Midterm 2 preparation

Which of the following will always increase the internal energy of a system?

• The system gains energy and performs work.

• The system gains energy and work is performed on it.

• The system loses energy and performs work.

• The system loses energy and work is performed on it.

• None of the changes A–D will always increase the internal energy of a system.

Tags

NGSS.HS-PS3-1

The dissolution of cesium hydroxide in water is exothermic (ΔHsoln = –71.55 kJ/mol). Calculate the change in temperature of a solution produced by dissolving 0.150 kg CsOH (150 g/mol) in 1.00 kg water. Assume the heat capacity of the solution is 4.18 J/(g·°C).

• +44.9°C

• +114°C

• +17.1°C

• +14.9°C

• +114°C

Tags

NGSS.HS-PS3-4

The standard enthalpy of combustion of liquid hexane (C6H14) is –4163 kJ/mol. What is the standard enthalpy of formation of C6H14, given that the standard enthalpies of formation of CO2(g) and H2O(l) are –394 and –286 kJ/mol, respectively?

• +203 kJ/mol

• +362 kJ/mol

• –3483 kJ/mol

• –203 kJ/mol

• –362 kJ/mol

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Which of the following bar charts shows the correct energy changes that occur in a beaker full of ice (system) as it warms up on a lab bench (surroundings)?

• [Bar chart a]

• [Bar chart b]

• [Bar chart c]

• [Bar chart d]

• none of these

Tags

NGSS.HS-PS3-2

NGSS.HS-PS3-4

Which statement below regarding heating curves is FALSE?

• A heating curve tracks the temperature of a system as it is heated at a constant rate.

• Different substances will have different heating curves.

• A heating curve will reflect the amount of material present.

• When a substance undergoes a phase change, there is no energy change because the temperature is constant.

• If a cooling curve were to be made, the amounts of energy would be equal to those in a heating curve but opposite in sign.

Tags

NGSS.HS-PS3-4

What is the change in internal energy (ΔE) of the system when it loses 76.0 J of heat while the surroundings perform 29.0 J of work?

• -76.0 J

• +105.0 J

• -105.0 J

• +47.0 J

• -47.0 J

Tags

NGSS.HS-PS3-1

The following diagrams illustrate the flow of energy (q) and work (w) in different processes. In which ones does the internal energy of the system DEFINITELY increase? Assume the magnitudes of q and w are equal.

• [Diagram a]

• [Diagram b]

• [Diagram c]

• [Diagram d]

• none of these

Tags

NGSS.HS-PS3-4

Which of the following statements about energy, systems, and surroundings is NOT true?

• The system can be a chemical reaction that occurs in a sample of matter.

• The surroundings experience the same energy change as the system in order to keep the total energy in the universe constant.

• The system is the part of the universe that is the focus of thermochemical study.

• The surroundings can provide thermal energy to the system.

• The system can do work on the surroundings.

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

NGSS.HS-PS3-4

The capacity to do work is a definition of

• heat.

• thermochemistry.

• work.

• energy.

• force.

Tags

NGSS.HS-PS3-2

Create the Born–Haber cycle and calculate the lattice energy of lithium oxide (Li2O) from the following data:

• –2586 kJ/mol

• –2972 kJ/mol

• –3081 kJ/mol

• –2205 kJ/mol

• –2831 kJ/mol

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1