Molar mass Na2CO3 = 106 g/mole
Using dimensional analysis:
0.787 moles Na2CO3 x 106 g/mole Na2CO3 = g Na2CO3
Answer = 83.4 g Na2CO3
        
             
        
        
        
Each carbon atom will react with 4 hydrogen atoms to form methane (

) Since there are 2 hydrogen atoms in a hydrogen molecule (

) then each carbon atom will react with 2 hydrogen molecules. Since there are 22 hydrogen molecules half as many methane molecules will be formed, so 11. Then we can subtract 11 from 34 to find the number of carbon atoms left over.
So in summary, 11 methane molecules will be formed and there will be 23 carbon atoms left over.
 
        
                    
             
        
        
        
<u>Answer:</u> Antimony ion is the smallest and yttrium ion is the largest.
<u>Explanation:</u>
Atomic radius of an atom is defined as the total distance from the nucleus to the outermost shell of the atom.
An ion is formed when a neutral atom looses or gains electrons.
- When an atom looses electrons, it results in the formation of positive ion known as cation.
 - When an atom gains electrons, it results in the formation of negative ion known as anion.
 
As moving from left to right in a period, more and more electrons get added up in the same shell and the attraction between the last electron and nucleus increases, which results in the shrinkage of size of an atom. Hence, the size of an atom decreases.
The size of the cation is small then their neutral atom because it has less number of electrons while its nuclear charge remains the same. Thus, the nucleus attracts the electron more towards itself and leads to the decrease in size.
We are given three cations:  
Yttrium lies in Period 5, group 3 of the periodic table.
Niobium lie in Period 5, group 5 of the periodic table.
Antimony lies in Period 5, group 15 of the periodic table.
So, the order of atomic radii in increasing order follows:

Hence, antimony ion is the smallest and yttrium ion is the largest.
 
        
             
        
        
        
Answer:
Conduction 
Explanation:
Conduction is between one solid and another solid