Sharing of electrons occurs when atoms form-
a. covalent bonds
b. ionic bonds
c. ions
d. metallic bonds

Asun-sized star will spend most of its lifetime as a: white dwarf red giant protostar main-sequence star

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)

Which of the following characteristics is fixed, or definite, for all states of matter?