Choose the answer that describes the scientific notation for 3,134,000,000.
a. 3.143 × 10^45
b. 3.134 × 10^9
c. 31.34 × 10^9
d. 3.143 × 10^9

Air initially at 0.75 bar, 1000 k, and occupying a volume of 0.12 m^3 undergoes two processes. process 1-2: the air is compressed isothermally until the volume is halved. process 2-3: the air undergoes a constant pressure process until the volume is halved again. assume ideal gas behavior. a) determine the mass of the air, in kg. b) the work and the heat transfer for each of the two processes, in kj. (100 kj = 1 bar . m^3)

An object with initial temperature 130 ∘ f is submerged in large tank of water whose temperature is 50 ∘ f . find a formula for f ( t ) , the temperature of the object after t minutes, if the cooling constant is k = − 0.2 . remember newton's law of cooling (the rate of change of temperature with respect to time is equal to k times the difference between the temperature of the object and the surrounding temperature) ! : )

Which best term to describe a chemical reaction that absorbs energy from its surroundings? a. thermal conductor b. thermal insulator c. endothermic d. exothermic