In the reaction
2H20(aq) --> O2(g) + 2H20(l)
why doesn't increasing the pressure of oxygen have any effect on the reaction rate?
Balance the equation first. What you have isn't balanced. Frankly, it doesn't look possible. You have two mols H2O on each side. Take them out and the equation reads:
??? ==> O2 which means you get oxygen from nothing. Can't do that.
It seems that the given chemical equation is not balanced correctly, as you correctly pointed out. To balance the equation properly, we need to ensure that the number of atoms of each element is the same on both sides of the equation.
Let's balance the equation:
2H2O(aq) --> O2(g) + 2H2O(l)
To balance the oxygen (O) atoms, we need two oxygen molecules (O2) on the left side:
2H2O(aq) --> O2(g) + 2H2O(l)
Now, let's balance the hydrogen (H) atoms. We have two water molecules (H2O) on each side, so the hydrogen atoms are already balanced.
The balanced equation is:
2H2O(aq) --> O2(g) + 2H2O(l)
Now, coming back to the question of why increasing the pressure of oxygen does not have any effect on the reaction rate in this particular reaction, there are a few factors to consider.
First, it's worth noting that gases, such as oxygen, can only affect the reaction rate by participating in a chemical reaction themselves. In this reaction, the oxygen gas (O2) is not consumed or produced. It acts as a spectator, meaning that it remains unchanged throughout the reaction. As a result, changing the pressure of oxygen will not affect the availability or concentration of the reactants or the rate at which the reaction proceeds.
The reaction rate is determined by factors such as the concentration of reactants, temperature, presence of catalysts, and surface area of reactants. In this case, the concentration of water (H2O) would be the significant factor affecting the reaction rate, as water is consumed to produce more water. Altering the pressure of oxygen alone will not impact the rate at which water is consumed.
To summarize, the lack of effect of increasing the pressure of oxygen on the reaction rate in this case is due to the fact that oxygen does not participate in the reaction and altering its pressure does not influence the concentration of the reacting species.