Properties of Matter Flashcard

Front

A piston containing an ideal gas expands isothermally from 7 atm pressure to 2 atm pressure. The energy of the system (that is, the contents of the piston) remains constant during this process.

Back

True

Front

Under what condition is the enthalpy change for a process equal to the heat transferred to the system? Options: constant volume, constant pressure, constant temperature, reversible expansion, expansion at a constant pressure followed by reversible compression

Back

constant pressure

Front

Energy is a good indicator of the direction of spontaneous change for macroscopic mechanical objects but not for molecular processes.

Back

True

Front

Which of the following statements about potential energy is true?

• The potential energy of an ideal gas is equal to its kinetic energy.
• The potential energy of an atom is the work done in moving the atom from infinity to its present position.
• Potential energy is always absolutely conserved.
• The potential energy of a system always increases.
• Potential energy is an intensive function.

Back

The potential energy of an atom is the work done in moving the atom from infinity to its present position.

Front

A reaction that releases energy is called an ________ reaction.

Back

exothermic

Front

Electrostatic interactions are governed by ________'s law.

Back

Coulomb

Front

The energy for van der Waals interactions approaches _____ as the distance between atoms goes to zero and approaches _____ at infinite distance.

Back

infinity, zero

Front

One mole of an ideal monatomic gas is initially at 300 K and 1010 J•L⁻¹ pressure inside a cylinder with a frictionless piston. The cylinder is an isolated (adiabatic) system. The gas expands against zero external pressure. When the volume expands to 24.7 L, a peg stops the piston. Calculate ΔU (the change in energy), q (the heat transferred to the system), and w (the work done by the system) when the expansion is isothermal and reversible.

Back

ΔU = 0, q = 0, w = 0

Front

Calculate ΔU, q, and w for one mole of an ideal monatomic gas initially at 300 K and 1010 J•L⁻¹ pressure during isothermal expansion against 101 J•L⁻¹.

Back

ΔU = 0, q = 2244 J, w = -2244 J

Front

The complete oxidation of one mole of a sugar produces carbon dioxide and water. 2000 kJ of heat is transferred from the system to the surroundings. The rearrangement of bonds as 0.5 moles of the sugar are oxidized generates heat in an open test tube (101 J•L⁻¹ pressure and 300 K temperature). What is the change in internal energy of the system (ΔU)? What is the change in enthalpy of the system (ΔH)?

Back

ΔU = -1000 kJ, ΔH = -1000 kJ