(2) argon (4) water
The substance that cannot be broken down by chemical reaction is .
Further Explanation:
Substance is the pure form of matter while combination of atoms or molecules is termed as a mixture.
Types of substances:
1. Element
The simplest form of substance that cannot be further broken down by any chemical method is known as an element. Carbon, sulfur, and cobalt are some of the examples of elements.
2. Compound
When two or more different elements are held together by chemical bonds, compounds are formed. These can further be broken down into their respective constituents. Their properties are quite different from those of their constituent elements. NaCl, and are examples of compounds.
(1) Ammonia consists of one nitrogen and three hydrogen atoms so it is a compound. Therefore it can be broken down by chemical reactions.
(2) Argon is an element so it is the simplest form in which it can exist. Therefore it cannot be broken down by chemical reactions.
(3) Methane consists of one carbon and four hydrogen atoms so it a compound. Therefore it can be broken down by chemical reactions.
(4) Water consists of one oxygen and two hydrogen atoms so it is a compound. Therefore it can be broken down by chemical reactions.
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Answer details:
Grade: High School
Subject: Chemistry
Chapter: Elements, compounds, and mixtures
Keywords: substance, methane, argon, ammonia, water, element, compound, chemical reactions, broken down, simplest form, NaCl, CH4, carbon, sulfur, cobalt.
The answer is temperature
2. Cr
3. Mg
4. Pb
Answer : The correct option is, (2) Cr (Chromium)
Explanation :
The reactivity series of metal are arranged of the reactivity from the highest to the lowest. Reactivity series is used to determine the products of the single displacement reactions. In the single displacement reaction, the most reactive metal displaces the least reactive metal.
From the given reactivity series we conclude that there are two metal (Mg and Cr) are more reactive metal than the Ni and there are two metal (Pb and Cr) are less reactive metal than the Zn. So, the Cr (Chromium) is the metal which is more active than Ni and less active than Zn.
Hence, the correct option is, (2) Cr
The negative log of hydrogen or hydronium ions concentration gives the pH of the solution. The concentration of hydronium is more than the hydroxide ions.
The pH of the solution is the concentration of the hydrogen or the hydronium ion in the aqueous solution, whereas the concentration of the hydroxide ion in the solution gives the pOH.
Let the pH of the tea = 5 then,
The concentration of hydronium ion is calculated as:
The concentration of hydroxide ion is calculated as:
Calculating further:
Therefore, the concentration of the hydronium ion is much higher than that of the hydroxide ion.
Learn more about pH and pOH here: