Answer:
the heat given off is 75 J.
Explanation:
Given;
latent heat of fusion of lead, L= 25 J/g
mass of liquid lead, m = 3.0g
The heat given off is calculated as;
H = Lm
Where;
H is the quantity of heat given off
H = 25 x 3
H = 75 J.
Therefore, the heat given off is 75 J.
Answer:
<em>By showing that changing the frequency of light causes the emission of faster electrons.
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Explanation:
<em>The photoelectric effect happens when light strikes a metal surface causing the emission of electrons from it (photoelectrons).
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<em>If you increase the intensity of the light you get, as acresult, more electrons emitted but their kinetic energy does not increase.
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<em>If you increase the frequency of the incident light the number of photoelectrons emitted does not increase while the velocity, and so their kinetic energy, increases...the emitted electrons are more...energetic!
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<em>
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<em>This can be explained considering the incident light as a shower of particle-like packets of energy (photons); if you increase the intensity you simply increase the number of packets (all with the same energy) hitting the metal; these can be used by a lot of electrons to escape.
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<em>On the other hand if you increase the frequency the number of packets remains the same (emitting fewer electrons perhaps) but the energy carried by each of them increases.
</em>
<em>Each packet carries an energy directly proportional to the frequency.</em>
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C3H8 + 5O2 ------> 3CO2 + 4H2O
from reaction 1 mol 5 mol
given 1.82 mol x mol
x=(1.82*5)/1 = 9.10 mol CO2
