Answer: The correct answer will be 5 moles, because according to the stoichiometric ratio, 5 moles of oxygen produce 6 moles of water.
Explanation:
The balanced equation is:
⇒ 
As you can see in the balanced reaction, it is necessary 5 moles of oxygen for obtain 6 moles of water. This stoichiometric ratio can be used for calculate any amount of produced water, once you have a specific amount of oxygen.
The balanced chemical reaction for this would be written as:
2Mg + O2 = 2MgO
We use this reaction and the amount of the reactant given to calculate for the amount of magnesium oxide that is produced. We do as follows:
1.5 g Mg (1 mol / 24.31 g) ( 2 mol MgO / 2 mol Mg ) (40.30 g /1 mol ) = 2.49 g MgO produced
Answer:10.0 mL of 0.00500 M phosphoric acid
Explanation:
If we look at the Ka values of the acids, we will realize that phosphoric acid has a Ka of 7.1 * 10-3. It is the only acid in the list having acid dissociation constant less than 1. This means that it does not ionize easily in solution and a very large volume of base must be added to ensure that it reacts completely. Acids with Ka >1 are generally regarded as strong acids. All the acids listed have Ka>1 except phosphoric acid.
