Your answer should be C.) +2. "All the elements in Group 2 have two electrons in their valence shells, giving them an oxidation state of +2."
Credits: https://chem.libretexts.org/Core/Inorganic_Chemistry/Descriptive_Chemistry/Elements_Organized_by_Blo...
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A bike rusting is an example of a chemical
change since rusting is a chemical reaction. New substances are formed from
this reaction. On the other hand, other choices given are just physical changes
because only the shape or the physical form of the substances are being
changed. An example of a physical change is cutting a paper.
Answer:
The mass of the atom, its atomic mass, depends upon the sum of the number of protons and the number of neutrons present in the nucleus. Since the properties of the electrons depend upon the number of protons in the nucleus of an atom, each different atomic number corresponds to a qualitatively different kind of atom.
Since the heat of solution of KI is 20.3 kJ/mol, the answer to the question is a. Exothermic, ΔH is positive
There are two types of chemical reactions namely exothermic and endothermic reaction.
- For exothermic reactions, heat is released. So, ΔH is positive
- For endothermic reactions, heat is absorbed. So, ΔH is negative
Given the heat of solution of KI as 20.3 kJ/mol.
Since it is positive, the reaction is exothermic and ΔH is positive
Since the heat of solution of KI is 20.3 kJ/mol, the answer to the question is a. Exothermic, ΔH is positive
Learn more about heat of solution here:
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