Answer: 2. cannot be an element.
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: methane 
Thus as it can be decomposed into its constituent elements, it is a compound.
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.
Thus methane cannot be an element.
Answer:
K2Cr2O7
Explanation:
Solubility refers to the amount of substance that dissolves in a given mass or volume of solvent. There are several units of solubility applicable in different areas.
Solubility is dependent on temperature. The solubility curve is a graphical representation of the dependence of solubility on temperature for different chemical species.
If we study the solubility curve closely, we will see that K2Cr2O7 has the highest solubility at 100°C. This means that if the trends continue, this substance will also have the highest solubility at 120°C.
Metal because it’s more stronger
The higher the greenhouse gases, the higher the ocean temperature
"The ocean absorbs most of the excess heat from greenhouse gas emissions, leading to rising ocean temperatures"
hope this helps :)
"Only electrons are involved in chemical reactions" is the statement among the following choices given in the question that is the <span>best explanation for chemical reactions not to produce radioactive particles. The correct option among all the options that are given in the question is the third option or option "C". </span>
