Answer : The partial pressure of 
is, 222.93 torr
Explanation :
Half-life = 2.81 hr = 168.6 min
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the partial pressure of
The balanced chemical reaction is:
Initial pressure 760 0 0
At eqm. (760-2x) 4x x
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = time passed by the sample = 215 min
a = initial pressure of 
= 760 torr
a - x = pressure of at equilibrium = (760-2x) torr
Now put all the given values in above equation, we get:
The partial pressure of = x = 222.93 torr
Q=mc(deltaT)
Q is the amount of energy which you are looking for
M is the mass which you can find
C is the specific heat of water which is 4.18 J/gC
DeltaT is the change in temperature which you can find.
To find the mass, first you must know that the density of water is 1g/mL, meaning that 200 mL has a mass of 200 g. This means that to find the total mass (m in the equation) all you need to do is add the mass of water and NaOH.
200 g + 2.535 g=202.535 g.
To find deltaT you would need to take the final temperature minus the initial temperature.
27.8C-24.2C=3.6C
Then these values can be substituted into the equation:
q=(202.635g)(4.18J/gC)(3.6C)
Q=3049.25 J
Technically this should be rounded off to 1 significant figure (200 mL only had 1), but ignoring signficiant figure rules this should be correct. Also, sometimes other units like calories or kJ may be asked for, meaning that a conversion or alternate c value would be used.
She must have used the torch as Sun, the tennis ball as Earth and the marble as Moon.
Answer:
B. This process warms Earth's surface.
Answer: The energy of the 4-s subshell is lower than the energy of 3-d subshell.
Explanation:
During the filling of electrons in subshells, the lower energy levels are filled before the higher energy levels. Also known as Aufbau principle.
Energy of the sublevel = (n + l)
where : n = Principal quantum number
l = Azimuthal quantum number(s=0,p=1,d=2,f=3)
Energy of 4-s subshell= (4+0) = 4
Energy of 3-d subshell=(3+2) = 5
Energy of 4-s subshell is lower than the energy of 3-d subshell, that is why 4s orbital is filled before the 3-d subshell.
