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The mass of  chlorine gas produced by 14.5 grams of sodium chloride is 10.42 g.
The mass of  chlorine gas produced by 14.5 grams of sodium chloride is 8.81 g.
The given parameters;
- <em>mass of the sodium chloride, = 14.5 g</em>
- <em>2NaCl(s) + F2(g) → 2NaF(s) + Cl2(g)</em>
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In the reaction above, we can deduce the following;
molecular mass of 2Nacl = 2(58.44) = 116.88 g
molecular mass of 2NaF = 2(42) = 84 g
molecular mass of  Cl2 = 71 g
The mass of sodium fluoride produced by 14.5 grams of sodium chloride is calculated as follows;
 116.88 g of NaCl --------------- 84 g of NaF
 14.5 g of NaCl -------------------  ?

The mass of  chlorine gas produced by 14.5 grams of sodium chloride is calculated as follows;
 116.88 g of NaCl --------------- 71 g of Cl2
 14.5 g of NaCl ------------------- ?

Learn more here:brainly.com/question/8470145
 
        
             
        
        
        
Answer:
It could be because of rounding error somewhere in your calculations. Another thing to note is 90 +/- 4 g/mol. 
Your calculations don't have to be spot on.
 
        
             
        
        
        
Given :
Mass of gold ( Au ) is 212 gram.
To Find :
Atoms of gold present in 212 gram of gold.
Solution :
Molecular mass of gold is 197 gram.
So, number of moles of gold in 212 gram is :

Now, we know 1 mole of any element contains  atoms.
 atoms.
So, number of atoms present in 1.076 moles are :

Hence, this is the required solution.