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