Answer:
a. 58.5 g/mol
b. 0.1 mol
Explanation:
a. 
The molar mass of Na is 23.0 g/mol. The molar mass of Cl is 35.5 g/mol. The molar mass of NaCl is:
M(Na) + M(Cl) = 23.0 g/mol + 35.5 g/mol = 58.5 g/mol
b. A healthy adult should eat no more than 6 g of salt in one day. The moles corresponding to 6 g of NaCl are:
6 g × (1 mol/58.5 g) = 0.1 mol
 
        
             
        
        
        
Answer:
5SiO2 + 2CaC2 = 5Si + 2CaO + 4CO2
Explanation:
balancing equations is a lot of trial and error. My strategy to approaching this equation was to get the O's balanced. After trying several combonations I found that I needed 10 O's on each side of the equation for the other elements to match up. After I balanced the O's, I balanced my C's to 4 on each side. Then I balanced my Ca's to have 2 on each side. And last but not least I balanced my Si to have 5 on each side.
 
        
             
        
        
        
15. D is correct, exothermic reactions release heat 
I am not sure about 16