Answer : The mass of oxygen formed must be 3.8 grams.
Explanation :
Law of conservation of mass : It states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
This also means that total mass on the reactant side must be equal to the total mass on the product side.
The balanced chemical reaction will be,

According to the law of conservation of mass,
Total mass of reactant side = Total mass of product side
Total mass of
= Total mass of 
As we are given :
The mass of
= 25.3 grams
The mass of
= 23.4 grams
So,



Therefore, the mass of oxygen formed must be 3.8 grams.
A locating agent is needed in an experiment to separate amino acids by chromatography as it helps to analyze colorless substances on paper.
<h3>What is chromatography?</h3>
Chromatography is an analytical method frequently used to separate a chemical mixture into its components, allowing for in-depth analysis of each component.
There are many different types of chromatography including liquid, gas, ion-exchange, and affinity chromatography, but they all use the same basic principle.
<h3>What is the use of a locating agent in Chromatography?</h3>
In paper chromatography, colorless compounds are examined using a locating agent.
It is a chemical that combines with colorless substances to produce colorful compounds that are easy to see for analysis. Ninhydrin spray is an example of a locating agent of this type.
Thus, a locating agent is used in an experiment to separate amino acids by chromatography as it helps in determining colorless substances on paper.
Learn more about chromatography:
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Answer:
1) Oil is less dense than water so when oil spills, it spreads across the entire water surface.
2) The oil spreads very quickly with lighter oils such as gasoline.
3) Wind, Currents, and Warm Temperatures will cause Oil to spread quicker.
An atom hopefully this helps