Correct answer to this question is c. water evaporating
Answer:
By heating the solution
Explanation:
Physical changes and chemical changes are the two types of changes that a substance undergoes. Physical change does not alter the substance's chemical composition, hence, can be easily reversed. There is also no new product formed. This is contrary to the occurrences of a chemical change, which cannot be reversed after a new product has been formed.
A physical change is what occurs when Adrian's teacher dissolves some sugar in a beaker of water to form a sugar solution. This change does not involve any new product formation, hence, can be reversed. The sugar can be derived back from the solution by HEATING THE SOLUTION. The water (solvent) will evaporate and the sugar (solute) will precipitate.
Kiloliters and megaliters
<u>Answer:</u> The molecules of oxygen gas that will be reduced to water are 42 molecules
<u>Explanation:</u>
We are given:
The substance having highest positive 
potential will always get reduced and will undergo reduction reaction. Here, oxygen will undergo reduction reaction will get reduced.
will undergo oxidation reaction and will get oxidized.
Substance getting oxidized always act as anode and the one getting reduced always act as cathode.
The half reactions follows:
<u>Oxidation half reaction:</u> 
( × 4)
<u>Reduction half reaction:</u> 
( × 6)
<u>Overall reaction:</u> 
We are given:
Molecules of = 28
By Stoichiometry of the reaction:
4 molecules of reacts with 6 molecules of oxygen gas
So, 28 molecules of will react with = 
molecules of oxygen gas
Hence, the molecules of oxygen gas that will be reduced to water are 42 molecules
