Explanation:
its hard to explain unless we know what the question fully asks..
Polar molecules exhibit an unequal balance of charges between the individual elements of the compound. This is brought about by the large difference in their electronegativities. The H atom has the least amount of electronegativity. Then, it is a known periodic trend, that as you go downwards in a group, electronegativity decreases, and increase as you go from left to right. Thus, you can deduce that the most electronegative elements are found in the upper right corner which includes O, N and F atoms. Any bond created between Hydrogen and any of O, N and F atoms is a polar bond.
The limiting reagent will be Al
<h3>What are limiting reagents?</h3>
They are reagents that limit the quantity of products that are formed in reactions.
From the equation of the reaction:

The mole ratio of Al to O2 is 4:3.
With 2 moles of Al and 2 moles of O2, Al becomes limiting while O2 is in excess.
With 2 moles of O2, the amount of Al required should be:
2 x 4/3 = 2.67 moles.
With 2 moles of Al, the amount of O2 required should be:
2 x 3/4 = 1.5 moles
Thus, O2 is in excess by 0.5 moles.
More on limiting reagents can be found here: brainly.com/question/11848702
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Dalton's atomic theory was based on the law of conservation of mass which states that the matter can neither be created nor be destroyed but it can only transformed into one form or another. In a chemical reaction, total mass of the reactants will be equal to the total mass of the products.
Taking an example,


Mass of
= 16g
Mass of
= 
Total mass on reactant side = 
Total mass on reactant side = 80g
Mass of
= 44g
Mass of
Total mass on product side = 
Total mass on product side = 80g
It is seen from the above example that the
total mass on reactant side = total mass on product side.