<span>All scientists try to base their conclusions on the experiments they have conducted and they have repeated them to be sure of it. </span>
        
                    
             
        
        
        
Answer:
0.74 grams of methane 
Explanation:
The balanced equation of the combustion reaction of methane with oxygen is:
it is clear that 1 mol of CH₄ reacts with 2 mol of O₂.
firstly, we need to calculate the number of moles of both
for CH₄:
number of moles = mass / molar mass = (3.00 g) /  (16.00 g/mol) = 0.1875 mol.
for O₂:
number of moles = mass / molar mass = (9.00 g) /  (32.00 g/mol) = 0.2812 mol. 
- it is clear that O₂ is the limiting reactant and methane will leftover.
using cross multiplication
1 mol of  CH₄ needs → 2 mol of O₂
???  mol of  CH₄  needs → 0.2812 mol of O₂
∴ the number of mol of CH₄ needed = (0.2812 * 1) / 2 = 0.1406 mol 
so 0.14 mol will react and the remaining CH₄
mol of CH₄ left over = 0.1875 -0.1406 = 0.0469 mol 
now we convert moles into grams 
mass of CH₄ left over = no. of mol of CH₄ left over *  molar mass 
                                     = 0.0469 mol * 16 g/mol = 0.7504 g 
 
So, the right choice is 0.74 grams of methane 
 
        
             
        
        
        
Explanation:
The use of microorganism in our day to day life is making medicine.
 
        
             
        
        
        
1:2:6? Ba(NO3)2 +Na2SO4 -----> BaSO4 + 2NaNO3
Ba(NO3)2
BaSO4
NaNO 3
Na2SO4