Answer:
Q = 62 ( since we are instructed not to include the units in the answer)
Explanation:
Given that:
Q = ???
Now the gas expands at constant pressure until its volume doubles
i.e if
Using Charles Law; since pressure is constant
mass of He =number of moles of He × molecular weight of He
mass of He = 3 kg × 4
mass of He = 12 kg
mass of Ar =number of moles of Ar × molecular weight of Ar
mass of He = 7 kg × 40
mass of He = 280 kg
Now; the amount of Heat Q transferred =
From gas table
∴ Q =
Q =
Q = 62 MJ
Q = 62 ( since we are instructed not to include the units in the answer)
Answer:
The correct option is: 2. Propane
Explanation:
Minimum ignition energy, abbreviated as MIE, is the minimum energy required to ignite the flammable mixture of air at atmospheric pressure and room temperature. The unit used to measure this energy is millijoule, mJ
The values of the minimum ignition energy for the following gases are:
Butane = 0.25 mJ
Propane = 0.26 mJ
Ethylene = 0.07 mJ
Hydrogen = 0.017 mJ
Cyclohexane = 0.22 mJ
<u>Therefore,among the following gases, Propane requires the most ignition energy, 0.26 mJ. </u>
Answer a) roof equilibrium temperature is 400K
Explanation:
The roof surface is sorrounded by ambient air whose temperature is 300K and which has a convective coefficient h of 10W/m2-K.
This means that heat will be conducted to the roof from the air around at an heat Flux of 300K x 10W/m2-K = 3000w/m2
For a clear solar day with solar heat Flux of 500W/m2, total heat Flux on roof will be
Q = 500 + 3500 = 3500W/m2
Q = h(Tr-Ta)
Ts is temperature of roof,
Ta is temperature of air
3500 = 10(Tr - 50)
350 = Tr - 50
Tr = 400k
Answer b): roof equilibrium temperature will be 350K
Explanation:
At night total heat Flux is only due to hot ambient air sorrounding the surface of the roof.
Q = 3000W/m2
Q = h(Tr-Ta)
3000 = 10(Tr-50)
300 = Tr - 50
Tr = 350K