Acryogenics laboratory uses liquid nitrogen to store biological samples. the liquid nitrogen is transferred to the storage freezer through a small cylindrical tube. the liquid nitrogen has a constant temperature of -196 °c, and the copper tube has a 1.5 cm outside diameter and a thickness of 0.21 cm. it is coated with a layer of insulating soft vulcanized rubber that is 0.57 cm thick. the convective heat transfer coefficient for the liquid nitrogen is 144 w/m²k, and air on the outside of the insulation has a bulk temperature of 27 °c and a convective heat transfer coefficient of 62 w/m -k. a. what is the heat flux across the tube at the inside surface of the copper tube? what is the heat flux across the tube at the outside surface of the rubber? (be sure to include a direction with your answers) b. what is the temperature on the outside of the copper tube, next t you may look up the thermal conductivities of copper at 200k and rubber at 300k. you may also assume that the temperature of the liquid nitrogen does not change appreciably from the entrance to the exit.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

pla·gia·rism

/ˈplājəˌrizəm/

learn to pronounce

noun

the practice of taking someone else's work or ideas and passing them off as one's own.

explanation:

a:

by the combination of an unlimited number of elements

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.