Answer:
 
D) It has a different unit than atomic mass.
 
        
             
        
        
        
Answer:
C + 2H2 ⇒ CH4
Explanation:
In order to balance a chemical equation you need to make sure that the number of atoms on both sides are equal
C + H2 = CH4
C = 1
H = 2
Products:
C = 1
H = 4
H2 = 2 × 2 = 4
C + 2H2 ⇒ CH4
Hope this helps.
 
        
             
        
        
        
Answer:
What mass (g) of barium iodide is contained in 188 mL of a barium iodide solution that has an iodide ion concentration of 0.532 M?
A) 19.6
B) 39.1
C) 19,600
D) 39,100
E) 276
The correct answer to the question is 
B) 39.1  grams
Explanation:
To solve the question
The molarity ratio is given by 
188 ml of 0.532 M solution of iodide. 
Therefore we have number of moles = 0.188 × 0.532 M = 0.100016 Moles
To find the mass, we note that the Number of moles =  from which we have
 from which we have
Mass = Number of moles × molar mass
Where the molar mass of Barium Iodide = 391.136 g/mol
 = 0.100016 moles ×391.136 g/mol = 39.12 g
 
        
             
        
        
        
According to provided equation it is clear that Zn metal is oxidized from Zn⁰ into Zn²⁺ which means that Zn metal dissolves and forming Zn²⁺ solution so the correct answer is:
mass of the Zn(s) electrode decreases