WorksheetsAP Chem #3 - Ch 5 -6
Total questions: 22
Worksheet time: 37mins
Thermochemistry is small portion of thermodynamics, which is studying how energy changes during a chemical reaction. Some reactions will absorb heat, while others will release it, and can do work.
Complete this fundamental principle of thermochem:
Energy is _____ when chemical bonds are formed; energy is _____ when chemical bonds are broken.
consumed / released
released / consumed
Energy can be converted from one form to another, but it is neither created nor destroyed.
1st Law of Thermodynamics
2nd Law of Thermodynamics
3rd Law of Thermodynamics
0th Law of Thermodynamics
When analyzing energy changes, we need to focus on a limited and well-defined part of the universe to keep track of the energy changes that occur. The portion we single out for study is called the _____; everything else is called the _____.
system / surrounding
study / system
surrounding / system
surrounding / study
The internal energy, E, of a system is the sum of all the kinetic and potential energy s of the components of the system. While we cannot directly measure the final or initial energy of a system, we can measure the change in energy or Δ E. Infer the meaning of a negative Δ E.
Efinal > Eintital; energy is absorbed
Efinal < Eintital; energy is released
There is a small change in energy
There is a large change in energy
What is an example of an isolated system? An isolated system is one in which there is not heat exchanged.
Coffee in an insulated thermos.
Hot chocolate, sitting all alone in a coffee mug.
A cold football fan, wrapped in a blanket.
A cold Dr Pepper in the refrigerator.
The energy change in a system, ΔE, does not have to be heat (q) alone, but could be absorbed or released as work (w). What is a useful equation to calculate the work done in a system?
ΔE = q + w
w - ΔE = q
w = ΔE - q
w = ΔE / q
Gases A and B are confined in a cylinder and piston and react to form a solid product C. As the reaction occurs, the system loses 1150 J of heat to the surroundings. The piston moves downward as the gases react allowing the surroundings to do 480 J of work on the system. What is the change in the internal energy of the system?
-670 J
670 J
1630 J
-1630 J
A process in which a system loses heat is called _____.
Exothermic
Endothermic
Polythermic
Homothermic
There are two beakers, each with 50 g of 25°C water. Beaker 1 started out as 50 g of 100°C water which cooled to 25°C, and beaker 2 started out as 0°C ice and warmed to 25°C. Both beakers have the same internal energy.
True
False
Under conditions of constant atmospheric pressure, the thermodynamic quantity called _____ is used to describe the state function relating internal energy, E, pressure, P, and volume, V.
Enthalpy
Entropy
Energy
Empty
If a reaction is carried out in a series of steps, the change in enthalpy, ΔH, for the overall reaction equals the sum of the enthalpy changes for the individual steps.
Hess's Law
Boyle's Law
Charle's Law
Avogadro's Law
Two electromagnetic waves are represented above. Which wave has the higher frequency?
Wave 1
Wave 2
They are the same
Using the relationship between wavelength and frequency, calculate the frequency of red light which as a wavelength of about 6.50x10-9m.
4.61 x 1016 s-1
1.95 1/s
2.17 x 10-17 Hz
A ______________ is the minimum amount of energy that can be gained or lost by an atom.
wavelength
frequency
quantum
electron
The energy of a photon (Ephoton) must be greater than the energy change of the system.
True
False
1s2 2s2 2p6 3s2
The particle model treats light as being comprised of:
photons
electrons
neutrons
electricity
