Chemistry – Ions and salts -Exam Special

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Chemistry

Ions and salts

 

1-An ion is a charged species, an atom or a molecule, that has lost or gained one or more electrons.

2-When an atom loses an electron and thus has more protons than electrons, the atom is a positively charged ion or cation.

3-When an atom gains an electron and thus has more electrons than protons, the atom is a negatively charged ion or anion.

4- Examples of polyatomic ions that do not split up during acid-base reactions are hydroxide (OH−) and phosphate (PO43−).

5- Arrhenius theory states than an acid is a substance that produces hydronium ions when it is dissolved in water, and a base is one that produces hydroxide ions when dissolved in water.

6- Lewis acid-base theory is based on the formation of new chemical bonds.

7- Arrhenius definition of acidity is pH, which is a measurement of the hydronium ion concentration in a solution, as expressed on a negative logarithmic scale.

8-Substances that have the ability to oxidize other substances are said to be oxidative and are known as oxidizing agents, oxidants or oxidizers.

9- Substances that have the ability to reduce other substances are said to be reductive and are known as reducing agents, reductants, or reducers.

10-Oxidation is better defined as an increase in oxidation number, and reduction as a decrease in oxidation number.

11-Avogadro’s law (sometimes referred to as Avogadro’s hypothesis or Avogadro’s principle) is an experimental gas law relating volume of a gas to the amount of substance of gas present.

12-Boyle’s law (sometimes referred to as the Boyle–Mariotte law, or Mariotte’s law ) is an experimental gas law that describes how the pressure of a gas tends to increase as the volume of the container decreases.

13-Charles’s law (also known as the law of volumes) is an experimental gas law that describes how gases tend to expand when heated.

14-The combined gas law is a gas law that combines Charles’s law, Boyle’s law, and Gay-Lussac’s law.

15-Gay-Lussac’s law can refer to several discoveries made by French chemist Joseph Louis Gay-Lussac and other scientists pertaining to thermal expansion of gases and the relationship between temperature, volume, and pressure.

16-An ideal gas is a theoretical gas composed of many randomly moving point particles whose only interaction is perfectly elastic collision.

17-One mole of an ideal gas has a volume of 22.4 litres at STP as defined by IUPAC.

18-Many gases such as nitrogen, oxygen, hydrogen, noble gases, and some heavier gases like carbon dioxide can be treated like ideal gases within reasonable tolerances.

19-Cations and anions can form a crystalline lattice of neutral salts, such as the Na+ and Cl− ions forming sodium chloride, or NaCl.

20-According to the IUPAC gold book, a chemical reaction is “a process that results in the interconversion of chemical species.

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