Answer: compound
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper 
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water 
Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present. Example: Air
Frequency is defined as the number of waves per second. In this machine 25 waves pass in one second.
We need to calculate the number of waves that pass a particular point during one second.
During 2 seconds -25 waves
Therefore in one second - 25/2 = 12.5 waves/s.
1 wave per second has the unit Hertz (Hz)
Therefore answer is 12.5 Hz
the correct IUPAC name of the compound is 1-Butanal.
<h3>What are IUPAC names?</h3>
It is a system of naming organic compounds based on the longest carbon-to-carbon single bonds. It does not matter whether these longest chains are continuous or in a ring.
Thus, when the compound with the chemical formula, CH3-CH2-CH2CHO is considered. The longest carbon-to-carbon chain is 4. The 1st carbon carries a functional group known as an aldehyde.
Aldehydes are equipped with the carbonyl group and have the general formula R−CH=O. They are also sometimes referred to as formyl.
Aldehydes are named after their parent alkane chains with a slight modification. The 'e' is replaced with 'al'
The aldehyde in this case has four carbons. This means that the parent alkane is Butane. Therefore, the name of the compound will be 1-Butanal.
More on IUPAC names can be found here: brainly.com/question/16631447
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Answer:
B. as a food preservative in the manufacture of detergents
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