Honors Chemistry: 2024-2025 Final Examination Study Guide

Flashcards for vocabulary review of honors chemistry topics including stoichiometry, ideal gasses, solutions, reaction kinetics, equilibrium, acids and bases, thermochemistry, and organic chemistry.

Law of Conservation of Mass

Matter is neither created nor destroyed in a chemical reaction.

Law of Conservation of Mass

The total mass of reactants equals the total mass of products.

Law of Conservation of Mass

The basis for balancing equations and calculating amounts in stoichiometry.

Balanced Chemical Equation

Provides the mole ratio between reactants and products.

Mole

The unit chemists use to count atoms, molecules, or formula units.

Molar Mass

The mass of one mole of a substance (g/mol).

Mole Ratio

The ratio of moles of any two substances in a balanced chemical equation.

Limiting Reactant

The reactant that gets completely used up in a chemical reaction.

Limiting Reactant

The reactant that determines the maximum amount of product that can be formed.

Excess Reactant

The reactant that is left over after the limiting reactant has been completely consumed.

Theoretical Yield

The maximum amount of product that can be formed from a given amount of reactants, calculated based on stoichiometry.

Actual Yield

The amount of product actually obtained from a chemical reaction in an experiment.

Percent Yield

A measure of the efficiency of a reaction, calculated as (Actual Yield / Theoretical Yield) x 100%.

Using STP

Convert between moles of a gas and volume of a gas.

Master Molar Mass Calculations

You will use this constantly in Stoichiometry.

Understand Mole Ratios

This is the heart of stoichiometry.

Use Dimensional Analysis (Factor-Label Method)

This systematic approach helps you set up and check your calculations, reducing errors.

Show Your Work

Even on multiple-choice questions, showing your work helps you catch mistakes and is essential for complex problems.

No Definite Shape or Volume

Gases expand to fill any container they occupy.

Highly Compressible

Due to large empty spaces between particles, gases can be easily compressed.

Low Density

Compared to liquids and solids, gases have very low densities.

Uniform Mixing (Diffusion)

Gases readily mix completely and uniformly with other gases.

Fluidity

Gases flow easily, like liquids.

Tiny Particles

Gases consist of tiny particles (atoms or molecules) that are far apart relative to their size.

Constant, Random Motion

Gas particles are in continuous, rapid, random motion and possess kinetic energy (KE).

Elastic Collisions

Collisions between gas particles and with the container walls are perfectly elastic, meaning no net loss of kinetic energy over time.

No Intermolecular Forces

There are no attractive or repulsive forces between gas particles.

Temperature & Kinetic Energy

The average kinetic energy of gas particles is directly proportional to the absolute temperature (in Kelvin).

Boyle's Law (P-V Relationship)

As pressure increases, volume decreases (at constant n, T).

Boyle's Law (P-V Relationship) Formula

P1V1=P2V2

Charles's Law (V-T Relationship)

As temperature increases, volume increases (at constant n, P).

Charles's Law (V-T Relationship) Formula

V1/T1=V2/T2

Gay-Lussac's Law (P-T Relationship)

As temperature increases, pressure increases (at constant n, V).

Gay-Lussac's Law (P-T Relationship) Formula

P1/T1=P2/T2

Avogadro's Law (V-n Relationship)

As moles increase, volume increases (at constant P, T).

Avogadro's Law (V-n Relationship) Formula

V1/n1=V2/n2

Combined Gas Law

Combines Boyle's, Charles's, and Gay-Lussac's laws.

Combined Gas Law Formula

P1V1/T1=P2V2/T2

Ideal Gas Law

Relates all four gas variables simultaneously.

Ideal Gas Law Formula

PV=nRT

Ideal Gas Law Variable

P = pressure

Ideal Gas Law Variable

V = volume

Ideal Gas Law Variable

n = number of moles

Ideal Gas Law Variable

R = Ideal Gas Constant

Ideal Gas Law Variable

T = temperature (in Kelvin)

Ideal Gas Constant (R)

The value of R depends on the units used for pressure and volume.

Ideal Gas Constant Value

R=0.08206 (L⋅atm)/(mol⋅K)

Ideal Gas Constant Value

R=8.314 J/(mol⋅K)

Gas Law Problems

First convert to Kelvin.

Gas Law Units

Pay close attention to units, especially for pressure and when choosing the correct R value.

Identify Constants

In gas law problems, determine which variables are constant to simplify the formula.

Solution

A homogeneous mixture of two or more substances.

Solute

The substance that is dissolved (present in a smaller amount).

Solvent

The substance that does the dissolving (present in a larger amount).

Suspension

A heterogeneous mixture where solid particles are large enough to settle out over time.

Colloid

A heterogeneous mixture with particles larger than those in a solution but smaller than those in a suspension.

Tyndall Effect

The scattering of light by suspended particles in a colloid or a suspension, making the beam of light visible.

Molarity (M)

Moles of solute per liter of solution.

Molarity Formula

M= moles of solute/liters of solution

Percent Concentration (% w/v)

Grams of solute per 100 milliliters of solution.

Dilution

The process of adding more solvent to a solution to decrease its concentration.

Dilution Formula

M1V1=M2V2

Ions in Solution

When ionic compounds (like salts) dissolve in water, they dissociate (break apart) into their individual ions.

Reaction Mechanism

A step-by-step description of how a chemical reaction occurs at the molecular level.

How Reaction Mechanisms Work

Reactants collide and form an intermediate or transition state.

How Reaction Mechanisms Work

The intermediate undergoes further reactions to form products.

How Reaction Mechanisms Work

Any catalysts used are regenerated.

Sufficient Energy

The collision must provide enough energy to overcome the activation energy barrier.

Proper Orientation

The molecules must collide in the correct orientation for bonds to break and form.

Favorable Conditions

Factors like concentration, temperature, and the presence of a catalyst can increase the likelihood of effective collisions.

Activated Complex

A temporary, high-energy state that forms during a chemical reaction when reactant molecules collide with sufficient energy and proper orientation.

Le Chatelier’s Principle

If a dynamic equilibrium is disturbed by changing conditions, the system shifts to counteract the disturbance and re-establish equilibrium.

Increase reactant

Shifts toward products to use up added reactant.

Decrease reactant

Shifts toward reactants to replace lost reactants.

Increase product

Shifts toward reactants to use up added product.

Decrease product

Shifts toward products to replace lost products.

Increase pressure (decrease volume)

Shifts toward the side with fewer moles of gas.

Decrease pressure (increase volume)

Shifts toward the side with more moles of gas.

If moles of gas are equal on both sides

No effect on equilibrium.

Arrhenius Definition of Acids and Bases

An acid is a source of H+ ions in water and a base is a source of OH− ions in water.

Brønsted-Lowry Definition of Acids and Bases

An acid is a species that can donate a proton (H+) and a base is a species that can accept a proton (H+).

pH Calculation

pH=−log[H+]

pOH Calculation

pOH=−log[OH−]

pH and pOH Relationship

pH+pOH=14

Calorie

The amount of heat needed to raise 1g of water by 1°C.

Conduction

Direct transmission of heat/electricity without material movement.

Calorimeter

Instrument to determine heat capacity.

Critical Point

Existing as a supercritical fluid where liquid and gas phases are indistinguishable.

Enthalpy (ΔH)

A measure of heat change in a reaction.

Exothermic vs. Endothermic

Relate ΔH to heat release or absorption.

Bond Energy

Breaking bonds requires energy.

Bond Energy

Forming bonds releases energy.

ΔH Calculation Formula

ΔH=Σ(bond energies of bonds broken)−Σ(bond energies of bonds formed).

Heat Calculations with Phase Changes

Remember to use appropriate specific heat capacities for each phase and enthalpy of fusion/vaporization for phase changes.

Calorimetry Problems (Heat Exchange)

heat lost by one substance equals heat gained by another (qlost=−qgained).

Saturated Hydrocarbons

These contain only single carbon-carbon bonds.

Unsaturated Hydrocarbons

These contain at least one carbon-carbon double or triple bond.

Hydroxyl

-OH

Aldehyde

-CHO

Ketone

R-CO-R'