Question 1

Two solutions (the system),each of 25.0 mL volume and at 25.0°C,are mixed in a beaker.A reaction occurs between them,and the temperature rises to 35.0°C.After the products have equilibrated with the surroundings,the temperature is again 25.0°C and the total volume is 50.0 mL.No gases are involved in the reaction.Which one of the following relationships concerning the change from initial to final states (both at 25.0°C)is correct?

Accepted Answer

E

Question 2

Cold packs,whose temperatures are lowered when ammonium nitrate dissolves in water,are carried by athletic trainers when transporting ice is not possible.Which of the following is true of this reaction?

Accepted Answer

D

Question 3

A system that does no work but which receives heat from the surroundings has

Accepted Answer

C

Question 4

A system initially has an internal energy E of 501 J.It undergoes a process during which it releases 111 J of heat energy to the surroundings,and does work of 222 J.What is the final energy of the system,in J?

Accepted Answer

The final energy of the system can be calculated using the first law of thermodynamics: ΔE = Q - W. Here, ΔE is the change in internal energy, Q is the heat exchanged, and W is the work done by the system. The system releases 111 J of heat (Q = -111 J) and does 222 J of work (W = 222 J). So, ΔE = -111 J - 222 J = -333 J. The final energy is 501 J - 333 J = 168 J.

Question 5

Your favorite candy bar,Gummy Beakers,contains 1.2 $\times$ 10⁶ J of energy while your favorite soft drink,Bolt,contains 6.7 $\times$ 10⁵ J.If you eat two packs of Gummy Beakers a day and drink 3 cans of Bolt,what percent of your 2000 Calorie daily food intake is left for broccoli,beans,beef,etc.?

Accepted Answer

First, we need to convert the energy in the candy bars and soft drink from joules to Calories. 
1.2 x 10^10 J = 2866.18 Calories (rounded to two decimal places)
6.7 x 10^10 J = 16019.05 Calories (rounded to two decimal places)

Next, we need to calculate the total Calories consumed from the candy bars and soft drink in a day. 
2 packs of Gummy Beakers = 2 x 2866.18 Calories = 5732.36 Calories 
3 cans of Bolt = 3 x 16019.05 Calories = 48057.15 Calories 
Total Calories consumed = 5732.36 + 48057.15 = 53789.51 Calories

To find the percent of the daily food intake left for other foods, we subtract the total Calories consumed from 2000 Calories (the daily food intake). 
2000 Calories - 53789.51 Calories = -51789.51 Calories

Since we cannot have negative Calories, this means that we have exceeded our daily food intake and there is no percent left for other foods. Therefore, the answer is B) 47%.

Question 6

Natural gas,or methane,is an important fuel.Combustion of one mole of methane releases 802.3 kilojoules of energy.How much energy does that represent in kilocalories?

Accepted Answer

1 kilocalorie is equivalent to 4.184 kilojoules. Therefore, 802.3 kilojoules is equal to 802.3 / 4.184 = 191.8 kilocalories, which is approximately 1.92 x 10^2 kcal.

Question 7

A system contracts from an initial volume of 15.0 L to a final volume of 10.0 L under a constant external pressure of 0.800 atm.The value of w,in J,is

Accepted Answer

The work done by the system is given by the formula:
w = -PΔV
where P is the external pressure and ΔV is the change in volume.
Here, P = 0.800 atm, ΔV = (final volume - initial volume) = (10.0 L - 15.0 L) = -5.0 L.
Substituting these values in the formula, we get:
w = -0.800 atm x (-5.0 L) x 101.325 J/L atm
w = 405 J (rounded to 3 significant figures)
Since the system is contracting (i.e., volume is decreasing), the work done by the system will be negative. Therefore, the answer is option D, -405 J.

Question 8

A system receives 575 J of heat and delivers 425 J of work.Calculate the change in the internal energy,$\Delta$E,of the system.

Accepted Answer

The change in internal energy (ΔE) is calculated using the first law of thermodynamics: ΔE = Q - W, where Q is the heat added to the system and W is the work done by the system. Here, ΔE = 575 J - 425 J = 150 J.

Question 9

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm.
The work (w)done by the system,in J,is

Accepted Answer

The work done by the system is given by the formula w = -PΔV, where P is the external pressure and ΔV is the change in volume. Plugging in the given values, we get w = -1.00 atm x (2.00 L - 1.00 L) x (101.3 J/L•atm) = 1.01 x 10^2 J = 1.01 x 10^2 J = 1.01 x 10^2 J, which corresponds to choice C.

Question 10

A system which undergoes an adiabatic change and has work done on it by the surroundings has

Accepted Answer

The answer of A system which undergoes an adiabatic change...

Question 11

The dissolution of barium hydroxide in water is an exothermic process.Which of the following statements is correct?

Accepted Answer

The dissolution of barium hydroxide in water is an exothermic process, which means that heat is released. Therefore, the enthalpy of the solution is lower than the enthalpy of the solid barium hydroxide and water before they are mixed. This is because some of the energy stored in the solid and liquid is released as heat during the dissolution process. Consequently, Choice B is correct: the enthalpy of solid barium hydroxide plus pure water is greater than that of the solution, at the same temperature.

Question 12

Which of the following is not a state function?

Accepted Answer

State functions are properties that depend only on the current state of the system and not on the path taken to reach that state. Internal energy, volume, pressure, and enthalpy are all state functions. Work, on the other hand, is not a state function because the amount of work done depends on the path taken to reach the current state.

Question 13

An ideal gas (the system)is contained in a flexible balloon at a pressure of 1 atm and is initially at a temperature of 20.°C.The surrounding air is at the same pressure,but its temperature is 25°C.When the system has equilibrated with its surroundings,both systems and surroundings are at 25°C and 1 atm.In changing from the initial to the final state,which one of the following relationships regarding the system is correct?

Accepted Answer

The answer of An ideal gas (the system)is contained in...

Question 14

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings.If the initial internal energy,E,is 61.2 kJ,what is the final value of E?

Accepted Answer

The change in internal energy of the system can be calculated using the first law of thermodynamics:
∆E = Q - W
∆E = 21.6 kJ - 6.9 kJ
∆E = 14.7 kJ
The final value of internal energy can be found by adding this change to the initial internal energy:
E_final = E_initial + ∆E
E_final = 61.2 kJ + 14.7 kJ
E_final = 75.9 kJ
Therefore, the final value of E is 75.9 kJ, which corresponds to choice C.

Question 15

Which one of the following relationships is always correct?

Accepted Answer

The relationship H = E + PV is always correct, where H is enthalpy (the sum of internal energy and pressure-volume work), E is internal energy, P is pressure, and V is volume. This is a fundamental thermodynamic relationship. The other options are either only applicable in certain situations (A- conservation of mechanical energy, B- first law of thermodynamics, E- specific to constant volume processes) or are complex equations that may not always hold true (C- a molecular mechanics equation).

Question 16

A system delivers 225 J of heat to the surroundings while delivering 645 J of work.Calculate the change in the internal energy,$\Delta$E,of the system.

Accepted Answer

The answer of A system delivers 225 J of heat...

Question 17

A system which undergoes an adiabatic change and does work on the surroundings has

Accepted Answer

The answer of A system which undergoes an adiabatic change...

Question 18

A Snickers® candy bar contains 280 Calories,of which the fat content accounts for 120 Calories.What is the energy of the fat content,in kJ?

Accepted Answer

To convert calories to kilojoules, we need to multiply by 4.184.
So, the total energy in the Snickers bar is 280 x 4.184 = 1171.52 kJ.
The energy from fat is 120 x 4.184 = 502.08 kJ.
Therefore, the energy of the fat content is 5.0 x 10^2 kJ, which is choice C.

Question 19

A system delivers 1275 J of heat while the surroundings perform 855 J of work on it.Calculate $\Delta$E in J.

Accepted Answer

The answer of A system delivers 1275 J of heat...

Question 20

A system that does no work but which transfers heat to the surroundings has

Accepted Answer

A system that does no work but transfers heat to the surroundings is an example of an exothermic process. Heat flows out of the system, so q (heat) is negative. Since no work is done, W (work) is zero. Therefore, based on the First Law of Thermodynamics: ΔU = q + W, the change in internal energy of the system (ΔU) is equal to the negative of q. Since q is negative, ΔU is positive: the internal energy of the system increases.

The internal energy of a system increases when the temperature of the system increases, so the system must gain heat from the surroundings. Since q is negative (heat flows out of the system), F1F1S1F1F1F10E must also be negative to compensate so that the change in internal energy is positive. Therefore, the correct choice is B: q < 0, F1F1F1S1F1F1F10E < 0.

Quiz 6: Thermochemistry: Energy Flow and Chemical Change

Cold packs,whose temperatures are lowered when ammonium nitrate dissolves in water,are carried by athletic trainers when transporting ice is not possible.Which of the following is true of this reaction?

A system that does no work but which receives heat from the surroundings has

A system initially has an internal energy E of 501 J.It undergoes a process during which it releases 111 J of heat energy to the surroundings,and does work of 222 J.What is the final energy of the system,in J?

Natural gas,or methane,is an important fuel.Combustion of one mole of methane releases 802.3 kilojoules of energy.How much energy does that represent in kilocalories?

A system contracts from an initial volume of 15.0 L to a final volume of 10.0 L under a constant external pressure of 0.800 atm.The value of w,in J,is

A system receives 575 J of heat and delivers 425 J of work.Calculate the change in the internal energy, $\Delta$ E,of the system.

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. The work (w) done by the system,in J,is

A system which undergoes an adiabatic change and has work done on it by the surroundings has

The dissolution of barium hydroxide in water is an exothermic process.Which of the following statements is correct?

Which of the following is not a state function?

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings.If the initial internal energy,E,is 61.2 kJ,what is the final value of E?

Which one of the following relationships is always correct?

A system delivers 225 J of heat to the surroundings while delivering 645 J of work.Calculate the change in the internal energy, $\Delta$ E,of the system.

A system which undergoes an adiabatic change and does work on the surroundings has

A Snickers® candy bar contains 280 Calories,of which the fat content accounts for 120 Calories.What is the energy of the fat content,in kJ?

A system delivers 1275 J of heat while the surroundings perform 855 J of work on it.Calculate $\Delta$ E in J.

A system that does no work but which transfers heat to the surroundings has

Quiz 6: Thermochemistry: Energy Flow and Chemical Change

Cold packs,whose temperatures are lowered when ammonium nitrate dissolves in water,are carried by athletic trainers when transporting ice is not possible.Which of the following is true of this reaction?

A system that does no work but which receives heat from the surroundings has

A system initially has an internal energy E of 501 J.It undergoes a process during which it releases 111 J of heat energy to the surroundings,and does work of 222 J.What is the final energy of the system,in J?

Natural gas,or methane,is an important fuel.Combustion of one mole of methane releases 802.3 kilojoules of energy.How much energy does that represent in kilocalories?

A system contracts from an initial volume of 15.0 L to a final volume of 10.0 L under a constant external pressure of 0.800 atm.The value of w,in J,is

A system receives 575 J of heat and delivers 425 J of work.Calculate the change in the internal energy, Δ\DeltaΔ E,of the system.

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. The work (w) done by the system,in J,is

A system which undergoes an adiabatic change and has work done on it by the surroundings has

The dissolution of barium hydroxide in water is an exothermic process.Which of the following statements is correct?

Which of the following is not a state function?

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings.If the initial internal energy,E,is 61.2 kJ,what is the final value of E?

Which one of the following relationships is always correct?

A system delivers 225 J of heat to the surroundings while delivering 645 J of work.Calculate the change in the internal energy, Δ\DeltaΔ E,of the system.

A system which undergoes an adiabatic change and does work on the surroundings has

A Snickers® candy bar contains 280 Calories,of which the fat content accounts for 120 Calories.What is the energy of the fat content,in kJ?

A system delivers 1275 J of heat while the surroundings perform 855 J of work on it.Calculate Δ\DeltaΔ E in J.

A system that does no work but which transfers heat to the surroundings has

A system receives 575 J of heat and delivers 425 J of work.Calculate the change in the internal energy, $\Delta$ E,of the system.

A system delivers 225 J of heat to the surroundings while delivering 645 J of work.Calculate the change in the internal energy, $\Delta$ E,of the system.

A system delivers 1275 J of heat while the surroundings perform 855 J of work on it.Calculate $\Delta$ E in J.