4)
Which is a property of a neutron?
A) 0 charge
B) +1 charge
C) -1 Charge
D) Essentially no mass

15)

Sodium has an atomic number of 11 and has a net charge of 0. When sodium combines with chlorine, it has a net charge of +1. Why?
A) Sodium loses a negative electron when forming chemical bonds.
B) Sodium gains a + proton when forming chemical bonds.
C) Sodium loses a + proton when forming chemical bonds.
D) Sodium shares a negative electron with chlorine.

17)
What can you conclude about the classification of silicon?
A) Silicon is a noble gas and has a full valence electron shell, is chemically non-reactive, colorless, odorless, and is a gas at room temperature.
B) Silicon is a metal and is shiny, malleable, ductile, conducts heat and electricity, forms basic oxides, and forms cations in aqueous solution.
C) Silicon is a nonmetal and is dull, brittle, poor conductor of heat and electricity, forms acidic oxides, and forms anions in aqueous solution.
D) Silicon is a metalloid and has properties of both metals and nonmetals - it appears lustrous, but is brittle and a poor conductor of heat and electricity.

An internally reversible refrigerator has a modified coefficient of performance accounting for realistic heat transfer processes of where qin is the refrigerator cooling rate, qout is the heat rejection rate, and is the power input. show that copm can be expressed in terms of the reservoir temperatures tc and th, the cold and hot thermal resistances rt,c and rt,h, and qin, as where rtot rt,c rt,h. also, show that the power input may be expressed as 1.39 a household refrigerator operates with cold- and hot-temperature reservoirs of tc 5 c and th 25 c, respectively. when new, the cold and hot side resistances are rc,n 0.05 k/w and rh,n 0.04 k/w, respectively. over time, dust accumulates on the refrigerator’s condenser coil, which is located behind the refrigerator, increasing the hot side resistance to rh,d 0.1 k/w. it is desired to have a refrigerator cooling rate of qin 750 w. using the results of problem 1.38, determine the modified coefficient of performance and the required power input w under (a) clean and (b) dusty coil conditions. internally reversible refrigerator qout qin w high-temperature reservoir low-temperature reservoir th th,i tc,i tc high-temperature side resistance low-temperature side resistance w qin th tc qinrtot tc qinrtot copm tc qinrtot th tc