The balanced equation of the combustion of the propane is

From the above chemical equation, it is clear that 1 mole of propane requires 5 moles of oxygen to undergo complete combustion as the result of this reaction, 3 moles of carbon-di-oxide and 4 moles of water molecules will be produced.
Therefore one-half mole of propane requires 2.5 moles of oxygen to undergo complete combustion. And in the reaction, 1.5 moles of carbon-di-oxide and 2 moles of water molecules are produced.
Therefore the answer is, 'One-half of propane combines with 2.5 moles of oxygen to produce 2 moles of water and 1.5 moles of carbon dioxide'
Answer:
The question does not state how the answer is to be entered. I would use 10% because that is most common.
Explanation:
You are using 300 J of energy to get 30 J of light energy. The fact that you can account for the left over energy is not relevant.
Efficiency = Work Out / Work In
Efficiency = 30 J / 300 J = 0.1
If you need this as a %, you can multiply by 100
Efficiency = 0.1 * 100 = 10%
Answer:
c) 2Q
Explanation:
From the given information:
The pressure inside a pipe can be expressed by using the formula:

Since the diameter in both pipes is the same, we can say:

where;
length of the first pipe A
and the length of the second pipe B 
Since the difference in pressure is equivalent in both pipes:
Then:




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