Answer:
The upper and lower limits for the room-temperature thermal conductivity of a magnesium oxide material having a volume fraction of 0.10 of pores that are filled with still air are
Ku = 38.252 W/mK
K lower = 0.199 W/mK
Explanation:
As we know
Ku = Vp * Kair + Vmagnesium * K metal
Ku = 0.10 *0.02 + (1-0.25) * 51
Ku = 38.252 W/mK
The lower limit
K lower = Kmetal* Kair/( Vp * Kmetal + Vmetal * K air)
K lower = (0.02*51)/(0.10*51 + 0.90 * 0.02)
K lower = 0.199 W/mK
Answer:
30 kJ
Explanation:
Arrhenius equation is given by:
Here, k is rate constant, A is Pre-exponential factor, Ea is activation energy and T is temperature.
taking natural log of both side
ln k = ln A - Ea/RT
In Arrhenius equation, A, R and T are constant.
Therefore,
is the lowering in activation energy by enzyme,
R = 8.314 J/mol.K
T = 37°C + 273.15 = 310 K
In living things, the source of the carbon-14 that is used in radiocarbon dating is carbon dioxide in the atmosphere.
Living things inhale oxygen, and exhale carbon dioxide into the atmosphere, which is why the air and atmosphere are so full of it.
