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J.J. Thomson hypothesized and discovered that the atom was not the smallest unit of matter but that instead there were much smaller units. He discovered "sub-atomic particles" which make up atoms. The sub-atomic particle that Thomson discovered was the electron. He discovered this through a process of experiments testing cathode rays.
Answer : The percent yield of the reaction is, 75.6 %
Solution : Given,
Mass of Pb = 451.4 g
Molar mass of Pb = 207 g/mole
Molar mass of PbO = 223 g/mole
First we have to calculate the moles of Pb.

Now we have to calculate the moles of 
The balanced chemical reaction is,

From the reaction, we conclude that
As, 2 mole of
react to give 2 mole of 
So, 2.18 mole of
react to give 2.18 mole of 
Now we have to calculate the mass of 


Theoretical yield of
= 486.1 g
Experimental yield of
= 367.5 g
Now we have to calculate the percent yield of the reaction.


Therefore, the percent yield of the reaction is, 75.6 %
The statement is true in this situation is C. The size of Ffric is the same as the size of Fapp:
From the diagram, since the body is in equilibrium, the sum of vertical forces equals zero. Also, the sum of horizontal forces equal zero.
So, ∑Fx = 0 and ∑Fy = 0
Since Fapp acts in the negative x - direction and Ffric acts in the positive x - direction,
∑Fx = -Fapp + Ffric = 0
-Fapp + Ffric = 0
Fapp = Ffric
Also, since Fgrav acts in the negative y - direction and Fnorm acts in the positive y - direction,
∑Fy = Fnorm + (-Fgrav) = 0
Fnorm - Fgrav = 0
Fnorm = Fgrav
So, we see that the size of Fapp <u>equals</u> size of Ffric and the size of Fnorm <u>equals</u> the size of Fgrav.
So, the correct option is C
The statement which is true in this situation is C. The size of Ffric is the same as the size of Fapp.
Learn more about equilibrium of forces here:
brainly.com/question/12980489