Chemistry

Ethyl alcohol is produced by the fermentation of glucose, C6H12O6. C6H12O6(s) → 2 C2H5OH(l) + 2 CO2(g) ΔH∘ = -69.1 kJ Given that the enthalpy of formation is -277.7 kJ/mol for C2H5OH(l) and -393.5 kJ/mol for CO2(g), find the enthalpy of formation for C6H12O6.

-1273.3 kJ/mol

When 1.50 mol of CH4(g) reacts with excess Cl2(g) at constant pressure according to the chemical equation shown below, 1062 kJ of heat are released. Calculate the value of ΔH for this reaction, as written. 2 CH4(g) + 3 Cl2(g) → 2 CHCl3(l) + 3 H2(g) ΔH = ?

-1420 kJ

The values ofΔH∘ f for the three states of benzene are approximately -22 kcal/mol, -11 kcal/mol, and 20 kcal/mol. Which is the value for solid benzene?

-22 kcal/mol

Acetylene torches utilize the following reaction: 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g) Use the given standard enthalpies of formation to calculate ΔH∘ for this reaction.

-2512.4 kJ

Calculate the enthalpy of combustion per mole for C6H12O6. Assume that the combustion products are CO2(g) and H2O(l).

-2816 kJ/mol

Calculate the work energy, w, gained or lost by the system when a gas expands from 15 L to 35 L against a constant external pressure of 1.5 atm. [1 L ⋅ atm = 101 J]

-3.0 kJ

Calculate the work, w, gained or lost by the system when a gas expands from 15 L to 35 L against a constant external pressure of 1.5 atm. 1 L ⋅ atm = 101 J

-3.0 kJ

At constant pressure, the combustion of 10.0 g of C2H6(g) releases 518 kJ of heat. What is ΔH for the reaction given below? 2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(l)

-3120 kJ

One method for making ethanol, C2H5OH, involves the gas-phase hydration of ethylene, C2H4: Estimate ΔH for this reaction from the given average bond dissociation energies, D.

-35 kJ

Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the chemical equation shown below. When 0.015 mol of Na is added to 100.00 g of water, the temperature of the resulting solution rises from 25.00°C to 31.45°C. If the specific heat of the solution is 4.18 J/(g ⋅°C), calculate ΔH for the reaction, as written. 2 Na(s) + 2 H2O(l) → 2 NaOH(aq) + H2(g) ΔH = ?

-360 kJ

When 1.50 g of Ba(s) is added to 100.00 g of water in a container open to the atmosphere, the reaction shown below occurs and the temperature of the resulting solution rises from 22.00°C to 33.10°C. If the specific heat of the solution is 4.18 J/(g ⋅°C), calculate ΔH for the reaction, as written.

-431 kJ

Use the given standard enthalpies of formation to calculate ΔH∘ for the following reaction 3 Fe2O3(s) + CO(g) → 2 Fe3O4(s) + CO2(g).

-47.2 kJ

Find ΔE° for the reaction below if the process is carried out at a constant pressure of 1.00 atm and ΔV (the volume change) = -24.5 L. (1 L ⋅ atm = 101 J) 2 CO(g) + O2 (g) → 2 CO2(g) ΔH° = -566. kJ

-564 kJ

When 10.00 moles of H2(g) reacts with 5.000 mol of O2(g) to form 10.00 mol of H2O(l) at 25°C and a constant pressure of 1.00 atm. If 683.0 kJ of heat are released during this reaction, and PΔV is equal to -37.00 kJ, then

-683.0 kJ and ΔE∘ = -646.0 kJ.

Use the given average bond dissociation energies, D, to estimate ΔH for the reaction of methane, CH4(g), with fluorine according to the equation: CH4(g) + 2 F2(g) → CF4(g) + 2 H2(g)

-716 kJ

Given: S (s) + O2 (g) → SO2 (g) ΔH∘ = -296.1 kJ 2 SO3 (g) → 2 SO2 (g) + O2 (g) ΔH∘ = 198.2 kJ Find ΔH∘ for : 2 S(s) + 3 O2(g) → 2 SO3(g)

-790.4 kJ

It takes 11.2 kJ of energy to raise the temperature of 145 g of benzene from 24.0°C to 69.0°C. What is the specific heat of benzene?

1.72 J/(g ⋅ °C)

It takes 11.2 kJ of energy to raise the temperature of 145 g of benzene from 25.0°C to 70.0°C. What is the specific heat of benzene?

1.72 J/(g ⋅ °C)

How much heat is absorbed when 30.00 g of C(s) reacts in the presence of excess SO2(g) to produce CS2(l) and CO(g) according to the following chemical equation? 5 C(s) + 2 SO2(g) → CS2(l) + 4 CO(g) ΔH∘ = +239.9 kJ

119.9 kJ

The heat of vaporization of water at 100°C is 40.66 kJ/mol. Calculate the quantity of heat that is absorbed/released when 6.00 g of steam condenses to liquid water at 100°C.

13.5 kJ of heat are released.

How much heat is absorbed when 35.00 g of C(s) reacts in the presence of excess SO2(g) to produce CS2(l) and CO(g) according to the following chemical equation? 5 C(s) + 2 SO2(g) → CS2(l) + 4 CO(g) ΔH∘ = 239.9 kJ

139.8 kJ

Coal gasification can be represented by the equation: 2 C(s) + 2 H2O(g) → CH4(g) + CO2(g) ΔH = ? Use the following information to find ΔH for the reaction above. CO(g) + H2(g) → C(s) + H2O(g) ΔH = -131 kJ CO(g) + H2O(g) → CO2(g) + H2(g) ΔH = -41 kJ CO(g) + 3 H2(g) → CH4(g) + H2O(g) ΔH = -206 kJ

15 kJ

At 1 atm pressure, the heat of sublimation of gallium is 277 kJ/mol and the heat of vaporization is 271 kJ/mol. To the correct number of significant figures, how much heat is required to melt 3.50 mol of gallium at 1 atm pressure?

21 kJ

When 50.0 mL of 0.400 M Ca(NO3)2 is added to 50.0 mL of 0.800 M NaF, CaF2 precipitates, as shown in the net ionic equation below. The initial temperature of both solutions is 22.0°C. Assuming that the reaction goes to completion, and that the resulting solution has a mass of 100.00 g and a specific heat of 4.18 J/(g ⋅ °C), calculate the final temperature of the solution. Ca2+(aq) + 2 F-(aq) → CaF2(s) ΔH∘ = -11.5 kJ

22.55 C

Find ΔH for BaCO3 (s) → BaO (s)+ CO2 (g) given 2 Ba (s) + O2 (g) → 2 BaO (s) ΔH = -1107.0 kJ Ba (s) + CO2 (g) + 1/2 O2 (g) → BaCO3 (s) ΔH = -822.5 kJ

269.0 kJ

At 25°C the heat of fusion of aluminum is 10.6 kJ/mol and the heat of sublimation is 326.4 kJ/mol. What is the heat of vaporization of aluminum at 25°C?

315.8 kJ/mol

How much heat is absorbed/released when 20.00 g of NH3(g) reacts in the presence of excess O2(g) to produce NO(g) and H2O(l) according to the following chemical equation? 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(l) ΔH∘ = +1168 kJ

342.9 kJ of heat are absorbed.

The specific heat of copper is 0.385 J/(g ⋅ °C). If 34.2 g of copper, initially at 23.0°C, absorbs 4.689 kJ, what will be the final temperature of the copper?

379 C

For the reaction: A + 2 B → 3 C, ΔH∘ = -203 kJ. For the reaction 6 C → 2 A + 4 B, ΔH∘ = ________ kJ.

406

In the reaction shown below, ________ kJ of heat are released per mole of O2(g) that reacts. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) ΔH = -2045 kJ

409 kJ

How much heat is transferred per mole of NH3(g) formed in the reaction shown below? N2(g) + 3 H2(g) → 2 NH3(g) ΔH∘ = - 92.2 kJ

46.1 kJ

For a process at constant pressure, 12,400 calories of heat are released. This quantity of heat is equivalent to

5.19 × 104 J.

For a system at constant pressure, 12,400 calories of heat are released. This quantity of heat is equivalent to

5.19 × 104 J.

Given: 4 NO2(g) + O2(g) → 2 N2O5(g) ΔH∘ = -110.2 kJ find ΔH∘ for N2O5(g) → 2 NO2(g) + 1/2 O2(g).

55.1 kJ

At a constant pressure of 1.50 atm what is the enthalpy change ΔH for a reaction where the internal energy change ΔE is 58.0 kJ and the volume increase is 12.6 L? (1 L·atm = 101.325 J.)

59.9 kJ

How much heat is absorbed/released when 35.00 g of NH3(g) reacts in the presence of excess O2(g) to produce NO(g) and H2O(l) according to the following chemical equation? 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(l) ΔH∘ = 1168 kJ

600.1 kJ of heat are absorbed.

Given that ΔH∘ = -311 kJ for the hydrogenation of acetylene, C2H2: H-CΞC-H(g) + 2 H2(g) → CH3-CH3(g) and the following bond dissociation energies, estimate a value for the C-to-C triple bond dissociation energy.

807 kJ/mol

At 1 atm pressure the heat of sublimation of gallium is 277 kJ/mol and the heat of vaporization is 271 kJ/mol. How much heat is required to melt 1.50 mol of gallium at 1 atm pressure?

9 kJ

Which equation represents the reaction whose ΔH, represents the standard enthalpy of formation of CHCl3(l) at 25°C? (i.e., for which isΔH = ΔH∘f of CHCl3)

C(s) + 1/2 H2(g) + 3/2 Cl2(g) → CHCl3(l)

Which is the most exothermic reaction?

CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l)

Which is a measure of the sum of the kinetic and potential energies of each particle in the system?

E, the internal energy

In the reaction below, is energy released or absorbed by the system? What is the sign of the energy change, E? 432 kJ + A + 2B → 3C

Energy is absorbed. The sign of the energy is positive.

At 298 K the average kinetic energy is the same for H2, He, and N2. The gas with the highest average velocity is

H2

The enthalpy of fusion, or heat of fusion (ΔH fusion), of water is positive and corresponds to which physical change?

H2O(s) → H2O(l)

For which should the standard heat of formation ΔH∘ f, be zero at 25°C? For which should the standard heat of formation f, be zero at 25°C? O(g) O2(g) O3(g) all the above

O2(g)

Under thermodynamic standard state conditions the element oxygen occurs as

O2(g)

What is expected when the reaction shown below takes place in a thermally-insulated container outfitted with a movable piston at a constant atmospheric pressure of 1 atm? 2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(g)

Volume will increase and work will be done by the system.

10.0 g of a metal, initially at 25°C, are placed into 10.0 g of water, initially at 100°C. Which metal will have the highest final temperature? Shown after each metal is its specific heat in J/(g ⋅ °C).

gold (0.129)

The first law of thermodynamics

is a statement of conservation of energy.

The SI unit for energy is the ________.

joule

Energy can be classified as either ________ energy (energy of motion) or ________ energy (stored energy).

kinetic,potential

A reaction for which ΔE = -450 kJ is one in which products have 450 kJ ________ internal energy than the reactants, and products are ________ stable than the reactants.

less,more

When 1.0 mole of MgSO4 is dissolved in water contained in a calorimeter, the temperature of the water and dissolved ions increases. Therefore the sign of ΔH for this reaction is ________, heat is transferred ________ the system ________ the surroundings, and the reaction is classified as ________.

negative,from,to,exothermic

A reaction is performed in a water bath initially at 21°C which decreases to 18°C by the end of the reaction. For this reaction the sign of heat transfer is ________, and the reaction is classified as ________.

positive,endothermic

Water has an unusually high

specific heat

Which of the following is not a type of energy or energy transfer?

temperature

For most chemical reactions

the difference between ΔH and ΔE is very small.

A process is carried out at constant pressure. Given that ΔE is positive and ΔH is negative,

the system loses heat and contracts during the process.

An ideal gas expands into a vacuum (external pressure = 0) without gaining or losing heat. For this expansion

Δ E does not change.

In which case is the work done on the system always positive?

Δ V < 0

For a particular process that is carried out at constant pressure, q = 125 kJ and w = -15 kJ. Therefore,

ΔE = 110 kJ and ΔH = 125 kJ.

For a particular process that is carried out at constant pressure, q = 135 kJ and w = -25 kJ. Therefore,

ΔE = 110 kJ and ΔH = 135 kJ.

When 1.00 mol of benzene is vaporized at a constant pressure of 1.00 atm and at its normal boiling point of 80.1°C, 33.9 kJ are absorbed and PΔV for the vaporization process is equal to 2.90 kJ, then

ΔE = 31.0 kJ andΔH = 33.9 kJ.

For the reaction I2(g) → I2(s), ΔH ° = -62.4 kJ at 25°C. Based on these data, at 25°C

ΔH ° sub = 62.4 kJ/mol.