gold-198 is needed for the treatment? Do without a calculator.

240 g

consider 100 ml of 1.00m solution of NaCl

25.0 mL

Copper is electroplated from CuSO4 solution. A constant current of 3.19 amp is applied by an external power supply. How long will it take to deposit 1.00 ´ 102 g of Cu? The atomic mass of copper is 63.546.

26.4 h

Given CH3CO2H(aq) mc027-1.jpg H+(aq) + CH3CO2-(aq) at 25°C, Ka = 1.84 ´ 10-5. What is DG° at 25°C?

27.0 kJ

The half-life for the first-order nuclear decay of a 10.0 g sample of strontium-90 is 28 years. What is the half-life of a 5.0 g sample of strontium-90? Do this without a calculator.

28 years

You have 41.6 g of O2 gas in a container with twice the volume as one with CO2 gas. The pressure and temperature of both containers are the same. Calculate the mass of carbon dioxide gas you have in the container.

28.6 g

For which of the following processes would DS° be expected to be most positive?

2NH4NO3(s) ® 2N2(g) + O2(g) + 4H2O(g)

2molN2 4molH2

How many on the following molecules have two pi bonds? HCN, C2H2, CO2, OCl2

Sketch the PES plot for carbon atoms. How many peaks would you expect?

a graduated cylinder contains multiple different liquid layers very small samples are taken from the liquids at various heights and tested for density,...

Magnesium reacts with hydrochloric acid to produce hydrogen gas. An experiment was set up to determine the rate of production of the hydrogen gas by measuring its change in volume over the first 60 seconds of the reaction.

3 M HCl, 0.5-cm2 pieces of magnesium

plutonium-243 decays into americanium-243...

3 columns of dark balls and last column is white balls

For two first-order reactions of different substances A and X mc007-1.jpg This means that

3 moles of A will react more rapidly than 3 moles of X

Hydrogen gas at a pressure of 9.0 atm is added to a container containing 5.0 atm of iodine vapor. The resulting reaction is allowed to come to equilibrium, and it is found that the final pressure of iodine vapor is 2.0 atm. What is the Kp value for the following reaction? (Do without using a calculator).

3.0

The reaction of CH3CBr with hydroxide ion proceeds with the formation of

3.0 ´ 10-3

The reaction vessel at this point is then heated to 657°C, where the equilibrium concentration of the HI is determined to be 6.0 M. What is the K value at 657°C? (Do without a calculator)

4.0

The salt MX2 has a solubility of 1.0 ´ 10-4 M. Determine the Ksp for MX2. Do this without a calculator.

4.0 ´ 10-12

Ammonium hydrogen sulfide will decompose into ammonia gas and hydrogen sulfide gas when heated. Consider the equilibrium system

4.00 ´ 10-2

Ammonium hydrogen sulfide will decompose into ammonia gas and hydrogen sulfide gas when heated. Consider the equilibrium system mc010-1.jpg which is developed from 1.000 mole of NH4HS in a 100-L cylinder. At equilibrium the total pressure is found to be 0.400 atm. Solving without a calculator, Kp will be equal to

4.00 ´ 10-2

Consider the following equilibrium: 2NOCl(g) mc009-1.jpg 2NO(g) + Cl2(g) with K = 1.6 x 10-5. 1.00 mole of pure NOCl and 0.958 mole of pure Cl2 are placed in a 1.00-L container. Calculate the equilibrium concentration of NO(g).

4.09 x 10-3 M

Calculate the pH of a 0.13 M solution of HOCl, Ka = 3.5 x 10-8.

4.17

The solubility of La(IO3)3 in a 0.42 M KIO3 solution is mc010-1.jpg mol/L. Calculate the Ksp for La(IO3)3.

4.2 x 10-13

An antique automobile bumper is to be chrome plated. The bumper, which is dipped into an acidic mc002-1.jpg solution, serves as a cathode of an electrolytic cell. The atomic mass of Cr is 51.996; 1 faraday = 96,485 coulombs. If oxidation of H2O occurs at the anode, how many moles of oxygen gas will evolve for every 151 grams of Cr(s) deposited?

4.36

What is the sodium ion concentration when 70.0 mL of 3.0 M Na2CO3 is added to 30.0 mL of 1.0 M NaHCO3? Do this without a calculator.

4.5 M

minerals containing uranium can be dated...

4.5 billion years

Calculate the pH of the following aqueous solution: 0.39 M NH4Cl (pKb for NH3 = 4.74)

4.83

Calculate the percentage of pyridine (C5H5N) that forms pyridinium ion, C5H6N+, in a 0.72 M aqueous solution of pyridine (Kb = 1.7 ´ 10-9).

4.9 ´ 10-3 %

a sample of 25ml .120 CaOH

40ml

consider the neutralization reaction BeOH

40ml

For the reaction below, Kp = 1.16 at 800.°C CaCO3

42.1%

As O2(l) is cooled at 1 atm, it freezes at 54.5 K to form Solid type I. At a lower temperature, Solid type I rearranges to Solid type II, which has a different crystal structure. Thermal measurements show that DH for the type I ® type II phase transition is -743.07 J/mol, and DS for the same transition is -17.0 J/K mol. At what temperature are Solid types I and II in equilibrium?

43.7 K

Elemental sulfur exists in two crystalline forms, rhombic and monoclinic. From the following data, calculate the equilibrium temperature at which monoclinic sulfur and rhombic sulfur are in equilibrium. DHf° (kJ/mol) S° (J/K mol) S (rhombic) 0 31.880 S (monoclinic) 0.30 32.552

446 K

Determine the volume of distilled water that should be added to 20.0 mL of 12.0 M HCl(aq) in order to prepare a 0.500 M HClaq) solution

460. mL

If K = 0.144 for A2 + 2B mc008-1.jpg 2AB, then for 4AB mc008-2.jpg 2A2 + 4B, K would equal:

48.2

The correct mathematical expression for finding the molar solubility (s) of calcium phosphate is:

4s3 = Ksp

Which of the following solutions will be the best buffer at a pH of 9.26? (Ka for HC2H3O2 is 1.8 ´ 10-5, Kb for NH3 is 1.8 ´ 10-5).

5.0 M NH3 and 5.0 M NH4Cl

Consider the reaction mc005-1.jpgmc005-2.jpgmc005-3.jpgAt 1273 K, the Kp value is 167.5. What is the mc005-4.jpg at equilibrium if the mc005-5.jpg is 0.17 atm at this temperature?

5.3 atm

Calculate Kp for H20

5.4 x 10-13

Calculate Kp for mc002-1.jpgmc002-2.jpgmc002-3.jpg using the following data:

5.4 x 10-13

Initially 2.0 moles of N2(g) and 4.0 moles of H2(g) were added to a 1.0-liter container and the following reaction then occurred:

5.5 x 10-3

A solution containing 10. mmol of mc011-1.jpgand 5.0 mmol of mc011-2.jpgis titrated with 1.8 M HCl. What volume of HCl must be added to reach the first equivalence point?

5.6 mL

Which of the following pairs of 0.100 mol L-1 solutions, when mixed, will produce a buffer solution? 50 mL of aqueous CH3COONa and 25 mL aqueous NaOH 50 mL of aqueous CH3COOH and 25 mL aqueous HCl 50 mL of aqueous CH3COOH and 25 mL aqueous CH3COONa 50 mL of aqueous CH3COOH and 100 mL aqueous NaOH

50 mL of aqueous CH3COOH and 25 mL aqueous CH3COONa

How much 12.0 M hydrochloric acid must be used to prepare 2.00 L of a 3.00 M hydrochloric acid solution? Do this without a calculator.

500.0 mL

Consider a weak acid, HX. If a 0.10 M solution of HX has a pH of 5.64 at 25°C, what is DG° for the acid's dissociation reaction at 25°C?

58.6 kJ

Balance the following redox equation in basic solution. What is the coefficient of the hydroxide ion? MnO4-(aq) + HCOOH(aq) ® Mn2+(aq) + CO2(g)

The following reaction occurs in aqueous acid solution: NO3- + I- ® IO3- + NO2 In the balanced equation the coefficient of NO3- is:

At 65°C, the ion-product constant of water, Kw, is 1.20 x 10-13. The pH of pure water at 65°C is:

6.460

What is the pOH of pure water at 65oC? (Kw at 65oC = 1.20 ´ 10-13)

6.460

What is the pOH of pure water at 65°C? (Kw at 65°C = 1.20 x 10-13)

6.460

For the reaction N2O4(g) mc001-1.jpg 2NO2(g), Kp = 0.148 at a temperature of 298 K. What is Kp for the following reaction?

6.76

In the reaction, NO3(g) + CO(g) → NO2(g) + CO2(g) the carbon in CO must collide with an oxygen in NO3 with sufficient energy to react. Which of the diagrams below would most likely result in the formation of products?

60°C

What is the pH of a 0.73 M KCl solution?

7.00

For a certain process at 355 K, DG = -11.8 kJ and DH = -9.2 kJ. Therefore, DS for the process is

7.3 J/K mol

An ideal gas of volume 189. mL is collected over water at 30 degrees Celsius and 777 torr. The vapor pressure of water is 32 torr at 30 degrees Celsius. What pressure is exerted by the dry gas under these conditions? You should be able to do this without a calculator.

745 torr

Solve without using a calculator. Substance AB2 is 60.0% A by mass. What is the percent A by mass for substance AB?

75.0%

A 10-lane Olympic-sized swimming pool contains 2.5 x 106 Kg of water. If the water is at 0°C, how many kilojoules of energy must be removed to freeze the water in this pool? ΔHfus for water is 334 J/g. You can solve this without a calculator by estimating. Remember, MC questions on the actual AP exam are done without a calculator.

8.4 x x 108 kJ

8.4 x x 10^8 kJ

Calculate the solubility product of silver iodide at 25°C given the following data: e°(V) AgI(s) + e- ® Ag(s) + I- -0.15 I2(s) + 2e- ® 2I- +0.54 Ag+ + e- ® Ag(s) +0.80

8.4 ´ 10-17

a 25.0 mL sample of 0.10 M...

8.72

When iron(III) oxide is heated with carbon, the products are iron metal and carbon monoxide. Balance the quation in standard form and determine the sum of the coefficients.

Consider mc004-1.jpg The reaction was initiated by adding 15.0 moles of NO to a 1.0-L flask. At equilibrium, 3.0 moles of oxygen are present in the 1.0-L flask. The value of K (do without a calculator) must be

9.0

Consider this reaction at STP: C2H6(g) + 7/2O2(g)

9.00 L

Hypobromous acid, HOBr, has an acid dissociation constant of 2.5 x 10-9 at 25°C. What is the pOH of a 0.075 M HOBr solution?

9.14

Calculate the pH of a 0.49 M solution of NaC2H3O2 (for HC2H3O2 Ka = 1.8 x 10-5).

9.22

The solubility of an unknown salt, M2Z, in a 0.0768 M CaZ solution is mc011-1.jpg mol/L. Calculate the Ksp for M2Z.

9.6 x 10-20

The standard molar free energies of formation of NO2(g) and N2O4(g) at 25°C are 51.840 and 98.035 kJ/mol, respectively. What is the value of Kp (in atm) for the reaction written as follows at 25°C?

9.76

Gas A2 reacts with B2 to form gas AB at constant temperature.

Indicate which of the above graphs represents PV (y-axis) vs. n (x-axis) for an ideal gas at constant T.

Which of the following has Sp3 hybridization and is bent?

Which of the following statements is true concerning ideal gases?

A gas exerts pressure as a result of the collisions of the gas molecules with the walls of the container.

A 25-mL sample of ethanol is slowly heated to 80 °C using a hot plate. The volume of ethanol in the beaker gradually decreases to 10 mL. What is the best conclusion for what is occurring to the ethanol?

A physical change is occurring because the hydrogen bonds are being broken.

Given the following data (DHf, S°, respectively) for N2O4(l) -20. kJ/mol, 209.0 J/K mol, and N2O4(g) 10. kJ/mol,304.2 J/K mol. Above what temperature (in °C) is the vaporization of N2O4 liquid spontaneous?

Above 42 °C

Ag+(aq) + e- = Ag(s) Which of these changes would increase the value of mc006-2.jpg?

Add 1.5 g of AgNO3 to the left beaker.

Which of these changes would increase the value of E0?

Add 1.5 g of AgNO3 to the left beaker.

What is the correct balanced net ionic equation for the reaction illustrated?

Ag+ + Cl- = AgCl-

Which of the following statements is true concerning the relative solubility of silver chloride? All samples are at the same temperature.

AgCl is less soluble in 1.0 M AgNO3 than it is in pure water.

You wish to plate out zinc metal from a zinc nitrate solution. Which metal, Al or Ni, could you place in the solution to accomplish this?

Which of the following solutions is INCORRECTLY described? I. 0.2 M NaCN has a pH > 7. II. 0.2 M FeBr3 is acidic III. 0.25 M NH4Cl is acidic

All are correctly described

Which beaker would have the highest hydrogen ion concentration?

All have the same hydrogen ion concentration.

Which of the following properties of water is/are due to the intermolecular hydrogen bonding between the water molecules? Ice floats on water. Water has a high heat of vaporization. The specific heat of water (4.184 J/g °C) is much higher than that of lead (0.128 J/g °C). All of the above.

All of the above.

Which best explains why an aluminum can may be crushed without it breaking into pieces?

Aluminum has delocalized valence electrons with nondirectional bonding.

If the reverse reaction that what is shown above was desired, how could it be obtained in the laboratory?

Apply an electrical potential greater than the mc008-3.jpg for the forward reaction.

Given the following data: Ca2+(aq) + 2e- = Ca(s) E = -2.87V Which of the following correctly describes the ease of oxidation of the substances listed under standard state conditions?

Ca > Zn > Co > Sn > Pb

Which of the following is the reason that ionization energy generally increases from left to right across the scond period of the periodic table?

As the atomic number increases, more protons in the nucleus cause an increase in the effective nuclear charg, making it harder to remove the electrons.

The exothermic reaction, 2 Cu(s) + O2(g) " 2 CuO(s), is spontaneous

At low temperatures

Sodium chloride is added slowly to a solution that is 0.010 M in Cu+, Ag+, and Au+. The Ksp values for the chloride salts are 1.9 ´ 10-7, 1.6 ´ 10-10, and 2.0 ´ 10-13, respectively. Which compound will precipitate first?

AuCl

Aqueous solutions of Na2CO3 and Ca(NO3)2

The Maxwell-Boltzmann distribution for an unknown gas is shown. At which point on the graph is the average temperature of the gas most directly related to its translational kinetic energy?

When propane burnse in air, heat is released.

B(-+-)

HA and HB are both weak acids in water, and HA is a stronger acid than HB. Which of the following statements is correct?

B- is a stronger base than A-, which is a stronger base than H2O, which is a stronger base than Cl-.

Metal A is more easily oxidized than metal B. What is true of A1+ and B1+?

B1+ is more easily reduced than A1+ and also If a strip of metal B is plated with metal A, the metal A plating will corrode first.

Which reaction would have the most positive DS°?

Ba(OH)2 · 8H2O(s) + 2NH4NO3(s) ® Ba(NO3)2(s) + 2NH3(g) + 10H2O(l)

Which of the following pairs is incorrect? NH4Br, ammonium bromide K2CO3, potassium carbonate BaPO4, barium phosphate CuCl, copper(I) chloride MnO2, manganese(IV) oxide

BaPO4, barium phosphate

A 0.012-mol sample of Na2SO4 is added to 400 mL of each of two solutions. One solution contains 1.5 ´ 10-3 M BaCl2; the other contains 1.5 ´ 10-3 M CaCl2. Given that Ksp for BaSO4 = 1.5 ´ 10-9 and Ksp for CaSO4 = 6.1 ´ 10-5:

BaSO4 would precipitate but CaSO4 would not.

A .010-mole sample of K2SO4 is added to 1.0 L

BaSO4 would precipitate, but Ag2SO4 would not.

A 25.0 mL sample of an unknown monoprotic acid was titrated with 0.12 M NaOH. The student added 31.6 mL of NaOH and went past the equivalence point. Which procedure could be performed next to more accurately determine the concentration of the unknown acid?

Back-titrate with additional HCl to neutralize the additional NaOH that was added.

If 50 mL of 0.1 M NaOH was added to each beaker, which resulting solution would have the lowest pH?

Beaker 2 would have the lowest pH

Which of the following has a bent molecular geometry with a bond angle of approximately 120 degrees?

Big A with 2 dots and 2 small B's

The quantum mechanical atomic model replaced the Bohr atomic model because

Bohr's model could not predict the spectra for elements other than hydrogen.

Which of the following is true?

By thermodynamically favored we mean that the reaction or process will always proceed to the right (as written) even if very slowly. Increasing the temperature may speed up the reaction, and it generally affects the spontaneity of the reaction.

A 100-mL sample of water is placed in a coffee-cup calorimeter. Solid NaCl is then dissolved in the water. The temperature of the water decreases from 20.5°C to 19.7°C and is then allowed to return to room temperature (20.5°C). Determine the signs for DH and DS for the process of dissolving NaCl and DG for the entire process at constant temperature. (NaCl is the system).

What point on the graph represents pKa2?

Which of the following conditions most favors the process of dissolution?

Which of the following equations satisfies the law of conservation of mass? C(s) + O2(g) → CO2(g) Na(s) + Cl2(g) → NaCl(s) H2(g) + O2(g) → H2O(g) N2(g) + H2(g) → NH3(g)

C(s) + O2(g) → CO2(g)

Indicate which of the above graphs represents PV (y-axis) vs. V (x-axis) for 1.0 mole of an ideal gas at constant T.

C(straight line hor.)

The vapor pressure increases in a predictable order as shown as

C2H5-OH

Rank the following from lowest to highest boiling temperature: C2H6 C2H5OH C2H5Cl

C2H6 < C2H5Cl <C2H5OH

Each of the following salts has a solubility of 1.0 ´ 10-5 M. Rank the salts in order of lowest to highest Ksp. AX, B2X, C2X3, D3X

C2X3 < D3X < B2X < AX

Order the following solvents from least polar to most polar: C6H14 H2O CH3OH CHCl3

C6H14 < CHCl3 < CH3OH < H2O

Which of the following processes should show the greatest increase in entropy?

C6H6(l) + 15/2 O2(g) " 6 CO2(g) + 3 H2O(g)

Which of these compounds would you predict to have the highest boiling point?

CBr4

An aqueous solution of which of these compounds would have a pH greater than 8.0?

CH3NH2

Which compound would be expected to be the most soluble in water?

CH3NH2

Of HCO31-, CO32-, CO2, and CO, which one has the shortest C-O bond length?

solutions of CaCl2 and Na2CO3

CO32-

Which solute would dissolve in carbon tetrachloride, CCl4?

CS2

Three ionic salts, AX, BX2, and CX3, each have a solubility of 2 ´ 10-5 M. Which of the following correctly ranks the Ksp of the three salts from least to greatest?

CX3 < BX2 < AX

A student is trying to find the activation energy of a reaction. What technique could be used?

Choose one set of reactant concentrations and run the same reaction at different temperatures.

The half-reaction below that is written correctly is:

Cl2 + 2e- → 2Cl^1-

Cl2 and F2 combine to form a gaseous product; one volume of Cl2 reacts with three volumes of F2 yielding two volumes of product. Assuming constant conditions of temperature and pressure, what is the formula of the product? Solve without using a calculator.

ClF3

Given the following values of pKa, determine which is the weakest base of the answers listed. Acid pKa HClO2 1.95 HClO 7.54 HCOOH 3.74 HF 3.17 HNO2 3.15

ClO2-

Which of the following is incorrectly named?

ClO3-, chlorite ion

pure silver is generally considered too soft to form...

Copper has a smaller radius than silver, disturbing the crystal structure and making the alloy harder.

Solve without using a calculator. Analysis of a sample of an oxide of chromium is reported as 26 g of chromium and 12 g of oxygen. From these data determine the empirical formula of this compound.

Cr2O3

Consider the freezing of liquid water at -10°C. For this process, what are the signs for DH, DS, and DG?

The photoelectron emission spectrum for an unknown element is shown above. It's known that the element is NOT an alkali metal. The peak that corresponds to the valence electrons within the atom is

The photoelectron spectrum for an unknown element is shown above. It's known that the element is NOT an alkali metal. The peak that corresponds to the valence electrons within the atom is

Indicate which of the above graphs represents gas density (y-axis) vs. T (x-axis) for 1.0 mole of an ideal gas at constant P.

D(left to right curve)

Consider the DG of four different combinations of DH and DS. Assume that both DH and DS are temperature independent. Which of these four processes is improbable at a low temperature, but becomes more probable as the temperature rises?

DH = (+) and DS = (+)

Consider the DG of four different combinations of DH and DS. Assume that both DH and DS are temperature independent. The process which is nonspontaneous at all values of temperaure is

DH = (+) and DS = (-)

Consider the DG of four different combinations of DH and DS. Assume that both DH and DS are temperature independent. Which processes are spontaneous at all temperature?

DH = (-) and DS = (+)

For endothermic reactions at constant pressure

DH > 0

A student performs a neutralization reaction involving an acid and a base in an open polystyrene coffee-cup calorimeter. How would the calculated value of DH differ from the actual value if there was significant heat loss to the surroundings?

DH calc would be negative, but less negative than the actual value (whether that actual value is positive or negative).

In which case must a reaction be spontaneous at all temperatures?

DH is negative, DS is positive.

Consider the reaction 2N2O5(g) mc002-1.jpg 4NO2(g) + O2(g) at 25°C for which the following data are relevant: DHf° S° N2O5 11.289 kJ/mol 355.32 J/K mol NO2 33.150 kJ/mol 239.90 J/K mol O2 0 kJ/mol 204.80 J/K mol Which of the following is true for this reaction?

DH° opposes the reaction, but DS° favors it.

DS is positive because the products have more moles of gas than the reactant.

A representation of the bonding in solid silver is shown below. mc012-1.jpg This representation best shows which of the following?

Each silver atom has one valence electron that is free to move throughout the piece of metal, allowing silver to conduct electricity.

Consider the galvanic cell shown below (the contents of each half-cell are written beneath each compartment): mc027-1.jpg 0.50 M Br2 0.20 M Cr3+ 0.10 M Br- The standard reduction potentials are as follows: Cr3+(aq) + 3e- ® Cr(s) e° = -0.73 V Br2(aq) + 2e- ® 2Br-(aq) e° = +1.09 V Which of the following statements about this cell is false?

Electrons flow from the Pt electrode to the Cr electrode.

Consider a closed flask containing a liquid and its vapor. Which statement is incorrect?

Evaporation and condensation will eventually cease after a constant pressure has been attained.

The reduction potentials of three alkali metals are given in the table below, along with the reduction potential of water. Given that reactions with more positive cell potentials are more thermodynmically favorable, what is the best explanation for the fact that the reaction of lithium with water occurs more slowly than the reaction of either sodium or potassium with water?

Even though the reaction of lithium with water is thermodynamically favorable, it is kinetically slow. (maybe not too sure)

In the reaction: MnO4 + 5Fe2+ + 8H+ = Mn2+ + 5Fe3+ + 4H2O

Fe2+ is oxidized and MnO41- is reduced.

Two unlabeled Erlenmeyer flasks each contained 25.00 mL of solution at pH 4.00. Each flask was titrated with the same standardized NaOH solution. The volumes needed to reach the endpoint are listed in the table below. What claim can be made about the acids in flasks A and B?

Flask A was a strong acid because less titrant was needed to reach the endpoint.

Which of the following systems at equilibrium are not affected by a change in pressure caused by changing the volume at constant temperature?

H2 + Cl2

The value of the equilibrium constant, K, is dependent on: I. the temperature of the system II. the nature of the reactants and products III. the concentration of the reactants IV. the concentration of the products

I, II

Consider the following information about the diprotic acid, ascorbic acid. (H2As for short, molar mass 176.1) H2As mc027-1.jpg HAs- + H+ pKamc027-2.jpg = 4.10 (Kamc027-3.jpg = 7.9 ´ 10-5) HAs- mc027-4.jpg As2- + H+ pKamc027-5.jpg = 11.79 (Kamc027-6.jpg = 1.6 ´ 10-12) The titration curve for disodium ascorbate, Na2As, with standard HCl is shown below:

H2As

The conjugate acid and conjugate base of bicarbonate ion, HCO3-, are, respectively:

H2CO3 and CO32-

In which of the following processes is there an increase in entropy?

H2O2(l) ® H2O(l) + 1/2 O2(g)

For the stepwise dissociation of aqueous H3PO4, which of the following is not a conjugate acid-base pair?

H2PO4- and PO43-

For the stepwise dissociation of aqueous H3PO4, which of the following is not a conjugate acid-base pair? H2PO4- and HPO42- HPO42- and PO43- H3PO4 and H2PO4- H2PO4- and PO43-

H2PO4- and PO43-

What is the conjugate acid of HPO42-?

H2PO41-

Suppose a buffer solution is made from formic and (HCHO2) and sodium formate (NaCHO2). What is the net ionic equation for the reaction that occurs when a small amount of hydrochloric acid is added to the buffer?

H3O+(aq) + CHO2-(aq) ® HCHO2(aq) + H2O(l)

Which acid solution has a greater pH?

HA because it dissociates less than HX

the mechanism below shows how ethanol is converted into ethene

HA reacts with CH3CH2OH to produce CH2CH2 + H2O + HA

All of the following are in aqueous solution. Which is incorrectly named?

HBr, bromic acid

Consider 100.0 mL of 0.100 M aqueous solutions each of the following acids: HCN, HF, HCl, HC2H3O2. Each acid is titrated with 0.100 M NaOH(aq). Once the equivalence point is reached for each solution, rank the pH values from highest to lowest.

HCN, HC2H3O2, HF, HCl

consider 100ml of a .100M aqueous solution of the following acids: HCN, HF, HCL, HC2H3O2

HCN, HC2H3O2, HF, HCl

All of the following are in aqueous solution. Which is incorrectly named? H2CO3, carbonic acid HCN, cyanic acid HCl, hydrochloric acid H3PO4, phosphoric acid H2SO4, sulfuric acid

HCN, cyanic acid

If a solution of sodium bicarbonate is mixed with a solution containing an equal number of moles of nitric acid, then sodium nitrate, water, and carbon dioxide are produced. What is the net ionic equation representing the reaction?

HCO3^1-(aq) + H^1+(aq) → H2O(l) + CO2(g)

Which is the strongest acid of the following? HIO HClO2 HClO HBrO

HClO2

Which of the following statements is false?

HClO3 is a weaker acid than H2SO3

Which of the following statements is false? nitrite is a stronger base than nitrate HClO3 is a weaker acid than H2SO3 H2S is a stronger acid than H2O HBrO3 is a stronger acid than HBrO2

HClO3 is a weaker acid than H2SO3

There are six strong acids. Which of the following is not a strong acid?

Which acid is the strongest acid? HNO2 HF HCO2H HC3H5O3

which species are considered to be bronsted-lowry acids

HF and H3O1+ are both Bronsted-Lowry acids because they both donate protons.

Select the stronger acid from each pair: I. HBr, HI II HClO2, HClO3 III H2SO3, HClO3

HI HClO3 HClO3

The following three equations represent equilibria that lie far to the right. HNO3(aq) + CN-(aq) mc003-1.jpg HCN(aq) + NO3-(aq) HCN(aq) + OH-(aq) mc003-2.jpg H2O(l) + CN-(aq) H2O(l) + CH3O-(aq) mc003-3.jpg CH3OH(aq) + OH-(aq) Identify the strongest acid.

HNO3

The following three equations represent equilibria that lie far to the right. HNO3(aq) + CN-(aq) = HCN(aq) + NO3-(aq) HCN(aq) + OH-(aq) = H2O(l) + CN-(aq) H2O(l) + CH3O-(aq) = CH3OH(aq) + OH-(aq) Identify the strongest acid.

HNO3

Which of the following is the correct order for increasing pHs for equimolar solutions of HNO3, KCl, NH4Cl, KOH, and NaC2H3O2? (Ka for HC2H3O2 is 1.80 x 10-5, Ka for NH4+ is 5.56 x 10-10).

HNO3, NH4Cl, KCl, NaC2H3O2, KOH

The hydrogen sulfate or bisulfate ion HSO4- can act as either an acid or a base in water solution. In which of the following equations does HSO4- act as an acid?

HSO4- + H2O ® SO42- + H3O+

The Oxygen in blood is carried by a large iron-containing protein called hemoglobin(Hb)

Have the patient breathe pure oxygen.

Using the information below, which of the following treatments might be highly effective for carbon monoxide poisoning, if started immediately?

Have the patient breathe pure oxygen.

In which of the following groups are the noble gases arranged correctly in order of increasing boiling point?

He, Ne, Kr, Xe

Consider protein structures:

Hydrogen bonds form between adjacent proteins.

Consider protein structures: There are two possible types of secondary structures in protiens...

Hydrogen bonds form between adjacent proteins.

According to the graph below, what chemical was added to the equilibrium mixture and how did the system respond?

Hydrogen was added and the concentration of nitrogen decreased.

If a catalyst was added the values represented by which arrows would change?

I and III only

Which, if any of the following mixtures will result in a precipitate. You might need to know that the Ksp for AgCN is 2.2 ´ 10-16 and that for PbI2 is 7.9 ´ 10-9. I. a mixture that is 1.2 ´ 10-6 M AgNO3 and 2.4 ´ 10-10 M NaCN II. a mixture that is 2.3 ´ 10-4 M Pb(ClO4)2 and 4.6 ´ 10-3 M KI

I will precipitate but II will not precipitate

Which of these salts would have increased solubility in a 0.10 M solution of HNO3, compared with their solubilities in pure water at same temperature?

Mg(OH)2

Which of the following are true at equilibrium for the reaction A==B I. [A] is no longer changing. II. The overall rate of change of [B] is zero. III. No new molecules of A are converting into B. IV. The value of [B]/[A] is changing in time.

I, II

Which of the following result(s) in an increase in the entropy of the system? I. mc004-1.jpg II. Br2(g) ® Br2(l) III. NaBr(s) ® Na+(aq) + Br-(aq) IV. O2(298 K) ® O2(373 K) V. NH3(1 atm, 298 K) ® NH3(3 atm, 298 K)

I, III, IV

Which of the following statements is true? I. The concentration of a pure liquid does not appear in the mass-action expression II. If Q > K, the reaction will produce more products and less reactants to reach equilibrium III. The equilibrium constant of an overall reaction is the product of the equilibrium constants of the individual reactions that add up to the overall reaction IV. If A D B has a reaction quotient, Q, then n A D n B has a reaction quotient, Qn V. An equilibrium constant expressed in terms of concentrations can be greater than the corresponding equilibrium constant expressed in terms of pressure, depending on the reaction

I, III, IV and V

consider the equation cl2 + 2KI

I-

In which of the following reactions do you expect to have the largest increase in entropy?

I2(s) " I2(g)

Which of the following reactions will have a positive value of DS°? I. Pb(s) + Cl2(g) " PbCl2(s) II. 2H2S(g) + 3O2(g) " 2H2O(g) + 2SO2(g) III. K2SO4(s) " 2K+(aq) + SO42-(aq)

III only

When each of the following is heated to 50C and the temperature is held constant for 5 minutes, which one undergoes only a physical change?

Ice cream

Which of the following is endothermic?

Ice cream melts.

Which of these statement provides an accurate comparison of the general properties of solids and liquids?

In a solid, particles are slightly closer together, have greater interparticle attractions, and have lower particle motion compared with a liquid.

If element X whose photoelectron spectrum is shown above bonded with oxygen, what type of bond would be formed and what would be the chemical formula of the resulting compound?

Ionic, Al2O3

Which of the following is true about chemical equilibrium?

It is microscopically dynamic and macroscopically static

The question below refers to the following system: Co(H2O)62+ + 4 Cl- mc010-1.jpg CoCl42- + 6H2O (pink) (blue) When cobalt(II) chloride is added to pure water, the Co2+ ions hydrate. The hydrated form then reacts with the Cl- ions to set up the equilibrium shown here. Which statement below describes the change that the system will undergo if silver nitrate is added?

It should become more pink.

You make a cell with an aluminum electrode in a solution of aluminum nitrate and a zinc electrode in a solution of zinc nitrate. Al3+ + 3e1- → Al(s) E = -1.66 v Zn2+ + 2e1- → Zn(s) E = -0.76 v If you could increase the concentration of Al3+, which of the following is true about the cell potential?

It would Decrease

It would decrease.

You make a cell with an aluminum electrode in a solution of aluminum nitrate and a zinc electrode in a solution of zinc nitrate. You make a cell with an aluminum electrode in a solution of aluminum nitrate and a zinc electrode in a solution of zinc nitrate. If you could increase the concentration of Zn2+, which of the following is true about the cell potential?

It would increase.

Electrolysis of a molten salt with the formula MCl, using a current of 3.86 amp for 16.2 min, deposits 1.52 g of metal. Identify the metal. (1 faraday = 96,485 coulombs)

Identify the element whose photoelectron spectrum is shown below.

The equilibrium mc009-1.jpgis established at -10°C. The equilibrium constant expression is P4 + 6Cl one

K = 1 -------- [P4][Cl2]6

K will be greater than 1.

Which of the following is ionic and containes both sigma and pi bonds?

KCN

The compound most likely to be ionic is

A student dissolved 30 g of an unknown compound in 50 g of water at 39°C. What is the unknown compound?

KNO3

Which species acts exclusively as spectator ions in this reaction?

K^1+ + Pb^2+

Which of the following combination of elements is likely to produce and ionic bond? Li and Cl N and S N and O Li and Rb

Li and Cl

Which pair of elements is likely to produce an ionic bond?

Li and Cl

One way to produce nitric acid is through the Ostwald process. In the first reaction ammonia is oxidized to nitrogen monoxide. mc006-1.jpg Which of the following should shift equilibrium to products?

Lower the temperature of the reaction and remove nitrogen monoxide as it is made.

for a labratory investigation, Identify which substance is being oxidized and which substance is being reduced in this laboratory investigation.

Magnesium is being oxidized, and the hydrogen ion is being reduced.

The question below refers to the following system: Co(H2O)62+ + 4 Cl- mc009-1.jpg CoCl42- + 6H2O (pink) (blue) When cobalt(II) chloride is added to pure water, the Co2+ ions hydrate. The hydrated form then reacts with the Cl- ions to set up the equilibrium shown here. Which statement below describes the change that the system will undergo if water is added?

More chloride ions will be produced.

Solve without using a calculator. A compound of nitrogen and oxygen is 63.64% by mass nitrogen. What is the empirical formula of this compound?

N2O

Which of the following is a conjugate acid/base pair? H3O+/OH- HCl/OCl- NH4+/NH3 H2SO4/SO42-

NH4+/NH3

Which of the following ions is likely to form a soluble sulfate in aqueous solution?

NH41+

The following data were collected for several compounds of nitrogen and oxygen If compound X has an equal number of oxygen and nitrogen atoms, what is the most likely formula for compound Y?

NO2

Which of the following is incorrectly named with the structure next to it? NH4ClO4, ammonium perchlorate Mg(OH)2, magnesium hydroxide NO3-, nitrite ion PO43-, phosphate ion Pb(NO3)2, lead(II) nitrate

NO3-, nitrite ion

Which of the following correctly ranks the species from weakest to strongest base HF HCN HClO2 NH4

NO31- < H2O < CLO21- < F1- < NH3 < CN1-

Which of the following correctly ranks the species from weakest to strongest base? HF (Ka = 7.1x10^-4) HCN (Ka = 6.2x10^-10) HClO2 (Ka = 1.2x10^-2) NH4+ (Ka = 5.6x10^-10)

NO31- < H2O < CLO21- < F1- < NH3 < CN1-

An element X has the ground-state valence electron configuration of ns2np5. The formula for the compound composed of element X and nitrogen is most likely

NX3

Which of the following pairs of ions would not form a solid in aqueous solution?

Na1+ and SO4^2-

Which equation for dissolving this salt in water is written correctly?

Na2SO4 = 2Na^1+ + SO4^2-

Solve without using a calculator. A compound is analyzed and found to contain 1.30 moles of Na, 0.65 moles of Te, and 2.60 moles of O. What is the simplest formula of this compound?

Na2TeO4

Bromothymol blue is a chemical indicator that turns blue at pH values greater than 7. In which of these solutions would a blue color be observed if 2 drops of bromothymol blue were added? The concentration of each solution is 0.10 M. Ka for HC2H3O2(aq) = 1.8 ´ 10-5, Kb for NH3(aq) = 1.8 ´ 10-5

NaC2H3O2

Which of the following correctly labels the salts? HF (Ka = 7.2 ´ 10-4) NH3 (Kb = 1.8 ´ 10-5) HCN (Ka = 6.2 ´ 10-10)

NaCN = basic, NH4F = acidic, KCN = basic

Which of the following substances contains both ionic and covalent bonds?

NaOH

Spectator ions are those that are in solution, but do not react. Identify any spectator ions for the reaction of sodium phosphate with calcium nitrate. Ca^2+(aq) and PO4^3-(aq) Na^1+(aq) and PO4^3-(aq) only PO4^3-(aq) Na^1+(aq) and NO3^1-(aq)

Na^1+(aq) and NO3^1-(aq)

The substances neon, sodium fluoride, carbon monoxide, and methylamine all have low molar masses. Order these substances in increasing boiling points or melting points.

Ne < CO < CH3NH2 < NaF

The photoelectron spectra above show the energy required to remove a 1s electron from a nitrogen atom and from an oxygen atom. Which of the following statements best accounts for the peak in the upper spectrum being to the right of the peak in the lower spectrum?

Nitrogen atoms have a smaller nuclear charge than oxygen atoms.

If 30 mL of 5.0 ´ 10-4 M Ca(NO3)2 are added to 70 mL of 2.0 ´ 10-4 M NaF, will a precipitate occur? (Ksp of CaF2 = 4.0 ´ 10-11)

No, because the ion product is less than Ksp.

You have 100.0 mL of a solution of hydrochloric acid that has a pH of 3.00. You add 100.0 mL of water to this solution. What is the resulting pH of the solution?

None of the above is correct, but the pH must be greater than 3.00.

For a spontaneous exothermic process, which of the following must be true?

None of the three answer choices is correct.

The Lewis structure of carbon dioxde is

O(4dots)=C=O(4dots)

On a cold day near the ocean, it was found that 8 g of an unknown gas occupies a volume that is a little less than 6 L. Based on this information, what is the most likely identity of the unknown gas?

Of the most common ions of the third period elements Mg, Al, P, and S, which is the largest? (Note: ion charges are not shown in the answer choices)

Which of the following is the strongest base? (Kb for NH3 is 1.8 ´ 10-5, Ka2 for H2SO4 is 1.2 ´ 10-2, Ka3 for H3PO4 is 4.8 ´ 10-13) NH3, HSO4-, PO43-, or NO3-

PO43

Consider the phosphoric acid equilibira. What species is predominant at pH 12? *PICTURE NOT INCLUDED

PO43-

A certain element being studied by X-ray photoelectron spectroscopy (PES) displays an emission with five distinct peaks. What is the possible element being studied?

Phosphorus

Equal volumes of equimolar H2S and OH1- are combined. Which diagram represents the resultant solution?

Picture B

Which of the following is true regarding the salt bridge in this voltaic cell?

Potasssium ions travel to the cathode, and nitrate ions travel to the anode.

The reaction Q + R ® R2Q is found to be first order in R2 and zero order in Q. Which of these mechanisms is most likely for this reaction?

R2 ----> 2R

The reaction Q + R ® R2Q is found to be first order in R2 and zero order in Q. Which of these mechanisms is most likely for this reaction?

R2 = 2R(slow) R+Q=RQ(fast) RQ+R=R2Q(fast)

Consider the reaction X ® Y + Z Which of the following is a possible rate law?

Rate = k[X]

In a research project, a scientist adds 0.1 mole of HCN, 0.1 mole of H3O1+, and 0.1 mole of CN1- to water to make a total volume of 1 L. Will this reaction proceed to a greater extent in the forward direction or in the reverse direction?

Reverse; the K value is less than 1.

A gas is found to diffuse at half the rate of methane (CH4). Which of the following could be this gas?

SO2

Which of the species below, when dissolved in H2O, will not produce a basic solution? BaO Ba(OH)2 SO2 NH3

SO2

It is found that the value of the reaction quotient is 12 for a given reaction, whereas the equilibrium constant is 8.0. Which statement best describes how the system will respond?

Since Q > K, the reverse reaction is favored and the equilibrium shifts to the left.

What is the difference between a strong acid and a weak acid?

Strong acids are completely dissociated in solution while weak acids are not.

Which pair of elements is likely to produce a nearly nonpolar covalent bond?

Te and I

Which of the following is the best explanation of how the ions in KCl interact with a polar solvent in the process of dissolution?

The K1+ ions are attracted to the negative end of the polar solvent, and the Cl1- ions are attracted to the positive end.

Solid sodium chloride was added to pure water slowly, with stirring, at 25°C until no more sodium chloried would dissolve. Solid remained on the bottom of the container, even after the solution was stirred repeatedly over 8 hours. After the solid was allowed to settle, some of the clear, colorless solution was carefully poured off into a flask. This flask was placed in a refrigerator at a temperature of 4°C for 2 hours. When the flask was removed from the refrigerator, a small amount of white solid was found to have appeared in the flask. What is the best explanation for this?

The Ksp of NaCl decreases with decreasing temperature.

Ten grams of Ca(OH)2(s) is added, with stirring, to 100 mL of water, producing a saturated solution with solid Ca(OH)2on the bottom of the beaker. Which is true?

The addition of 0.1 mole of solid Ca(NO3)2 will cause some additional Ca(OH)2 to form.

An example of an alloy is shown in the diagram below. Compared with the pure metal X, how would you expect the properties of the alloy to vary?

The alloy has lower malleability and higher density.

Consider the gas phase reaction NO + mc005-1.jpgO2 mc005-2.jpg NO2 for which DH° = -56.91 kJ and K =1.46 ´ 106 at 25°C. For this system at equilibrium, how will raising the temperature affect the amount of NO present?

The amount of NO will increase.

Consider two samples of a gas in identical rigid containers, Sample A at 273 K and Sample B at 300 K. Which of the following statements is true? Solve without using a calculator.

The average kinetic energy of Sample A is less than that of Sampe B.

Consider the following data for the dissolution of an alcohol, R-OH, in a solvent, X-OH. DH1 = 65 kJ/mol, DH2 = 340 kJ/mol, DH3 = -8 kJ/mol. Predict and explain the solubility of this compound. Do this without a calculator.

The compound would not be soluble because DHsoln = 397 kJ/mol, which is very endothermic.

As water is heated, its pH decreases. This means that:

The dissociation of water is an endothermic process.

Which of the following is true for the cell shown here? Zn(s) | Zn2+(aq) || Cr3+(aq) | Cr(s)

The electrons flow from the zinc to the chromium.

The acid strength of the oxyacids of chlorine is as follows: HClO4 > HClO3 > HClO2 > HClO Which statement best explains this trend?

The electrons in the H-O bond are pulled away from the hydrogen by the more electronegative oxygen, making the bond weaker. Additional oxygen atoms intensify this effect, making the H-O bond even weaker and increasing the degree of ionization.

he acid strength of the oxyacids of chlorine is as follows: mc006-1.jpg Which statement best explains this trend?

A reaction takes place within a system. As a result, the entropy of the system decreases. Which of the following statements must be true?

The entropy of the surroundings increases.

Which of the following statements is true?

The equilibrium state is dynamic even though there is no change in concentrations.

The melting points of the compounds LiF, NaCl, KBr, and CsI exhibit the following trend: Melting point order: LiF > NaCl > KBr > CsI. Which of the following correctly explains this trend?

The greater radii of the larger ions results in smaller lattice energies, leading to lower melting points.

In general, the value of the equilibrium constant for a chemical reaction does NOT depend on

The initial amounts of reactants present.

The reactivity of the alkali metals increases going down the group. Which is the correct explanation for this trend?

The ionization energy decreases as you move down the group, thus it requires less energy to remove the valence electron and results in greater reactivity.

A 20.0 g sample of a hydrated compound is placed into a crucible and heated. The data table for this laboratory investigation is shown below. Why can we conclude that all of the water of hydration has been removed? Solve without using a calculator.

The mass of the crucible and sample remained relatively constant after the second heating.

The fact that metals are conductive is best explained by which of the following statements?

The metal nuclei reside in a "sea" of delocalized electrons

Which of the following reactions is possible at the anode of a galvanic cell?

Zn→ Zn2+ + 2e-

Aqueous solutions of NaCl and Na2CrO4 are mixed and they do not react. To this mixture an aqueous solution of AgNO3 is added (dropwise). At first, a white solid forms. As the AgNO3 solution continues to be added, a yellow solid begins to form. AgCl(s) is white in color and Ag2CrO4(s) is yellow. Which of the following is the most accurate conclusion based on these results?

The molar solubility of AgCl is less than the molar solubility of Ag2CrO4 because the white solid formed first.

Which of the following statements is true concerning real gases?

The observed pressure will be less than the ideal pressure, and the volume available for the gas particles is less than the volume of the container.

The graph below shows the number of molecules that have sufficient energy to overcome Ea for a given reaction. How would adding an enzyme change the appearance of the graph?

The one where exactly half of it is dark.

Based on molecular structure and intermolecular forces, which of these substances would you predict to have the greatest viscosity?

The one with 3 OH's on the bottom

Which particulate model represents copper(II) carbonate?

The one with only 4 thingys (triangle with 3 circles and one of the circles has a square on top of it)

Below are the photoelectronA researcher needs to prepare a pH 5 buffer. What solutions would be best? spectra of the the electrons in the second energy level for nitrogen and oxygen. Based on the spectra below, which of the following best explains the difference in binding energy of the electrons in nitrogen and oxygen?

The oxygens in the 2s orbital have higher binding energy because oxygen has more protons while oxygen's 2p electrons have a lower binding energy due to greater electron-electron repulsion.

The autoionization of water, as represented by the below equation, is known to be endothermic. Which of the following correctly states what occurs as the temperature of water is raised? H2O(l) + H2O(l) = H3O+(aq) + OH-(aq)

The pH of the water decreases, and the water remains neutral.

How would diluting HA from 0.15 M to 0.005 M affect the pH of the solution?

The pH would increase because the [H1+] decreases.

Solve without using a calculator. A sample of neon gas is contained in the left-hand bulb and a sample of helium gas is contained in the right-hand bulb of a two-bulb container connected by a valve, as shown in the diagram. Initially the valve is closed.

The partial pressure of neon is 1.50 times as great as the partial pressure of helium

What will happen if a small amount of hydrochloric acid is added to a 0.1 M solution of HF?

The percent ionization of HF will decrease.

What will happen if a small amount of sodium hydroxide is added to a 0.1 M solution of ammonia?

The percent ionization of ammonia will decrease.

A certain mass of neon gas is contained in a rigid steel container. The same mass of helium gas is added to this container. Which of the following best describes what happens? Assume the temperature is contant.

The pressure in the container more than doubles.

The process involves coupling a very thermodynamically favorable reaction with one that is not thermodynamically favorable

Which of the following occurs after the addition of O2?

The rate of the forward reaction increases, and the value of K remains the same.

The rate law of a reaction is determined to be rate = k[A][B]2 . Which statement would most likely describe this reaction?

The reaction involves the formation of intermediates.

Alcohols are organic compounds containing a hydroxyl (-OH) group. WHen a solution containing dichromate ions is added to most alcohols, chromium(III) iions are formed. The color of the sooution changes from bright orange to green. mc003-1.jpg In the kinetic study, the natural logarithms of the absorbance values were plotted versus time, resulting in a straight line. What does this indicate about the order of the reaction with respect to the dichromate ion?

The reaction is first order in dichromate.

For a particular chemical reaction DH = 4.3 kJ and DS =-19 J/K. Under what temperature condition is the reaction spontaneous?

The reaction is not spontaneous at any temperature.

A mixture of hydrogen and chlorine remains unreacted until it is exposed to ultraviolet light from a burning magnesium strip. Then the following reaction occurs very rapidly: H2(g) + Cl2(g) ® 2HCl(g) DG = -45.54 kJ DH = -44.12 kJ DS = -4.76 J/K Which of the following is consistent with this information?

The reaction is spontaneous, but the reactants are kinetically stable.

Solutions A and B are both clear and colorless. When Solution A is mixed with Solution B, the temperature of the mixture increases, and a yellow precipitate is observed. What can be concluded from these observations?

The reaction is thermodynamically favored (spontaneous) only at low temperatures

Under normal conditions, an iron nail rusts so slowly that the recation is not easily observed. What must be true?

The reaction occurs, but very slowly.

Which of the following statements is FALSE?

The reaction of O3(g) to produce O2(g) has a negative entropy change.

For the reaction, X + Y " A + B, DGo is -1324 kJ. Which one of the following statements is NOT valid concerning the reaction?

The reaction will proceed rapidly from left to right.

An esterification reaction occurs when an alcohol reacts with a carboxylic acid as shown below. The equilibrium constant is approximately 5 at room temperature, but the rate of reaction without a catalyst is very slow. How do the rates of the forward and reverse reactions compare at equilibirum?

The reverse rate is the same as the forward rate.

A correct representation of an ionic solid could be described as having

positive and negative ions in fixed positions in a framework.

The mineral fluorite is the main source of calcium fluoride. CaF2 has a solubility of 2.2 ´ 10-4 M in pure water. Which is a correct explanation for what occurs when solid CaF2 is dissolved in an acidic solution, rather than in pure water?

The solubility increases because HF is a weak acid.

Predict what effect increasing the charge of the metal ion has on the solubility in water of KCl compared with CaCl2.

The solubility of KCl is greater than that of CaCl2 due to weaker Coulombic forces in the KCl.

Which of the following describes what happens to the solubility of a slightly soluble ionic compound when a common ion is added to the solution?

The solubility of the ionic compound is reduced.

The equilibrium constant for the ionization of hypochlorous acid is 2.0 x 10-8. If a 1.0 M solution is at pH 2, what is the equilibrium condition of the system? HClO + H2O ↔ H3O1+ + ClO1-

The system will shift to the left to make reactants.

For the equilibrium system: CO2(g) + H2(g) mc013-1.jpg CO(g) + H2O(g) mc013-2.jpgH = +42 kJ/mol K equals 1.6 at 1260 K. If 0.15 mol each of CO2, H2, CO, and H2O (all at 1260 K) were placed in a 1.0-L thermally insulated vessel that was also at 1260 K, then as the system came to equilibrium:

The temperature would decrease and the mass of CO2 would decrease

Which statement correctly describes what happens to the volume?

The volume increases by a factor of less than 2.

You are asked to make a 1.00L of a solution buffered at ph of 9

The volume of the 1.00 M HCN must be greater than the volume of the 1.00 M NaCN.

A strip of copper is placed in a 1 M solution of copper nitrate and a strip of silver is placed in a 1 M solution of silver nitrate. The two metal strips are connected to a voltmeter by wires and a salt bridge connects the solutions. The following standard reduction potentials apply: Ag+(aq) + e- ® Ag(s) e° = +0.80 V Cu2+(aq) + 2e- ® Cu(s) e° = +0.34 V Which of the following statements is false?

There is a net general movement of silver ions through the salt bridge to the copper half-cell.

Consider the chemical system CO + Cl2 mc015-1.jpg COCl2; K = 4.6 x 109 L/mol. How do the equilibrium concentrations of the reactants compare to the equilibrium concentration of the product?

They are much smaller.

Which of the following best describes BF3 and NF3? (Note: Geometry refers to the electron pair arrangement, and shape refers to the atom arrangement.)

They have different geometry and different shapes.

For the process S8 (rhombic) ® S8 (monoclinic) at 110°C, DH = 3.21 kJ/mol and DS = 8.70 J/K × mol (at 110°C). Which of the following is correct?

This reaction is spontaneous at 110°C (S8 (monoclinic) is stable).

Fossil Fuels

Trees absorb carbon dioxide and use the carbon to grow.

A 0.10 M HCl solution may be titrated with two different bases: 0.10 M NaOH or 0.10 M Ca(OH2). Which statement best describes the volumes of the bases necessary to reach the equivalence point?

Twice as much NaOH is needed.

Consider the following electrode potentials: Mg2+ + 2e- ® Mg e° = -2.37 V V2+ + 2e- ® V e° = -1.19 V Cu2+ + e- ® Cu+ e° = 0.16 V Which one of the reactions below will proceed spontaneously from left to right?

V + 2Cu2+ ® V2+ + 2Cu+

Using Hess' law and the equations below find ΔH° at 25°C for the oxidation of C2H5OH(l)

W - Y

Using Hess' law and the equations below find ΔH° at 25°C for the oxidation of C2H5OH(l).

W - Y

The physical properties of four unkown pure substances were determined in a laboratory. Based on the information given in the table below, which correctly identifies the type of element or compound?

W = ionic, X = covalent network; Y = molecular; Z = metallic

The table below shows the first eight ionization energies for 4 random elements from the second and third periods of the periodic table. Based on these data, which elements would most likely have similar chemical properties?

W and X

At the normal body temperature of a human, 37°C, the equilibrium constant for the dissociation of water is higher than it is at 25°C, as shown in the equilibrium expression. What is true of pure water at 37°C? *PICTURE OF EQN NOT INCLUDED

Water is neutral because the hydrogen and hydroxide ion concentrations are equal.

At the normal body temperature of a human, 37°C, the equilibrium constant for the dissociation of water is higher than it is at 25°C, as shown in the equilibrium expression. mc005-1.jpg What is true of pure water at 37°C?

Water is neutral because the hydrogen and hydroxide ion concentrations are equal.

Why do mineral deposits accumulate on the heating coil of a water distiller?

When the water vaporizes, soluble salts precipitate out.

Which of the following statements concerning equilibrium is TRUE?

When two opposing processes proceed at the same rate, the system is at equilibrium

Solve without using a calculator. The simplest formula for a compound made from element X (molar mass = 79.0 g/mol) that is 21.0% nitrogen by mass is

X2N3

The simplest formula for a compound made from X (molar mass = 79.0 g/mol) that is 21.0% nitrogen by mass is

X2N3

The table shows the first ionization energies of element X in kJ/mol. What is the most likely formula of the compound between element X and Y, where Y is a halogen?

XY2

Consider this system: 3.5 ´ 102 mL of 3.2 M Pb(NO3)2 and 2.0 ´ 102 mL of 0.020 M NaCl are added together. Ksp for the lead chloride is 1.6 ´ 10-5. Will precipitation occur?

Yes

Iron can be protected from oxidation by putting it into electrical contact with a substance that is more likely to be oxidized than iron. Given the reduction potentials below, which metals could be used to protect iron? (Do without a calculator). Fe2+(aq) + 2e- = Fe(s)

Zn or Mg

For which of the following can we directly compare their Ksp values to determine their relative solubilities?

ZnS and AgI

A solution with initial concerntrations of 6.00 M Fe3+ and 10.0 M SCN1- is allowed to reach equilibrium. At equilibrium it is found that the concentration of FeSCN2+ is 4.00 M. What are the equilibrium concentrations of the Fe3+ and SCN1-? Do without a using a calculator.

[Fe+3]= 2.00M and [SCN-]=6.00M

The sodium salt, NaA, of a weak acid is dissolved in water; no other substance is added. Which of these statements (to a close approximation) is true?

[HA] = [OH-]

A 0.10 mol NaC2H3O2 and 0.050 mol HCl was added to 1.0 L of 0.075 M HC2H3O2. List the species in order of decreasing equilibirum concentration.

[HC2H3O2] > [C2H3O21-] > [Cl1-] > [H3O1+]

In the reaction 3W + X = 2Y + Z, all substances are gases. The recation is initiated by adding an equal number of moles of W and X. When equilibrium is reached,

[X] > [W]

Which of the following shows an increase in entropy?

a burning piece of wood

A substance with strong intermolecular forces of attraction would be expected to have

a high heat of vaporization.

A substance is found to be nonconductive, to have a relatively low melting point, and to be insolublein water. This is most likely

a molecular solid.

A small amount of copper is added to silver to form sterling silver. This is

a solution formation, with silver as the solvent and copper as the solute.

In which process is DS expected to be positive?

a spontaneous endothermic process at a constant temperature and pressure

Which item (a, b or c) in each of the three groups below has the lowest entropy? I. (a) 10 g ice (b) 10 g water vapor (c) 10 g liquid water II. (a) 1 mole NaCl solid (b) 1 mol NaCl in 1 M aqueous solution (c) 1 mol molten NaCl III. (a) 1 mole C2H6(g), (b) 1 mole CH4(g), (c) 1 mol C3H8(g) all at 25 °C and 1 atm

a, a, b

Select the answer that best describes an aqueous solution made from each of the following substances: solid aluminum chloride (AlCl3)

acidic

Select the answer that best describes an aqueous solution made from each of the following substances: solid ammonium perchlorate (NH4ClO4) For NH4+, Ka = 5.6 x 10-10; for ClO4-, Kb » 10-21.

acidic

Which of the following name(s) is(are) correct? 1. sulfide, S2- 2. ammonium chloride, NH4Cl 3. acetic acid, HC2H3O2 4. barium oxide, BaO

all

The type of bonding in a solid can be tested by placing the substance in water because

all of these are true.

Which of the following names is incorrect? cobalt(II) chloride

aluminum(III) oxide

Which of these correctly matche the molecular compound with the most important force between molecules of the same substance?

ammonia: hydrogen bonding

As you go down the noble gas family on the periodic table, the boiling temperature increases. This trend is due mainly to

an increase in London dispersion forces.

The reaction mc003-1.jpg has an enthalpy of change of -92 kJ. Increasing the temperature of this equilibrium system causes

an increase in [N2]

Which of the following changes to the system at equilibrium would result in an increase in the concentration of O2?

an increase in the concentration of SO3 and an increase in the temperature

In the titration of a weak acid HA with 0.100 M NaOH, the stoichiometric point is known to occur at a pH value of approximately 11. Which of the following indicators would be best to use to mark the endpoint of this titration?

an indicator with Ka = 10-12

Refer to the galvanic cell below (the contents of each half-cell are written beneath each compartment): mc003-1.jpg 0.10 M MnO4- 0.40 M Cr3+ 0.20 M Mn2+ 0.30 M Cr2O72- 0.010 M H+ 0.010 M H+ The standard reduction potentials are as follows: MnO4- + 8H+ + 5e- ® Mn2+ + 4H2O, e° = 1.51 V Cr2O72- + 14H+ + 6e- ® 2Cr3+ + 7H2O, e° = 1.33 V In which direction do electrons flow in the external circuit?

anode to cathode

Peak A is far to the left of peaks B, C and D in the spectrum. The BEST explanation for this is that the electrons corresponding to peak A

are the innermost electrons in the atom and experience the least shielding

Describe the pH of the following salts? NaF, NH4Cl, KI, NH4F

basic, acidic, neutral, cannot tell without further information

Over time, a solution of ethanol in water left open to the atmosphere

becomes less concentrated because ethanol is more volatile than water.

A solution is prepared by mixing 500 mL of 1 M HCl with 500 mL of 0.01 M HNO3. What is the pH of the solution? Do this without a calculator.

between 0.0 and 1.0.

Bismuth-214 is a radioactive isotope that may decay into polonium-214 or into thallium-210. Which isotope would have the most similar chemical reactivity to bismuth-214?

bismuth-210

Electrolysis of water is a chemical change because

bonds between H atoms and O atoms in individual molecules are broken.

CaCl2

calcium chloride

A student attempted to dissolve a liquid ionic solute in a nonpolar solvent. The resulting mixture showed three distinct layers. This would be classified as a

chemical change because three distinct layers were formed.

For which process is DS negative?

compressing 1 mol Ne at constant temperature from 1.5 L to 0.5 L

Two gases are removed from their original container and placed into a third container, where they react with each other. All three containers have identical volumes and all gasses are at the same temperature.

container B before the reaction

Glass for electronic devices needs to be more durable than typical window glass. Sodium ions on the glass surface are replaed by larger ions when the glass is dipped into a molten salt. Which type of salt would give the toughest glass?

potassium

Graphite and diamond are network solids, but graphite is slippery, black, and a conductor, while diamond is hard, colorless, and an insulator. This is because

diamond is made up of tetrahedrally bonded carbon atoms, while graphite is made up of fused six-membered rings arranged in sheets.

Nitrogen and oxygen can combine in many different proportions to create different compounds. Which compound has a N:O mass ratio of 7:20. Do this without a calculator, but you may use a periodic table.

dinitrogen pentoxide

When a polar molecule dissolves in water, the solute-solvent interaction is

either hydrogen bonding or dipole-dipole force

Based on the experimental data given in the table, what is the order of the reaction with respect to A? Do this without a calculator.

first

What is the major factor that accounts for most of the difference in the two values?

forces of attraction between chlorine molecules

In which of the following isothermal expansions of an ideal gas is the work done by the system the largest? Assume the temperature is the same for all choices.

from 1 to 10 L against an opposing pressure of 2 atm

At a certain temperature C(s) + O2 ® CO2(g) has a DG of -339.4 kJ/mol. This means that at this temperature

gaseous carbon dioxide spontaneously forms.

The pH of a 1.0 M sodium acetate solution is:

greater than 7.0

In column chromatography (e.g., with Sep-Pak cartridges used in a liquid chromatography lab), the first substance eluted

has a high affinity for the mobile phase.

Classify the contents in the graduated cylinder after the 5 minutes has elapsed.

homogeneous mixture

Increasing the pressure on a gas in a rigid container at constant temperature will

increase the influence of intermolecular attractions because the molecules will be closer together

In the titration of a weak acid, HA, with a sodium hydroxide solution of approximately the same concentration, the stoichiometric point occurs at pH = 9.5. Which of the following weak acid indicators would be best suited to mark the endpoint of this titration?

indicator A, Ka = 10-11

Iodine crystals dissolve in hexane more readily than in wter. However, if the iodine crystals are left in the water for an extended time period, they will dissolve at the interface. This can be best explained because

iodine, although nonpolar in nature, has momentary dipoles that can interact with the polar water molecules.

When an ionic salt dissolves in water, the solute-solvent interaction is

ion-dipole forces

The properties of solids vary with their bonding. An example of this is shown by

ionic solids with strong electrostatic attractions called ionic bonds, which have high melting temperatures.

What is the correct name for Fe2S3?

iron(III) sulfide

1-Butanol (CH3CH2CH2CH2OH) would be expected to have a higher boiling temperature than 1-propanol (CH3CH2CH2OH) because

its longer carbon chain and greater number of electrons result in more London dispersion forces.

When two elements form a series of compounds, the rations of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers. This is known as

law of multiple proportions

The correct name for LiCl is

lithium chloride

Unde what conditions does a gasbehave more like a real gas than an ideal gas?

low temperature and high pressure

What conditions would maximize the yield in the reaction for the formation of xenon tetrafluoride?

low temperature, high pressure

In which of the following electron transitions for a hydrogen atom does the light emitted have the longest wavelength? (No calculations needed to answer this question)

n = 4 to n = 3

Radioactive decay displays first-order kinetics. If the decay of iodine-131 is measured over time, which of these graphs will show a straight line?

natural logarithm of mass of 131I versus time

Which of the following statements is false?

nitrite is a stronger base than nitrate

What is the name of an aqueous solution that constains HNO2?

nitrous acid

In which of the following pairs is the substance with the HIGHER entropy listed first? I. NaCl(s), NaCl(aq) II. CO(g), CO2(g) III. 1 mole of H2(g) at 25°C; 1 mole of H2(g) at 50°C

none of them

In which of the following pairs is the substance with the HIGHER entropy listed first? I. NaCl(s), NaCl(aq) II. CO(g), CO2(g) III. 1 mole of H2(g) at 25°C; 1 mole of H2(g) at 50°C

none of them

In which reaction is DS° expected to be positive?

none of these

For the reaction of sodium bromide with chlorine gas to form sodium chloride and bromine, the appropriate half-reactions are (ox = oxidation and re = reduction):

ox: 2Br- ® Br2 + 2e-; re: Cl2 + 2e- ® 2Cl-

The autoionization of water is an endothermic process. How would the pH of pure water change if the water was at 100°C?

pH would decrease because equilibrium shifts towards [H3O1+] and [OH1-].

Which of the following pairs is incorrect? phosphorus pentoxide, P2O5 All of the above pairs are correct. sulfur hexafluoride, SF6 ammonia, NH3 iodine trichloride, ICl3

phosphorus pentoxide, P2O5

The four compounds shown all exhibit intermolecular hydrogen bonding. Which one of these compounds can also form intramolecular hydrogen bonds?

picture with N+

The type of bonding within a water molecule is

polar covalent bonding.

What rate law is supporte by this mechanizm?

rate = k[W2]

Non polar solutes dissolve more readily in nonpolar solvents than polar solvents because

the induced dipole of the solute molecule creates an induced dipole in the solvent molecule and London dispersion forces occur.

Two salts, AX and BX2, have identical Ksp values at a given temperature. We can say

the molar solubility of AX is greater than that of BX2.

Copper is produced by the smelting of copper(I) oxide: Cu2O(s) ¶ 2 Cu(s) + 1/2 O2(g). However, this reaction is not thermodynamically favorable at easily obtained temperatures, DG = 140 kJ at 375 K. When carbon is included with the copper(I) oxide, however, the reaction becomes favorable. This is because

the oxidation of carbon has a sufficiently negative value of DG that it can drive the unfavorable reaction.

At a certain temperature, the synthesis of ammonia gas from nitrogen and hydrogen gases, shown as mc005-1.jpg, has a value for K of 3.0 x 10-2. If [H2]o = [N2]o = 0.10 M and [NH3]o = 0.20 M,

the reaction would shift toward the N2 and the H2.

Small drops of water tend to bead up because of

the resistance to increased surface area.

The values for the change in enthalpy, DH, and the activation energy, Ea, for a given reaction are known. The value of Ea for the reverse reaction equals

the sum of -DH and Ea.

A buffer can maintain pH upon addition of small amounts of a strong base because

the weak acid reacts with the strong base to make more conjugate base.

Assume an indicator works best when the equivalence point of a titration comes in the middle of the indicator range. Which indicator would be best for the following titration? 0.100 M HOCl (Ka = 3.5 ´ 10-8) + 0.100 M NaOH

thymolphthalein (9.5 - 10.5)

A visible light spectrophotometer would best be used in which of these situations?

to determine the concentration of a solution of copper(II) nitrate

The function of a salt bridge (or porous barrier) in an electrochemical cell (galvanic cell) is to allow ions to flow

to keep the net charge on each side at zero.

The predicted molecular shape of PH3 according to the VSEPR theory is

trigonal pyramidal

The hydrogen halides (HF, HCl, HBr, and HI) are all polar molecules. The strength of the acid each forms in water is based on which of the following? two of these the size of the molecule the strength of the bond the polarity of the molecule

two of these

Several liquids are compared by adding them to a series of 50-mL graduated cylinders, then dropping a steel ball of uniform size and mass into each. The time required for the ball to reach the bottom of the cylinder is noted. This is a method used to compare the differences in a property of liquids kown as

viscosity.

Consider the dissociation of hydrogen: H2(g) = 2H(g) One would expect that this reaction: (note: at equilibrium)

will be spontaneous at high temperatures

Consider the dissociation of hydrogen: H2(g) mc010-1.jpg 2H(g) One would expect that this reaction:

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