Answer:
i think it's a (not sure) 
 
        
             
        
        
        
Answer:
The answer to your question is 0.269 g of Pb
Explanation:
Data
Lead solution = 0.000013 M 
Volume = 100 L
mass = 0.269 g
atomic mass Pb = 207.2 g
Chemical reaction
                         2Pb(s) + O₂(aq) + 4H⁺(aq) → 2H₂O(l) + 2Pb₂⁺(aq)
Process
1.- Calculate the mass of Pb in solution
Formula
Molarity = 
Solve for number of moles
Number of moles = Volume x Molarity
Substitution
Number of moles = 100 x 0.000013 
Number of moles = 0.0013 
2.- Calculate the mass of Pb formed.
                        207.2 g of Pb ----------------- 1 mol
                              x g             ----------------- 0.0013 moles
                         x = (0.0013 x 207.2) / 1
                         x = 0.269 g of Pb                                                                 
 
        
                    
             
        
        
        
Answer:
a thermos bottle uses a vacuum to keep heat in the thermos. 
 
        
             
        
        
        
Answer:
Freezing and condensation
Explanation:
Because they are exothermic, they release energy
 
        
             
        
        
        
In Fisher esterification, sulfuric acid is used as a catalyst and its function is to convert the carboxylic compound in its conjugate acid. This favours the nucleophilic attack of the alcohol. To act as a catalyst you need a strong acid, therefore sulphuric acid is suitable for this kind of reaction.