For each of the following, define a system and its surrounding and give the direction of heat transfer.?

Question

a. propane is burning a burner in the laboratory
b. after you have a swim, water droplets on your skin evaporated
c. water, originally at 25 degree celsius, is placed in the freezing compartment of a refrigerator.
d. two chemicals are mixed in a flask on a laboratory bench. a reaction occurs and heat is evolved.

Answer 1

a) propane gives energy

b) your body gives energy to the water and you feel cold

C) water looses energy

7) it is an exothermic reaction

Answer 2

A) this is an example of natural convection. Buoyancy and gravitational field drive differential temperatures of a fluid body to produce a bulk flow. If the flow isn't due to buoyancy, gravitational fields, and differential temperatures of a fluid body, then the mode of heat transfer is called forced convection. B) Radiation. Infrared is used to heat the food via electromagnetic waves. The lights emit it and the food absorbs it. C) Conduction. Direct contact heat transfer due to elastic collisions of interacting atoms.