General Chemistry Exam 3 Review

Solutions

Homogenous mixtures

Solute

component that is dissolved in a solution

Solvent

substance that does the dissolving

Dilute

has a low amount of solute

Concentrated

has a high amount of solute

Molarity (M)

moles of solute / liters of solution

mol/L 

Dilution

the process of making a substance less concentrated by adding more solvent

C₁V₁ = C₂V₂ or M₁V₁= M₂V₂

Concentrations and volumes of stock solution and new solutions are inversely proportional 

Ionic compounds, when dissolved, are called…

Salt solutions 

Electrolyte solutions

solutions that conduct electricity because they contain ions

Nonelectrolyte solutions

solutions that do not conduct electricity because they consist of neutral molecules

Strong electrolytes

completely disassociate into ions

Weak electrolytes

partial disassociation into ions

Nonelectrolytes

dissolve into water but do not form ions

Soluble

If a compound dissolves in water

Insoluable

If a compound doesn’t dissolve in water

Precipitation reactions 

chemical reaction where two soluble solutions are mixed and an insoluble solid, called a precipitate, forms and separates from the liquid

Precipitate

solid that forms and separates from the liquid solution 

Molecular equation

the equations showing the complete neutral formula for each compound in an aqueous solution 

Complete Ionic equations

shows all dissolved ionic compounds broken into their separate ions

Spectator ions

ions that don’t participate in chemical reactions, unchanged on both sides of the equation 

Net ionic equations

does not have spectator ions

Acids 

Molecular compounds that form H⁺ when dissolved, composed of H and one or more nonmetals 

Arrhenius Definition

Substance that produces H⁺ = acid

Polyprotic Acids

acids that contain more than one ionizable proton (H⁺) and release them sequentially 

Base

substance that produces OH^- in the aq solution 

Binary Acids

Have H⁺ and one other ion: HCl, HF

Oxyacid

Have H⁺ and contain oxygen: H₂SO₄, HNO₃

Name binary acid 

hydro + (nonmetal name) + ic acid 

Neutralization reaction 

when acid and base react 

Oxidation reduction reactions 

(redox reactions)

when electrons are transferred from one reactant to another 

Oxidized

atoms that loose electrons

Reduced

atoms that gain electrons

Energy

anything that has the capacity to do work

Work

a force acting over a distance

Heat 

Flow of energy caused by a difference in temperature

Kinetic energy

Energy of Motion

Thermal energy

Energy associated with temperature

Potential energy

stored energy

Energy = Work =

Force * Distance

KE = 

1/2(mass* velocity²)

Thermodynamics

study of energy and its interconversions

1st Law of Thermodynamics

energy is not created or destroyed, only transferred

System

the part of the universe being studied

Surroundings

everything else in the universe with which the system exchanges energy 

Endothermic reactions

absorb heat from the surroundings, making them feel cold

Exothermic reactions

release heat into the surroundings, making them feel hot

Change in energy…

Final amount - initial amount 

Internal energy

(E or U) the sum of kinetic and potential energies in a system 

Change in Energy 

q + w

Heat Exchange 

the transfer of thermal energy between two systems/substances due to a temperature difference

Temperature

measure of thermal energy within a sample (NOT HEAT!)

Thermal Equilibrium

Heat flowing from high temp.—> low temp. until both objects have the same temp. 

Heat capacity 

(C) is the quantity of heat absorbed 

Depends on amount of matter and type of metal 

q = C * change in T

Heat (J)

q = m* C_s * change in T

Specific Heat Capacity

amount of heat energy required to raise temp. of one gram a substance by 1 degree Celsius 

Molar Heat Capacity 

amount of heat energy required to raise temp.  of one mole a substance by 1 degree Celsius 

Heat transfer

energy exchange between materials as  a result of temperature change 

Thermal energy transfer

the movement of thermal energy from a hotter object or area to a cooler one due to a temperature difference

Pressure-Volume Work 

(PV Work) volume exchanged against external pressure 

work (w) =

-P * change in Volume

work_gas = 

External Pressure * Change of Volume in gas 

1 atm * L =

101.3 Joules

Enthalpy

(H) is the sum of internal energy of a system + PV

H = E + PV

H = E - W 

Enthalpy Change

heat involved in a reaction at constant pressure

Hess’s Law

total enthalpy change for a reaction is the same regardless of the path taken, no matter how many steps

Determining Enthalpies from Bond Energies