Chemistry Questions et reponses d'entretien
Question 11. Define the terms cation and anion.
A cation is a positively charged ion formed by losing electrons, while an anion is a negatively charged ion formed by gaining electrons.
Example:
Sodium (Na+) is a cation, while chlorine (Cl-) is an anion.
Question 12. What is the concept of a buffer solution?
A buffer solution resists changes in pH when an acid or base is added. It contains a weak acid and its conjugate base (or a weak base and its conjugate acid).
Example:
Acetic acid (CH3COOH) and acetate (CH3COO-) form a buffer system.
Question 13. Explain the concept of photochemical reactions.
Photochemical reactions are chemical reactions that are initiated by the absorption of light. They often involve the breaking or formation of bonds.
Example:
Photosynthesis is a photochemical process where light energy is used to convert carbon dioxide and water into glucose and oxygen.
Question 14. What is the purpose of the periodic trends in the periodic table?
Periodic trends describe the variations in atomic properties such as atomic radius, ionization energy, and electronegativity as one moves across a period or down a group in the periodic table.
Example:
Atomic radius generally decreases across a period and increases down a group.
Question 15. Define the concept of isoelectronic species.
Isoelectronic species are different chemical species that have the same number of electrons.
Example:
O2-, F-, and Na+ are isoelectronic because they all have 10 electrons.
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