Chemistry Final Esker

1.41

If helium effuses through a porous barrier at a rate of 4.0 moles per minute, at what rate (in moles per minute) would oxygen gas diffuse?

5

If the [H3O+] of a solution is 1.0 E -9 what is the pOH?

hydroxide ions increase by a factor of 10.

If the pH of a solution changes from 10 to 11.

0.75 atm

If the solubility of a gas in water is 4.0 g/L when the pressure of the gas above the water is 3.0 atm, what is the

Cl2 is reduced and Mg is oxidized.

In the reaction Cl2 (g) + Mg (s) --> MgCl2 (s),

reaction with oxygen.

Originally, the term oxidation meant

F2 < CO2 < NH2CH3

Place the following compounds in order of increasing strength of intermolecular forces. CO2 F2 NH2CH3

2.7 atm

To increase the solubility of a gas at constant temperature from 1.20 g/L, at 1.4 atm, to 2.3 g/L, the pressure would have to be increased to ____.

-335 kJ

Use the information provided to determine ΔH°rxn for the following reaction:

-117 kJ

Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction: 2 NO(g) +O2(g) → 2 NO2(g) ΔH°rxn = ? Given: 1/2 N2(g) + O2(g) → NO2(g) N2(g) + O2(g) → 2 NO(g) ΔH°rxn = +33 kJ ΔH°rxn = +183 kJ

[Mg2+] = 1.2 x 10 -3 M; [F-] = 2.3 x 10 -3 M

What are the equilibrium concentrations of dissolved ions in a saturated solution of MgF2 at 25 oC? Ksp for MgF2 is 6.4 x 10 -9 at 25 oC

The reaction is endothermic.

What do you know about a chemical reaction if the value of DeltaH is positive?

2.29 oC

What is the boiling point elevation when 31.5 g of menthol (C10H20O) is dissolved in 258 g of acetic acid? Kb for acetic acid is 2.93 C/m. Boiling point of acetic acid is 118 oC.

100.26 oC

What is the boiling point of a solution of 0.1 mole of glucose in 200 mL of water? (Kf = 0.512 oC/m)

101.5 oC

What is the boiling point of a solution that contains 3 moles of KBr in 2000 g of water? (Kf = 0.512 oC/m; molar mass of water = 18 g)

B: oC

What is the freezing point of a solution of 0.5 mol of LiBr in 500 mL of water? (Kf = 1.86 oC/m)

3.55 × 10-4 M

What is the hydronium ion concentration of an acid rain sample that has a pH of 3.45?

1 x 10-10

What is the hydroxide ion concentration of a solution with a pH of 4?

0.67m

What is the molality of a solution containing 8.0 grams of solute in 0.50 kg of solvent? (molar mass of solute = 24g)

2 x M

What is the molar solubility in water of PbI2? (The Ksp for PbI2 is 3.2 ×

2 x 10−3 M

What is the molar solubility in water of PbI2? (The Ksp for PbI2 is 3.2 × 10−8)

8.29 M

What is the molarity of the solution produced when 14.1 g of ammonia (NH3) is dissolved in sufficient water to prepare 0.100 L of solution?

0.375

What is the mole fraction of ethanol in a solution of 3.00 moles of ethanol and 5.00 moles of water?

0.145

What is the mole fraction of oxygen in a mixture that contains 66.8 g of oxygen, 44.1 g of nitrogen, and 21.5 g of hydrogen?

72

What is the molecular weight of a pure gaseous compound having a density of 4.95 g/L at -35 oC and 1020 torr?

0.24 kg

What is the number of kilograms of solvent in a 0.70 molal solution containing 5.0 grams of solute? (molar mass of solute = 30 g)

0.1 mol

What is the number of moles of solute in 250 mL of a 0.4M solution?

2.27

What is the pH of a 0.15 M solution of formic acid, HCOOH? Ka= 1.9E-4

0.33 cal/goC

What is the specific heat of a substance if 1560 cal are required to raise the temperature of a 312-g sample by 15oC?

216.8 kJ released per mole

What is the standard heat of reaction for the following reaction? Zn(s) + Cu2+(aq) --> Zn2+(aq) + Cu(s)

1.66 atm

What is the total pressure in a 6.00-L flask which contains 0.127 mol of H2(g) and 0.288 mol of N2(g) at 20.0°C?

86.7 g

What mass of NO2 is contained in a 13.0 L tank at 4.58 atm and 385 K?

34.2 g

What mass of sucrose, C12H22O11, is needed to make 500.0 mL of a 0.200M solution?

4.1 atm

What pressure (in atm) will 0.44 moles of CO2 exert in a 2.6 L container at 25°C?

26 atm

What pressure (in atm) would be exerted by 76 g of fluorine gas in a 1.50 liter vessel at -37oC?

46.6 atm

What pressure would a gas mixture in a 10.0 L tank exert if it were composed of 48.5 g He and 94.6 g CO2 at 398 K?

17.5 L

What volume will 0.780 moles of He occupy at STP?

2 kJ

When 10 g of diethyl ether is converted to vapor at its boiling point, about how much heat is absorbed?

5.24L

When 14.0 g of zinc metal reacts with excess HCl, how many liters of H2 gas are produced at STP?

1.77 J/goC

When 45 g of an alloy, at 25oC, are dropped into 100.0 g of water, the alloy absorbs 956 J of heat. If the final temperature of the alloy is 37oC, what is its specific heat?

2 NO(g) + O2(g) → 2 NO2(g)

Which of the following processes shows a decrease in entropy of the system?

XY (s) <-- X+ (aq) + Y- (aq)

Which of the following represents a precipitation process?

10.0 g Au, CAu = 0.128 J/g°C

Which of the following substances (with specific heat capacity provided) would show the greatest temperature

The volume of a gas's particles is small compared to the overall volume of the gas.

Why is a gas easier to compress than a liquid or a solid?

5.0 x 10-6

A 0.20 M solution of the hypothetical weak acid HZ is found to have a [H+] of exactly 1 x 10-3. The ionization constant, Ka, of the acid HZ is:

Cl2

A 0.334 g sample of an unknown halogen occupies 109 mL at 398 K and 1.41 atm. What is the identity of the halogen?

38.0 g/mol

A 0.465 g sample of an unknown compound occupies 245 mL at 298 K and 1.22 atm. What is the molar mass of the unknown compound?

-7100 kJ

A 1.0 gram sample of sucrose (C12H22O11) is burned in a calorimeter containing 1500 grams of water. The temperature of the water rises from 25 oC to 28.3 oC. Calculate deltaH for the combustion of 1 mol of sucrose.

18.5 kPa

A breathing mixture used by deep-sea divers contains helium, oxygen, and carbon dioxide. What is the partial pressure of oxygen at 101.4 kPa if PHe = 82.5 kPa and PCO2 = 0.4 kPa?

0.222 g

A container with volume 71.9 mL contains water vapor at a pressure of 10.4 atm and a temperature of 465oC. How many grams of the gas are in the container?

1.51 kg

A sample of copper absorbs 43.6 kJ of heat, resulting in a temperature rise of 75.0 °C, determine the mass (in kg) of the copper sample if the specific heat capacity of copper is 0.385 J/g°C.

269oC

A sample of nitrogen occupies 5.50 liters under a pressure of 900 torr at 25oC. At what temperature will it occupy 10.0 liters at the same pressure?

80.2 L

A sample of oxygen occupies 47.2 liters under a pressure of 1240 torr at 25oC. What volume would it occupy at 25oC if the pressure were decreased to 730 torr?

0.064 atm

Calculate P [NO]eq, if P [NOCl]eq = 0.33 atm, P [Cl2]eq = 0.50 atm, and Kp = 1.9 x 10-2. NO(g) + Cl2(g)

48.0 kcal

Calculate the energy released when 24.8 g NaO reacts in the following reaction. NaO(s) + 2HI(g) 2NaI(s) + HO(l) H = -120.00 kcal

0.415 m

Calculate the molality of a solution formed by dissolving 27.8 g of LiI in 500.0 mL of water.

10.59

Calculate the pOH of a solution that contains 3.9 x 10-4 M H3O at 25°C.

64.0 K

Calculate the temperature, in K, of 2.20 moles of gas occupying 3.50 L at 3.30 atm.

0.016 M

Calculate the value of [N2]eq if [H2]eq = 2.0 M, [NH3]eq = 0.5 M, and Kc = 2.

0.062 M

Calculate the value of [N2]eq if [H2]eq = 2.0 M, [NH3]eq = 0.5 M, and Kc = 2.

178.3 kJ

Calculate the value of deltaH for the reaction CaCO3 --> CO2 + CaO from the following enthalpy changes:

number of solute particles in a solution.

Colligative properties depend upon the ____

concentration of solute molecules dissolved.

Colligative properties of solutions depend on the

0.83 atm

Consider the following reaction: 0.56 atm CO2 and 0.32 atm CO. Determine the equilibrium pressure of CO if Kp for the reaction at this temperature is 2.25.

0.037 M

Consider the following reaction: COCl2. Determine the equilibrium concentration of CO if Kc for the reaction at this temperature is 8.33 × 10-4. Calculate this based on the assumption that the answer is negligible compared to 1.6 (ignore X).

0.12 M

Consider the following reaction: initially contains 2.8 M H2O and 2.6 M SO2. Determine the equilibrium concentration of H2S if Kc for the reaction at this temperature is 1.3 × 10-6.

0.322 M

If 12.0 mL of 1.34 M NaOH is required to neutralize 25.00 mL of a sulfuric acid, H2SO4, solution, what is the molarity of the sulfuric acid?

2.0 × 10-5

Determine the Kb for CN at 25°C. The Ka for HCN is 4.9 × 10-10.

8.8 × 10-5 M

Determine the [H3O ] in a 0.265 M HClO solution. The Ka of HClO is 2.9 × 10-8.

0.232 M

Determine the [OH-] concentration of a 0.116 M Ba(OH)2 solution at 25°C.

1.35 × 10-4 M

Determine the molar solubility of PbSO4 in pure water. Ksp (PbSO4) = 1.82 × 10-8.

2.26

Determine the pH of a 0.461 M HC6H5CO2 M solution if the Ka of HC6H5CO2 is 6.5 x 10-5.

2.0 × 10-37

Determine the value of Kc for the following reaction if the equilibrium concentrations are as follows:

2.8 × 1020

Determine the value of Kp for the following reaction if the equilibrium concentrations are as follows:

8.6 L

If a sample of 0.29 moles of Ar occupies 3.8 L under certain conditions, what volume will 0.66 moles occupy under the same conditions?

+5.8 kJ

Estimate G°rxn for the following reaction at 449.0 K.

-72.9 kJ

Estimate ΔG°rxn for the following reaction at 387 K

Oxidation occurs when oxidation number increases, and reduction occurs when oxidation number decreases.

How do oxidation and reduction relate to changes in oxidation number?

50 mL

How many mL of a 2.0M NaBr solution are needed to make 200.0 mL of 0.50M NaBr?

769 kJ

How much energy is evolved during the reaction of 48.7 g of Al, according to the reaction below? Assume that excess Fe2O3

600.1 kJ of heat are absorbed.

How much heat is absorbed/released when 35.00 g of NH3(g) reacts in the presence of excess O2(g) to produce

none of these

How much will the freezing point of 1050 g of benzene be lowered if 31.1 g of orcinol (C7H802) is dissolved in the benzene? Kf for benzene is 5.12 C/m.

1.0 x 10-18 M

The Ksp of nickel sulfide (NiS) is 4.0 x 10-20. What is the concentration of sulfide ion in a saturated solution of nickel sulfide to which 0.040 mol of nickel nitrate (NiNO3) is added?

2.0 x 10-10 M

The Ksp of nickel sulfide (NiS) is 4.0 x 10-20. What is the concentration of sulfide ion in a saturated solution of nickel sulfide?

3.0 × 10-3

The concentration of iodide ions in a saturated solution of lead (II) iodide is _____ M. The solubility product constant of PbI2 is 1.4 × 10-8.

+1

The oxidation number of hydrogen when it is in a compound other than a hydride is ____.

3.16 E -11

The pH of a 0.10 M solution of HA is 5.75. What is Ka for HA?

end point.

The point at which an indicator changes color during a titration is called the

3.6 × 10-2

The reaction below has a Kc value of 61. What is the value of Kp for this reaction at 500 K?

specific heat and mass of the substance.

The size of a temperature increase in a substance depends primarily upon the

4.3 × 10-14

The solubility of manganese (II) hydroxide (Mn(OH)2) is 2.2 × 10-5 M. What is the Ksp of Mn(OH) 2?

2.62 J

The specific heat of silver is 0.24 J/goC. How many joules of energy are needed to warm 4.37 g of silver from 25.0oC to 27.5oC?

281 mL

The volume of 6.80M HCl needed to make 319 mL of 6.00M HCl is ____.

5.18 L

The volume of a sample of nitrogen is 6.00 liters at 35oC and 740 torr. What volume will it occupy at STP?

0.18M

To 225 mL of a 0.80M solution of KI, a student adds enough water to make 1.0 L of a more dilute KI solution. What is the molarity of the new solution?

Which of the following processes have a S > 0?

sodium chloride dissolves in pure water