Answer:
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Answer:
3
Explanation:
Applying,
 = R/R'............... Equation 1
 = R/R'............... Equation 1
Where n' = number of halflives that have passed, R = Original atom of the substance, R' = atom of the substance left after decay.
From the question,
Given: R = 40 atoms, R' = 5 atoms
Substitute these values into equation 1
 = 40/5
 = 40/5
 = 8
 = 8
 = 2³
 = 2³
Equation the base,
n' = 3
 
        
             
        
        
        
Each year over 100,000 new organic compounds are produce
        
                    
             
        
        
        
As the atomic mass of iron is 55.847u
We say that it is the mass of one mole of iron.
By formula it can be find by
No.of mole=mass in g/molar mass
Mass in gram = no.of mole x molar mass
No.of mole =1 
Molar mass = 55.847g
Mass in gram = 1x55.847
= 55.847g of Fe