Answer:
first number is the correct answer
 
        
                    
             
        
        
        
Answer:
chemical energy into thermal energy
Explanation:
The reaction taking place is as follows 
2C₂H₂ + 5O₂ = 4CO₂ + 2H₂O + Heat 
In this reaction bonds present in acetylene is broken and new bond present in water and carbon dioxide are formed . In the whole process of bond breaking and bond formation , there is net loss of energy and that energy is released as heat energy . 
Thus we can say that in the whole process , chemical energy is converted into heat energy . 
 
        
             
        
        
        
He may use a pipette with a volume greater than 25 ml to transfer the solution.
        
             
        
        
        
For every 1 molecule of Magnesium hydroxide or Mg(OH)2 there will be 2 molecules of HCl neutralized. 
If molar mass of magnesium hydroxide is 58.3197g/mol, the amount of mol in 5.50 g magnesium hydroxide should be: 5.50g/ (<span>58.3197g/mol)= 0.0943mol.
Then, the amount of HCl molecule neutralized would be: 2* </span>0.0943mol= 0.18861 mol
If molar mass of HCl is 36.46094 g/mol, the mass of the molecule would be: 0.18861 mol* 36.46094g/mol = 6.88grams