Answer:
Concentration, because the amounts of reactants and products remain constant after equilibrium is reached.
Explanation:
The rate of reaction refers to the amount of reactants converted or products formed per unit time.
As the reaction progresses, reactions are converted into products. This continues until equilibrium is attained in a closed system.
When equilibrium is attained, the rate of forward reaction is equal to the rate of reverse reaction, hence the concentration of reactants and products in the system remain fairly constant over time.
When deducing the rate of reaction, concentration of the specie of interest is plotted on the y-axis against time on the x-axis. 
 
        
             
        
        
        
The correct question is as follows: 0.500 moles of potassium oxide is dissolved in enough water to make 2.00 L of solution. Calculate the molarity of this solution (plz help!)
Answer: The molarity of this solution is 0.25 M.
Explanation:
Molarity is the number of moles of a substance divided by volume in liter.
As it is given that there are 0.5 moles of potassium oxide in 2.00 L of water so, the molarity of this solution is calculated as follows.

Thus, we can conclude that molarity of this solution is 0.25 M.
 
        
             
        
        
        
francium , in the Periodic table the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. making helium is the smallest element, and francium the largest.
        
             
        
        
        
The delta H of -484 kJ is the heat given off when 2 moles of H2 react with 1 mole of O2 to make 2 moles of H2O. You don't have anywhere near that much reactants, only 1/4 as much
<span>actual delta H = 0.34  moles H2 x (-484 kJ / 2 moles H2) = 823 kJ </span>
<span>delta E = delta H - PdeltaV = 823 kJ - 0.41 kJ = 822 kJ</span>