Answer:
Explanation:
The net force on electron is electrostatic force between electron and proton in the nucleus . 
Fc = 
This provides the centripetal force for the circular path of electron around the nucleus . 
Centripetal force required = 
So 



 
        
             
        
        
        
CuCl2 + 2NaNO3 ---->  Cu(NO3)2 + 2NaCl
using molar masses:-
Theoretical yields:-
63.54 + 2(35.45) g  of CuCl2  produces  2(22.98 + 35.45) g of NaCl
    134.44  g .................................................... 116.86 g
       31.0 g ....................................................31.0 * 116.86 /134.44=26.95g  
 
 So percentage yield is 21.2* 100 / 26.95    =  78.7%  to nearest tenth                                                                                                              
        
                    
             
        
        
        
What do I possibly answer here? 
ask a full question pls!
        
             
        
        
        
Answer:
option C is correct = 1.14 × 10²² molecules of  CO₂ 
Explanation:
Given data:
Number of moles of CO₂ = 0.0189 mol
Number of molecules = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
For given question:
1 mole of CO₂ =  6.022 × 10²³ molecules of  CO₂ 
0.0189 mol of CO₂ ×  6.022 × 10²³ molecules of  CO₂ / 1mol
1.14 × 10²² molecules of  CO₂ 
Thus, option C is correct.
 
        
             
        
        
        
For a p type of semiconductor we need a dopant which is from 13th group in periodic table
Al , B, Ga, In Tl
So the correct element will be In : Indium
The other elements belongs to 15th group and hence will give n type semiconductor