Answer:
combustion is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.
 
        
             
        
        
        
FeBr₃ ⇒ limiting reactant
mol NaBr = 1.428
<h3>Further explanation</h3>
Reaction
2FeBr₃ + 3Na₂S → Fe₂S₃ + 6NaBr
Limiting reactant⇒ smaller ratio (mol divide by coefficient reaction)
211 g of Iron (III) bromide(MW=295,56 g/mol), so mol FeBr₃ :

186 g of Sodium sulfide(MW=78,0452 g/mol), so mol Na₂S :

Coefficient ratio from the equation FeBr₃ :  Na₂S = 2 : 3, so mol ratio :

So  FeBr₃ as a limiting reactant(smaller ratio)
mol NaBr based on limiting reactant (FeBr₃) :

 
        
             
        
        
        
Question:
How could you use a model to show the cause-and-effect relationship between Earth's rotation and the apparent motion of the stars across the night sky?
Answer:
Gravity? or density because of the pull from the sun.
 
        
                    
             
        
        
        
Answer:
May you post a picture for us to understand?
 
        
             
        
        
        
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Answer:
Your answer would be a). 2.0 × 10-9
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Work:
In your question the "ph" of a 0.55 m aqueous solution of hypobromous acid temperature is at 25 degrees C, and it's "ph" is 4.48.
You would use the ph (4.48) to find the ka for "hbro"
[H+] 
= 
10^-4.48
 = 
3.31 x 10^-5 M
 =
 [BrO-] 
or: [H+] = 10^-4.48 = 3.31 x 10^-5 M = [BrO-] 
Then you would find ka:
(3.31 x 10^-5)^2/0.55 =2 x 10^-9
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<em>-Julie</em>