Answer:
At the burner temp. and pressure, 18.85 litres of air is needed to completely combust each gram of propane
Explanation:
The combustion stoichiometry is as follows:
C₃H₈ + 5O₂ = 4 H₂O + 3CO₂ The molecular weights (g/mol) are:
MW 44 5x32 4x18 3x44
So each gram of propane is 1/44 = 0.02272 mol propane
and will need 5 x 0.02272 = 0.1136 mol oxygen
At 0.21 mol fraction oxygen in air, 0.1136 / 0.21 = 0.54 mol air is needed to burn the propane.
At the low pressure in the burner we can use the Ideal Gas Law
PV=nRT, or V = nRT/P
P = 1.1 x 101325 Pa = 111457 Pa
T = 195°C + 273 = 468 K
R = 8.314
and we calculated n = number of moles air = 0.54 mol
So V m³ = 0.54 x 8.314 x 468 / 111457 = 0.0188 m³ = 18.85 litres air.
Answer:
The bones of the skull and spinal column
Explanation:
The central nervous system is better protected than any other system or organ in the body. Its main line of defense is the bones of the skull and spinal column, which create a hard physical barrier to injury.
Explanation:
A student flips four different coins at the same time. Which choice shows all of the possibilities for the results of the coin toss? (H = heads, T = tails)
A HH, TT, HT, TH
B HHHT, HTTT, HHTT
C HHH, TTT, HTH, HTT
D HHHH, HTHH, HTTH, HTTT, TTTT
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YeS im Am fRom pLanet k12 And brinG anD imPortant MesSage </h2>
- The answer to your question is, <u><em>There are only so many ways matter can arrange itself within that infinite universe.</em></u>
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<em>Also if your on the same test as me heres some other sTuff that was on my test </em></h2><h2>
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Question 1 (1 point)
In Brian Greene's "A Physicist Explains Why Parallel Universes May Exist", what reason does Greene give for why he believes parallel universes may exist?
- <em>Answer: There are only so many ways matter can arrange itself within that infinite universe.</em>
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Question 2 (1 point)
Choose the best explanation for why we experience the Mandela Effect.
- <em>Answer: Our brains tend to fill in information that we cannot readily recall and make associations that are not true.</em>
Question 3 (1 point)
From the article "Time Travel Is A Fun Science Fiction Story But Could It Be Real?", Albert Einstein's Theory of Relativity is described as what?
- <em>Answer: The pulling force of gravity causes space to curve and causes time to slow down.</em>
Question 4 (1 point)
From the video " Are Wormholes The Answer To Time Travel?", how are worm holes described?
- <em>Answer: A tunnel in space connecting two regions very distant from each other. A "short cut" through space</em>
Question 5 (1 point)
Many scientists think human cloning is possible, so why haven't we made human clones yet?
- <em>Answer: Human cloning is extremely controversial and many people believe it is unethical</em>
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HOPE THIS HELPS ANYONE IF IT DOES THANK AND RATE FOR A FREE COOKIE :D
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