Aleksei’s family purchased a new water heater that is a heat pump. after installation, aleksei noticed that the room containing the new water heater felt cooler than the rest of the house. what is the best explanation for why the room with the heat pump was cooler than the rest of the house? a) thermal energy from the water was transferred to the surrounding air. b) the burning fuel increased the thermal energy in the air. c) thermal energy from the air surrounding the water heater was transferred to the water. d) the burning fuel absorbed thermal energy from the surrounding air.

Curious carl calculated the density of a cube to be 4.50 g/cm3. what is the density of the cube in g/l?

The particle in a two-dimensional well is a useful model for the motion of electrons around the indole ring (3), the conjugated cycle found in the side chain of tryptophan. we may regard indole as a rectangle with sides of length 280 pm and 450 pm, with 10 electrons in the conjugated p system. as in case study 9.1, we assume that in the ground state of the molecule each quantized level is occupied by two electrons. (a) calculate the energy of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels. 9.27 electrons around the porphine ring (4), the conjugated macrocycle that forms the structural basis of the heme group and the chlorophylls. we may treat the group as a circular ring of radius 440 pm, with 20 electrons in the conjugated system moving along the perimeter of the ring. as in exercise 9.26, assume that in the ground state of the molecule quantized each level is occupied by two electrons. (a) calculate the energy and angular momentum of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels.

Abicycle slows down when the rider applies the brakes. what type of energy transformation is involved in this example? a. kinetic energy into heat energy b. heat energy into potential energy c. potential energy into kinetic energy d. kinetic energy into mechanical energy