What is the H+ if the pH of a solution is 1.65?
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Answer:
The percentage (by mass) of KBr in the original mixture was 33.1%.
Explanation:
The mixture of KCl and KBr has a mass of 3.595g, thus the sum of the moles of KCl (<em>x</em>) multiplied by it molar mass (74.5g/mol) and the moles of KBr (<em>y</em>) multiplied by it molar mass (119g/mol) is the total mass of the mixture:
Also, after the conversion of KBr into KCl, the total mass of 3.129 g is only from KCl moles, hence
But the 0.042 moles came from the originals KCl and KBr moles, thus
Now it is possible to propose a system of equations:
Solving the system of equations,
0.010 moles of KBr multiplied it molar mass is
Therefore, the percentage (by mass) of KBr in the original mixture was:
%
Explanation:
It is known that each metal has a different work function and it is just the energy required to remove the electron from the surface.
The relation between energy and work function is as follows.
where, = energy of photon
Q = work function
K.E = kinetic energy of electron
When the value of Q is large then the amount of energy required by the photon is also large and vice-versa.
And, when there is not sufficient energy to remove an electron from metal surface or energy is less than its work function then electron will not be removed.
On the other hand, when incoming photon will have enough energy then electron will be ejected.
In the given situation, light from laser A is not able to remove the electron from metal surface which means that energy of photon is less than work function Q.
As, both B and C are able to remove electron from the surface of metal. So, after the removal of electrons rest of the energy of photons is transferred to eject electrons and this energy is converted into kinetic energy.
As energy of B is greater than the energy of C and A has the lowest energy among all.
Therefore, order of energy from lowest to highest is as follows.
A < C < B
Now, the relation between energy and wavelength is as follows.
E =
where, = wavelength
So, energy is inversely proportional to wavelength. Therefore, increase in energy means decrease in wavelength.
Therefore, increasing order of wavelength is as follows.
B < C < A