PLEASE ANSWER SOON In a science lab, Cash mixes two clear liquids together in a beaker. Bubbles are produced, and a white solid forms and settles to the bottom. Which statement below describes what happened?

a

A physical change occurred, a gas and precipitate was produced

b

A physical change occurred, only a gas was produced

c

A chemical change occurred, only a gas was produced

d

A chemical change occurred, a gas and precipitate was produced

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

What precautions should you take to prevent injuries when dealing with heavy loads?

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?