<span>12.4 g
First, calculate the molar masses by looking up the atomic weights of all involved elements.
Atomic weight manganese = 54.938044
Atomic weight oxygen = 15.999
Atomic weight aluminium = 26.981539
Molar mass MnO2 = 54.938044 + 2 * 15.999 = 86.936044 g/mol
Now determine the number of moles of MnO2 we have
30.0 g / 86.936044 g/mol = 0.345081265 mol
Looking at the balanced equation
3MnO2+4Al→3Mn+2Al2O3
it's obvious that for every 3 moles of MnO2, it takes 4 moles of Al. So
0.345081265 mol / 3 * 4 = 0.460108353 mol
So we need 0.460108353 moles of Al to perform the reaction. Now multiply by the atomic weight of aluminum.
0.460108353 mol * 26.981539 g/mol = 12.41443146 g
Finally, round to 3 significant figures, giving 12.4 g</span>
        
             
        
        
        
Reduction is the process by which eletrons are gained by an atom. 
        
             
        
        
        
Answer:
(a) 
   (b) 
Explanation:
The reaction that is carried out by the enzyme catalase produces 
 
 The reaction that is carried out by the enzyme catalase produces 
 
        
             
        
        
        
Answer:
1.  negative
2.  positive
3.  neutral
Explanation:
Ok so it looks like they are asking for the charge (positive, negative, or neutral) of each thing
So for 1, it would be negative, because it's pointing to an electron.  Electrons always have a negative charge. 
So for 2, it would be positive, because it's pointing to a proton.  Protons always have a positive charge
So for 3, it would be neutral, because it's pointing to a neutron.  Neutrons always have a neutral charge.
 
        
             
        
        
        
Answer:
Strontium is a soluble earth metal with the nuclear number 38. Phosphate is a polyatomic particle containing phosphorus and oxygen molecules. Strontium loses electrons to turn out to be emphatically charged, and phosphate is an adversely charged particle.
Explanation: