Question 1

The heat of neutralization of HCl by NaOH is $\Delta$H°rxn = -56.2 kJ/mol. How much heat is released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?

Accepted Answer

7.31 kJ

Question 2

The heat of hydration ($\Delta$Hhydr)of ions is always endothermic.

Accepted Answer

A) True 
 B)False  False

Question 3

Aluminum oxide can be reduced to aluminum metal using carbon, the other reaction product being carbon monoxide. Determine the enthalpy change when 12.5 g of aluminum is produced by this method.[$\Delta$H°f(carbon monoxide)= -110.5 kJ/mol; $\Delta$H°f(aluminum oxide)= -1669.8 kJ/mol]

Accepted Answer

A) 725 kJ 
B) 697 kJ 
C) 310 kJ 
D) 361 kJ 
E) 1504 kJ 
A) 725 kJ 
B) 697 kJ 
C) 310 kJ 
D) 361 kJ 
E) 1504 kJ C

Question 4

The specific heat of gold is 0.129 J/g·°C. What is the molar heat capacity of gold?

Accepted Answer

A) 0.039 J/mol·°C 
B) 0.129 J/mol·°C 
C) 25.4 J/mol·°C 
D) 39.0 kJ/mol·°C 
E) 197 J/mol·°C 
A) 0.039 J/mol·°C 
B) 0.129 J/mol·°C 
C) 25.4 J/mol·°C 
D) 39.0 kJ/mol·°C 
E) 197 J/mol·°C

Question 5

When 0.560 g of Na(s)reacts with excess F2(g)to form NaF(s), 13.8 kJ of heat is evolved at standard-state conditions. What is the standard enthalpy of formation ($\Delta$H°f)of NaF(s)?

Accepted Answer

A) 24.8 kJ/mol 
B) 570 kJ/mol 
C) -24.8 kJ/mol 
D) -7.8 kJ/mol 
E) -570 kJ/mol 
A) 24.8 kJ/mol 
B) 570 kJ/mol 
C) -24.8 kJ/mol 
D) -7.8 kJ/mol 
E) -570 kJ/mol

Question 6

Solid sodium peroxide (Na2O2)reacts with liquid water yielding aqueous sodium hydroxide and oxygen gas. How much heat is released when 250.0 L of oxygen gas is produced from the reaction of sodium peroxide and water if the reaction is carried out in an open container at 1.000 atm pressure and 25°C? (Given: $\Delta$H°f[Na2O2(s)] = -510.9 kJ/mol; $\Delta$H°f[NaOH(aq)] = -469.2 kJ/mol; $\Delta$H°f[H2O(l)] = -285.8 kJ/mol)

Accepted Answer

A) 35,400 kJ 
B) 1740 kJ 
C) 141.7 kJ 
D) 3330 kJ 
E) 2900 kJ 
A) 35,400 kJ 
B) 1740 kJ 
C) 141.7 kJ 
D) 3330 kJ 
E) 2900 kJ

Question 7

When 18.5 g of HgO(s)is decomposed to form Hg(l)and O2(g), 7.75 kJ of heat is absorbed at standard-state conditions. What is the standard enthalpy of formation ($\Delta$H°f)of HgO(s)?

Accepted Answer

A) -90.7 kJ/mol 
B) -7.75 kJ/mol 
C) 0.419 kJ/mol 
D) 27.9 kJ/mol 
E) 143 kJ/mol 
A) -90.7 kJ/mol 
B) -7.75 kJ/mol 
C) 0.419 kJ/mol 
D) 27.9 kJ/mol 
E) 143 kJ/mol

Question 8

The combustion of octane produces heat according to the equation 2C8H18(l)+ 25O2(g)$\rarr$16CO2(g)+ 18H2O(l)$\Delta$H°rxn= -11,020 kJ/mol
What is the heat of combustion per gram of octane?

Accepted Answer

A) -5,510 kJ/g 
B) -96.5 kJ/g 
C) -48.2 kJ/g 
D) -193 kJ/g 
E) -6.292 * 105 kJ/g 
A) -5,510 kJ/g 
B) -96.5 kJ/g 
C) -48.2 kJ/g 
D) -193 kJ/g 
E) -6.292 * 105 kJ/g

Question 9

The heat of solution of LiCl is -37.1 kJ/mol, and the lattice energy of LiCl(s)is 828 kJ/mol.Calculate the total heat of hydration of 1 mol of gas phase Li+ ions and Cl- ions.

Accepted Answer

A) 791 kJ 
B) 865 kJ 
C) -865 kJ 
D) -791 kJ 
E) None of these. 
A) 791 kJ 
B) 865 kJ 
C) -865 kJ 
D) -791 kJ 
E) None of these.

Question 10

The specific heats of water and iron are 4.184 and 0.444 J/g°C, respectively. When equal masses of water and iron both absorb the same amount of heat, the temperature increase of the water will be 5.42 times greater than that of the iron.

Accepted Answer

A) True 
 B)False

Question 11

A 0.3423 g sample of pentane, C5H12, was burned in a bomb calorimeter. The temperature of the calorimeter and the 1.000 kg of water contained therein rose from 20.22°C to 22.82°C. The heat capacity of the calorimeter is 2.21 kJ/°C.The heat capacity of water = 4.184 J/g·°C. What is the heat of combustion, in kilojoules, per gram of pentane?

Accepted Answer

Question 12

How many degrees of temperature rise will occur when a 25.0 g block of aluminum absorbs 10.0 kJ of heat? The specific heat of Al is 0.900 J/g·°C.

Accepted Answer

A) 0.44°C 
B) 22.5°C 
C) 225°C 
D) 360°C 
E) 444°C 
A) 0.44°C 
B) 22.5°C 
C) 225°C 
D) 360°C 
E) 444°C

Question 13

Calcium oxide and water react in an exothermic reaction: CaO(s)+ H2O(l)$\rarr$Ca(OH)2(s)$\Delta$H°rxn = -64.8 kJ/mol
How much heat would be liberated when 7.15 g CaO(s)is dropped into a beaker containing 152g H2O?

Accepted Answer

A) 1.97 * 10-3 kJ 
B) 8.26 kJ 
C) 508 kJ 
D) 547 kJ 
E) 555 kJ 
A) 1.97 * 10-3 kJ 
B) 8.26 kJ 
C) 508 kJ 
D) 547 kJ 
E) 555 kJ

Question 14

Find the heat absorbed from the surroundings when 15 g of O2 reacts according to the equation O + O2 $\rarr$ O3, $\Delta$H°rxn= -103 kJ/mol.

Accepted Answer

A) 4.6 * 10-3 kJ 
B) 48 kJ 
C) 96 kJ 
D) 32 kJ 
E) 110 kJ 
A) 4.6 * 10-3 kJ 
B) 48 kJ 
C) 96 kJ 
D) 32 kJ 
E) 110 kJ

Question 15

The work done on the surroundings by the expansion of a gas is w = -P$\Delta$V.

Accepted Answer

A) True 
 B)False

Question 16

Chemical energy is

Accepted Answer

A) the energy stored within the structural units of chemical substances. 
B) the energy associated with the random motion of atoms and molecules. 
C) solar energy, i.e.energy that comes from the sun. 
D) energy available by virtue of an object's position. 
A) the energy stored within the structural units of chemical substances. 
B) the energy associated with the random motion of atoms and molecules. 
C) solar energy, i.e.energy that comes from the sun. 
D) energy available by virtue of an object's position.

Question 17

A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter. The total heat capacity of the calorimeter plus water was 5,760 J/°C. If the temperature rise of the calorimeter with water was 0.570°C, calculate the enthalpy of combustion of magnesium. Mg(s)+ 1/2O2(g)$\rarr$ MgO(s)

Accepted Answer

A) -3280 kJ/mol 
B) -24.8 kJ/mol 
C) 435 kJ/mol 
D) 106 kJ/mol 
E) -602 kJ/mol 
A) -3280 kJ/mol 
B) -24.8 kJ/mol 
C) 435 kJ/mol 
D) 106 kJ/mol 
E) -602 kJ/mol

Question 18

Pentaborane B5H9(s)burns vigorously in O2 to give B2O3(s)and H2O(l).Calculate $\Delta$H°rxn for the combustion of 1 mol of B5H9. $\Delta$H°f[B2O3(s)] = -1,273.5 kJ/mol
$\Delta$H°f[B5H9(s)] = 73.2 kJ/mol
$\Delta$H°f[H2O(l)] = -285.8 kJ/mol

Accepted Answer

A) -1,2735 kJ/mol 
B) -4,543 kJ/mol 
C) -18,170 kJ/mol 
D) -9,086 kJ/mol 
E) -8,448 kJ/mol 
A) -1,2735 kJ/mol 
B) -4,543 kJ/mol 
C) -18,170 kJ/mol 
D) -9,086 kJ/mol 
E) -8,448 kJ/mol

Question 19

Heat is

Accepted Answer

A) a measure of temperature. 
B) a measure of the change in temperature. 
C) a measure of thermal energy. 
D) a measure of thermal energy transferred between two bodies at different temperature. 
A) a measure of temperature. 
B) a measure of the change in temperature. 
C) a measure of thermal energy. 
D) a measure of thermal energy transferred between two bodies at different temperature.

Question 20

The value of $\Delta$H°rxn for the following reaction is -6535 kJ/mol.
2C6H6(l)+ 15O2(g)$\rarr$12CO2(g)+ 6H2O(g)
How many kilojoules of heat will be evolved during the combustion of 16.0 g of C6H6(l)?

Accepted Answer

The answer of The value of $\Delta$H°rxn for the following...

Exam 6: Thermo-Chemistry

The heat of neutralization of HCl by NaOH is Δ\DeltaΔ H°rxn = -56.2 kJ/mol. How much heat is released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?

The heat of hydration ( Δ\DeltaΔ Hhydr)of ions is always endothermic.

Aluminum oxide can be reduced to aluminum metal using carbon, the other reaction product being carbon monoxide. Determine the enthalpy change when 12.5 g of aluminum is produced by this method.[ Δ\DeltaΔ H°f(carbon monoxide)= -110.5 kJ/mol; Δ\DeltaΔ H°f(aluminum oxide)= -1669.8 kJ/mol]

The specific heat of gold is 0.129 J/g·°C. What is the molar heat capacity of gold?

When 0.560 g of Na(s)reacts with excess F2(g)to form NaF(s), 13.8 kJ of heat is evolved at standard-state conditions. What is the standard enthalpy of formation ( Δ\DeltaΔ H°f)of NaF(s)?

When 18.5 g of HgO(s)is decomposed to form Hg(l)and O2(g), 7.75 kJ of heat is absorbed at standard-state conditions. What is the standard enthalpy of formation ( Δ\DeltaΔ H°f)of HgO(s)?

The combustion of octane produces heat according to the equation 2C8H18(l)+ 25O2(g) →\rarr→ 16CO2(g)+ 18H2O(l) Δ\DeltaΔ H°rxn= -11,020 kJ/mol What is the heat of combustion per gram of octane?

The heat of solution of LiCl is -37.1 kJ/mol, and the lattice energy of LiCl(s)is 828 kJ/mol.Calculate the total heat of hydration of 1 mol of gas phase Li+ ions and Cl- ions.

The specific heats of water and iron are 4.184 and 0.444 J/g°C, respectively. When equal masses of water and iron both absorb the same amount of heat, the temperature increase of the water will be 5.42 times greater than that of the iron.

How many degrees of temperature rise will occur when a 25.0 g block of aluminum absorbs 10.0 kJ of heat? The specific heat of Al is 0.900 J/g·°C.

Calcium oxide and water react in an exothermic reaction: CaO(s)+ H2O(l) →\rarr→ Ca(OH)2(s) Δ\DeltaΔ H°rxn = -64.8 kJ/mol How much heat would be liberated when 7.15 g CaO(s)is dropped into a beaker containing 152g H2O?

Find the heat absorbed from the surroundings when 15 g of O2 reacts according to the equation O + O2 →\rarr→ O3, Δ\DeltaΔ H°rxn= -103 kJ/mol.

The work done on the surroundings by the expansion of a gas is w = -P Δ\DeltaΔ V.

Chemical energy is

A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter. The total heat capacity of the calorimeter plus water was 5,760 J/°C. If the temperature rise of the calorimeter with water was 0.570°C, calculate the enthalpy of combustion of magnesium. Mg(s)+ 1/2O2(g) →\rarr→ MgO(s)

Pentaborane B5H9(s)burns vigorously in O2 to give B2O3(s)and H2O(l).Calculate Δ\DeltaΔ H°rxn for the combustion of 1 mol of B5H9. Δ\DeltaΔ H°f[B2O3(s)] = -1,273.5 kJ/mol Δ\DeltaΔ H°f[B5H9(s)] = 73.2 kJ/mol Δ\DeltaΔ H°f[H2O(l)] = -285.8 kJ/mol

Heat is

The value of Δ\DeltaΔ H°rxn for the following reaction is -6535 kJ/mol. 2C6H6(l)+ 15O2(g) →\rarr→ 12CO2(g)+ 6H2O(g) How many kilojoules of heat will be evolved during the combustion of 16.0 g of C6H6(l)?

Chemistry: The Study of Change

Atoms, Molecules, and Ions

Mass Relationships in Chemical Reactions

Reactions in Aqueous Solution

Gases

Quantum Theory and the Electronic Structure of Atoms

Periodic Relationships Among the Elements

Chemical Bonding I: Basic Concepts

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Chemistry in the Atmosphere

Entropy, Free Energy, and Equilibrium

Electrochemistry

Metallurgy and the Chemistry of Metals

Nonmetallic Elements and Their Compounds

Transition Metal Chemistry and Coordination Compounds

Nuclear Chemistry

Organic Chemistry

Synthetic and Natural Organic Polymers

Filters

The heat of neutralization of HCl by NaOH is $\Delta$ H°_rxn = -56.2 kJ/mol. How much heat is released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?

The heat of hydration ( $\Delta$ H_hydr)of ions is always endothermic.

Aluminum oxide can be reduced to aluminum metal using carbon, the other reaction product being carbon monoxide. Determine the enthalpy change when 12.5 g of aluminum is produced by this method.[ $\Delta$ H°_f(carbon monoxide)= -110.5 kJ/mol; $\Delta$ H°_f(aluminum oxide)= -1669.8 kJ/mol]

When 0.560 g of Na(s)reacts with excess F₂(g)to form NaF(s), 13.8 kJ of heat is evolved at standard-state conditions. What is the standard enthalpy of formation ( $\Delta$ H°_f)of NaF(s)?

When 18.5 g of HgO(s)is decomposed to form Hg(l)and O₂(g), 7.75 kJ of heat is absorbed at standard-state conditions. What is the standard enthalpy of formation ( $\Delta$ H°_f)of HgO(s)?

The combustion of octane produces heat according to the equation 2C₈H₁₈(l)+ 25O₂(g) $\rarr$ 16CO₂(g)+ 18H₂O(l) $\Delta$ H°_rxn= -11,020 kJ/mol What is the heat of combustion per gram of octane?

The heat of solution of LiCl is -37.1 kJ/mol, and the lattice energy of LiCl(s)is 828 kJ/mol.Calculate the total heat of hydration of 1 mol of gas phase Li⁺ ions and Cl^- ions.

Calcium oxide and water react in an exothermic reaction: CaO(s)+ H₂O(l) $\rarr$ Ca(OH)₂(s) $\Delta$ H°_rxn = -64.8 kJ/mol How much heat would be liberated when 7.15 g CaO(s)is dropped into a beaker containing 152g H₂O?

Find the heat absorbed from the surroundings when 15 g of O₂ reacts according to the equation O + O₂ $\rarr$ O₃, $\Delta$ H°_rxn= -103 kJ/mol.

The work done on the surroundings by the expansion of a gas is w = -P $\Delta$ V.

A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter. The total heat capacity of the calorimeter plus water was 5,760 J/°C. If the temperature rise of the calorimeter with water was 0.570°C, calculate the enthalpy of combustion of magnesium. Mg(s)+ 1/2O₂(g) $\rarr$ MgO(s)

Pentaborane B₅H₉(s)burns vigorously in O₂ to give B₂O₃(s)and H₂O(l).Calculate $\Delta$ H°_rxn for the combustion of 1 mol of B₅H₉. $\Delta$ H°_f[B₂O₃(s)] = -1,273.5 kJ/mol $\Delta$ H°_f[B₅H₉(s)] = 73.2 kJ/mol $\Delta$ H°_f[H₂O(l)] = -285.8 kJ/mol

The value of $\Delta$ H°_rxn for the following reaction is -6535 kJ/mol. 2C₆H₆(l)+ 15O₂(g) $\rarr$ 12CO₂(g)+ 6H₂O(g) How many kilojoules of heat will be evolved during the combustion of 16.0 g of C₆H₆(l)?