Chemical Reactions Types and Equations

Chemical Reactions

• Types of Chemical Reactions:
  • Synthesis (Combination) Reaction: 2 or more substances combine to form a new compound
  • Decomposition Reaction: 1 substance breaks down into 2 or more simpler substances
  • Replacement (Substitution) Reaction: 1 element replaces another element in a compound
  • Combustion Reaction: a substance reacts with oxygen to produce heat and light
• Chemical Reaction Equations:
  • Reactants: substances on the left side of the equation
  • Products: substances on the right side of the equation
  • Arrow (→) indicates direction of reaction
  • Coefficients: numbers in front of formulas to balance the equation
• Chemical Reaction Rates:
  • Factors Affecting Reaction Rate:
    • Concentration
    • Temperature
    • Surface Area
    • Catalysts
  • Rate of Reaction: speed at which reactants are converted to products

Acids and Bases

• Arrhenius Definition:
  • Acids: substances that produce H+ ions in solution
  • Bases: substances that produce OH- ions in solution
• Brønsted-Lowry Definition:
  • Acids: substances that donate H+ ions (protons)
  • Bases: substances that accept H+ ions (protons)
• pH Scale:
  • Measures acidity/basicity of a solution
  • pH 7: neutral (neither acidic nor basic)
  • pH < 7: acidic
  • pH > 7: basic
• Strong and Weak Acids/Bases:
  • Strong Acids/Bases: completely dissociate in solution
  • Weak Acids/Bases: partially dissociate in solution
• Examples of Acids and Bases:
  • Acids: HCl, H2SO4, CH3COOH
  • Bases: NaOH, KOH, NH3

Chemical Reactions

• Chemical reactions involve the transformation of one or more substances into new substances.
• There are four main types of chemical reactions:
  • Synthesis reactions: two or more substances combine to form a new compound.
  • Decomposition reactions: one substance breaks down into two or more simpler substances.
  • Replacement reactions: one element replaces another element in a compound.
  • Combustion reactions: a substance reacts with oxygen to produce heat and light.
• Chemical reaction equations represent the reactants, products, and direction of the reaction.
  • Reactants are listed on the left side of the equation.
  • Products are listed on the right side of the equation.
  • The arrow (→) indicates the direction of the reaction.
  • Coefficients are used to balance the equation.

Chemical Reaction Rates

• Factors that affect the rate of a chemical reaction include:
  • Concentration
  • Temperature
  • Surface area
  • Catalysts
• The rate of a chemical reaction is the speed at which reactants are converted to products.

Acids and Bases

• Acids and bases are classified based on their ability to donate or accept protons.
• According to the Arrhenius definition:
  • Acids produce H+ ions in solution.
  • Bases produce OH- ions in solution.
• According to the Brønsted-Lowry definition:
  • Acids donate H+ ions (protons).
  • Bases accept H+ ions (protons).
• The pH scale measures the acidity or basicity of a solution.
  • pH 7 is neutral (neither acidic nor basic).
  • pH < 7 is acidic.
  • pH > 7 is basic.
• Acids and bases can be strong or weak, depending on their ability to dissociate in solution.
  • Strong acids and bases completely dissociate in solution.
  • Weak acids and bases partially dissociate in solution.
• Examples of acids include:
  • HCl
  • H2SO4
  • CH3COOH
• Examples of bases include:
  • NaOH
  • KOH
  • NH3

Chemical Reactions

Types of Chemical Reactions:

• Synthesis reaction occurs when two or more substances combine to form a new compound.
• Decomposition reaction involves a single compound breaking down into two or more substances.
• Replacement reaction occurs when one element replaces another element in a compound.
• Combustion reaction is a reaction between a substance and oxygen, often releasing heat and light.
• Neutralization reaction occurs when an acid reacts with a base to form a salt and water.

Chemical Equation:

• A chemical equation is a representation of a chemical reaction using chemical formulas and symbols.
• Reactants are written on the left, products on the right, and the arrow (→) indicates the direction of the reaction.
• Coefficients are used to balance the equation, ensuring that the number of atoms of each element is the same on both sides.

Factors Affecting Reaction Rates:

• Increasing the concentration of reactants can increase the reaction rate.
• Higher temperatures can increase the reaction rate.
• Increasing the surface area of reactants can increase the reaction rate.
• Catalysts are substances that speed up the reaction without being consumed by it.

Acids and Bases

Definitions:

• An acid is a substance that donates a proton (H+ ion).
• A base is a substance that accepts a proton (H+ ion).

pH Scale:

• pH is a measure of the concentration of hydrogen ions (H+) in a solution.
• pH 7 is neutral, pH < 7 is acidic, and pH > 7 is basic.

Types of Acids and Bases:

• Strong acids completely dissociate in water, releasing all H+ ions.
• Weak acids partially dissociate in water, releasing some H+ ions.
• Strong bases completely dissociate in water, releasing all OH- ions.
• Weak bases partially dissociate in water, releasing some OH- ions.

Acid-Base Reactions:

• Neutralization reaction occurs when an acid reacts with a base to form a salt and water.
• Acid-base indicators are substances that change color in response to changes in pH, used to determine the acidity or basicity of a solution.