<span>Factors that influence the reaction rates of chemical reactions include the concentration of reactants, temperature, the physical state of reactants and their dispersion, the solvent, and the presence of a catalyst.</span>
        
             
        
        
        
The elements are oxygen and carbon
        
             
        
        
        
The half-life of radium-226 is 1600 years. How many grams of a 0.25 g sample will remain after 4800 years?
this would be 0.03125 gram
        
             
        
        
        
Answer:
To speed up a reaction
Explanation:
Heat, as well as catalysts, increase the reaction rate of some chemical reactions since they cause the enzymes or reagents in charge of carrying out the transformation to products to act faster and increase their kinetic energy of reaction.
 
        
             
        
        
        
Answer:
HOFO = (0, 0, +1, -1)
Explanation:
The formal charge (FC) can be calculated using the following equation:

<u>Where:</u>
V: are the valence electrons 
N: are the nonbonding electrons
B: are the bonding electrons
The arrange of the atoms in the oxyacid is:
H - O₁ - F - O₂ 
Hence, the formal charge (FC) on each of the atoms is:
H: FC = 1 - 0 - 1/2*(2) = 0             
O₁: FC = 6 - 4 - 1/2*(4) = 0        
F: FC = 7 - 4 - 1/2*(4) = +1 
O₂: FC =  6 - 6 - 1/2*(2) = -1 
We can see that the negative charge is in the oxygen instead of the most electronegative element, which is the F. This oxyacid is atypical.  
I hope it helps you!