A Hilsch vortex tube operates with no moving mechanical parts and splits a gas stream into two streams: one warmer and the other cooler than the entering stream. One such tube is reported to operate with air entering at 5 bar and 20°C, and air streams leaving at 27°C and –22°C, both at 1(atm). The mass flow rate of warm air leaving is six times that of the cool air. Are these results possible? Assume air to be an ideal gas at the conditions given.

What type of reaction is represented by the following example? 2co2 (g) + 4h2o (l) + 1452 kj 2ch3oh (l) (g) + 3o2 (g) exothermic endothermic

Sarah wants to know where in her garden chamomile would grow the best. she thinks chamomile will grow best in the corner of the garden that gets the most sunlight. to test her hypothesis, she decides to plant several groups of chamomile in her garden as an experiment. which of the following variables will sarah need to measure to know which group of plants grew best? a. the location of the plants b. the type of plants c. the height of the plants d. the amount of water she gives the plants

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?