Ions, Chemical Equations, and Reactions PDF

Ions, Chemical Equations, and Reactions Ions and Ionic Compounds An ion is an atom that has a positive or negative charge due to the loss or gain of electrons Formation of Ions Atoms can lose or gain electrons to become ions Posi...

Ions, Chemical Equations, and Reactions Ions and Ionic Compounds An ion is an atom that has a positive or negative charge due to the loss or gain of electrons Formation of Ions Atoms can lose or gain electrons to become ions Positive ions are called cations, and negative ions are called anions Examples: Na+ (cation), Cl- (anion) Naming Ionic Compounds Rules for naming ionic compounds: Name the metal (cation) first Name the non-metal (anion) second, changing its ending to "-ide" Example: NaCl = Sodium chloride Chemical Equations Parts of a chemical equation: Reactants (left side) Products (right side) Arrow (→) separating reactants and products Conservation of Mass Law of Conservation of Mass: In a chemical reaction, matter is neither created nor destroyed; it can only change forms Importance: Explains why we need to balance equations Balanced Equations An equation is balanced when there are the same number of each type of atom on both sides: Example: H2 + O2 → H2O (unbalanced) Example: 2H2 + O2 → 2H2O (balanced) Exothermic and Endothermic Reactions Exothermic reactions release heat to the surroundings Endothermic reactions absorb heat from the surroundings Chemical bonds are broken and formed in both types Review Questions 1.What is an ion? 2.Give an example of a cation and an anion. 3.What are the parts of a chemical equation? 4.State the law of conservation of mass. 5.What's the difference between exothermic and endothermic reactions? Answers 1.An atom with a positive or negative charge due to loss or gain of electrons 2.Cation: Na+, Anion: Cl- 3.Reactants, products, and an arrow 4.Matter is neither created nor destroyed in a chemical reaction 5.Exothermic reactions release heat, while endothermic reactions absorb heat