The chemical reaction involving sodium and oxygen as given in the reaction: 4Na + O2 → 2Na2O is a synthesis reaction.
<h3>What are chemical reactions?</h3>
Chemical reactions are changes which occur in the chemical composition of atoms of substances which results in the formation of new substances.
There are different types of chemical reactions such as:
- synthesis reaction
- displacement reaction
- double displacement reactions
A synthesis reaction is a reaction in which two or more substances combine to form a new product.
Therefore, the chemical reaction involving sodium and oxygen as given in the reaction: 4Na + O2 → 2Na2O is a synthesis reaction.
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D.) a transformation of light energy into chemical energy
Answer:
b and d hope this helped
Explanation:
turtles don't have gills and neither does owls so anything
without gills
It is important in gravimetric analysis to add an excess amount of precipitating ions to a solution containing an analyte because it helps to determine the mass of the analyte.
<h3>What is Gravimetric analysis?</h3>
This is a method which is used in the determination of the quantitative determination of the ion being analyzed(analyte) based on its mass.
Adding an excess amount of precipitating ions to a solution containing an analyte will make it easier for the mass of an analyte to be determined.
It is also important for the precipitate to be a pure substance with a definite and known composition which therefore makes it the most appropriate reason.
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Answer: 
moles
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass , occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
Given mass of ethanol = 0.2301
Molar mass of ethanol = 46.07 g/mol
Thus there are moles of ethanol are present in the sample.
