Sem 2 Vocab Review

Fill in the blank: ________ occurs when the forward and reverse reactions happen at the same rate, resulting in no net change in the concentrations of reactants and products. At this state, the system is stable, and the macroscopic properties remain constant.

• Equilibrium

• Sublimation

• Condensation

• Decomposition

What is the mass of one mole of a substance, measured in grams per mole (g/mol), and is numerically equal to the formula mass but expressed in grams? For example, the molar mass of water (H2O) is approximately 18.02 g/mol.

• Molar Mass

• Atomic Number

• Avogadro's Number

• Empirical Formula

Fill in the blank: ________ reactions release energy, usually in the form of heat, to their surroundings. In such reactions, the products have lower energy than the reactants. Examples include combustion and the freezing of water.

• Exothermic

• Endothermic

• Isothermal

• Photochemical

What is a Combustion Reaction? Fill in the blank: A combustion reaction is a chemical reaction in which a substance combines with ____ , releasing energy in the form of heat and light. This reaction often produces carbon dioxide and water as products, especially when hydrocarbons are involved.

• oxygen

• hydrogen

• nitrogen

• carbon

What is a Decomposition Reaction? Fill in the blank: A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more simpler substances. It can be represented by the general formula: ____ → ____ + ____.

• AB → A + B

• A + B → AB

• A + B → C

• AB + C → AC + B

What is the term for the sum of the atomic masses of sodium and chlorine in sodium chloride (NaCl), measured in atomic mass units (amu)?

• Formula Mass

• Molarity

• Empirical Formula

• Isotopic Mass

What is a ratio or fraction that expresses the equivalence between different units and is used for converting one unit to another? For example, the conversion factor for meters to centimeters is 100 cm/1 m.

• Conversion Factor

• Numerator

• Denominator

• Exponent

Fill in the blank: ________ explains how chemical reactions occur and why reaction rates differ. It states that for a reaction to take place, reactant particles must collide with sufficient energy and proper orientation. The energy required for an effective collision is known as the activation energy.

• Collision Theory

• Le Chatelier's Principle

• Boyle's Law

• Avogadro's Law

Fill in the blank: An ________ is a substance that increases the concentration of hydrogen ions (H⁺) in an aqueous solution. Acids typically have a sour taste, can turn blue litmus paper red, and react with bases to form salts and water. Common examples include hydrochloric acid (HCl) and sulfuric acid (H₂SO₄).

• acid

• base

• salt

• alkali

What is a Synthesis Reaction? Fill in the blank: A synthesis reaction is a type of chemical reaction in which two or more simple substances combine to form a more complex compound. It can be expressed by the general formula: ____ + ____ → ____.

• A + B → AB

• AB → A + B

• AB + CD → AD + CB

• A + B → A2B