Electrons can gain the energy it needs by absorbing light. If the electron jumps from the second energy level down to the first energy level, it must give off some energy by emitting light. The atom absorbs or emits light in discrete packets called photons, and each photon has a definite energy.
Answer:
= 0.134; 
= 0.866
The partial pressure of isopropanol = 34.04 Torr; The partial pressure of propanol = 5.26 Torr
Explanation:
For each of the solutions:
mole fraction of isopropanol (
) = 1 - mole fraction of propanol (
).
Given: mole fraction of propanol = 0.247. Thus, the mole fraction of isopropanol = 1 - 0.247 = 0.753.
Furthermole, the partial pressure of isopropanol = *vapor pressure of isopropanol = 0.753*45.2 Torr = 34.04 Torr
The partial pressure of propanol = *vapor pressure of propanol = 0.247*20.9 Torr = 5.16 Torr
Similarly,
In the vapor phase,
The mole fraction of propanol () = 
Where, 
is the partial pressure of propanol and 
is the partial pressure of isopropanol.
Therefore,
= 5.26/(34.04+5.16) = 0.134
= 1 - 0.134 = 0.866
D. With the same number of protons and different number of neutrons.
Answer:
20.3-17.5=2.8ml 1ml=1cm3 vol= 2.8cm3
Explanation:
"A contactor is a electrically controlled switch which uses an electromagnetic coil to pull in the contacts.”
"A motor starter is a contactor, plus an overload relay that will drop out the coil voltage if the motor overloads. If there is not overload relay, it is not a starter any longer, it's back to being just a contactor."
