Unit 5 and 6 Flashcards
Homogeneous mixture of two or more substances
Solution
The most abundant component of a solution in terms of moles
Solvent
Any component in a solution other than the solvent.
Solute
Water is a (blank) but aqueous describes (blank)
Solvent, solution
A substance that dissociates into ions when it dissolves enhancing the conductivity of the solvent
Electrolyte
A substance that dissociates completely into ions when it dissolves in water
Strong electrolyte
What is an example of a strong electrolyte?
Sodium chloride
A substance that does not dissociate into ions and therefore does not enhance the conductivity of water when dissolved
Non electrolyte
A substance that only partly dissociates into ions when it dissolves in water
Weak electrolyte
Few ions =
Poor conductivity
What is an example of a weak electrolyte?
Acetic acid
A solution in which the solvent is water
Aqueous
Interaction of water with ions
Positive H atoms attracted to (blank)
Negative O atom attracted to (blank)
Negative ion (anion) Positive ion (cation)
The feature of water relates to the concept of (blank)
Polarity
How do we know ions are present in aqueous solutions?
Solutions conduct electricity
Homogeneous mixture of two or more substances
Solution
What two things is a solution composed of?
Solute and solvent
Substances that ionize in water to form electrically conducting solutions
Electrolytes
Dissociates completely in solution
Strong electrolyte
(Blank) conducts electricity
Strong electrolyte
Dissociate partially in solution
Weak electrolyte
Dissolve in solution but do not ionize
No electrolytes
What are two examples of nonelectrolytes?
Ethanol and sugar
When oxides of sulfur, nitrogen, or other Nonmetals dissolve in water, they produce (blank)
Hydrogen ions
A H+ bonded to a molecule of water, H2O
The form in which the hydrogen ion is found in an aqueous solution
Hydronium ion (H3O+)
Proton donor
Acid
Proton acceptor
Base
Reaction that takes place when an acid reacts with a base and produces a solution of salt in water
Neutralization
The product of a neutralization reaction- made up of the cation of the base in the reaction plus the anion of the acid
Salt
A balanced equation describing a reaction in solution in with the reactants and products are written as undissociated molecules
Molecular equation
A balanced equation that shows all the species, both ionic and molecular, present in a reaction occurring in aqueous solution
Overall ionic equation
A balanced equation that describes the actual reaction taking place in aqueous solution; it is obtained by eliminating the spectator ions from the overall ionic equation
Net ionic equation
An ion that is present in a reaction vessel when a chemical reaction takes place but is unchanged by the reaction
Spectator ion
The reaction of water with another material
Hydrolysis
An acid that completely dissociates into ions in aqueous solution
Strong acids
An acid that only partially dissociates in aqueous solution and has a limited capacity to donate protons to the medium
Weak acid
A base that completely dissociates into ions in aqueous solution
Strong base
A base that only partially dissociates in aqueous solution and has a limited capacity to accept protons
Weak base
A substance that can behave as either a proton acceptor or proton donor
Amphiprotic
An analytical method for determining the concentration of a solute in a sample by reacting the solute with a standard solution of known concentration
Titration
The standard solution added to the sample in a titration
Titrant
Solution of known concentration used in titrations
Standard solution
A solid product formed from a reaction in a solution
Precipitate
A reaction that produces an insoluble product upon mixing two solutions
Precipitation reaction
(Blank) can be used to synthesize water-insoluble salts
Precipitation reactions
Common minerals that are often formed with anions that lead to insolubility
Sulfides, carbonates, oxides, hydroxides
A substance that produces hydrogen ions in solution
Acid
A substance that produces hydroxide ions in solution
Base
An acid ——- (blank) in water
H+
(Blank) are strong electrolytes and are completely ionized
Strong acids
(Blank) are weak electrolytes and only partially ionize
Weak acids
What is he chemical produced in the largest quantity in the US
Sulfuric acid
Acid that can furnish more than one proton
Polyprotic acid
Base —–(blank) in water
OH
(Blank) are strong electrolytes and are completely ionized
Strong bases
An important weak base
Ammonia (NH3)
Four steps to writing net ionic equation
1) write a balanced chemical equation
2) write a complete ionic equation
3) identify spectator ions
4) write the net ionic equation
The amount of solute in a particular amount of solvent or solution
Concentration
The concentration of a solution expressed in moles of solute per liter of solution
Molarity
A concentrated solution of a substance used to prepare solutions of lower concentration
Stock solution
The process of lowering the concentration of a solution by adding more solvent
Dilution
Driving force of a net ionic equation
Formation of an insoluble compound, a precipitate gas forming reaction
In acid base reaction the driving force is
The formation of water
A way to express acidity- the concentration of H+ in a solution
pH
Acidic solution pH
<7
Neutral solution pH
7
Basic solution pH
> 7
The medium in which a solute is dissolved to form a solution
Solvent
The substance dissolved in a solvent to form a solution
Solute
Amount of solute in a solution is given by its concentration
Solution concentration
Molarity (M)
Moles of solute / liter of solution
Concentration M =
moles/ volume
Important point in dilution problems
Moles in initial solution = moles in final solution
Dilution equation
M(initial) x V (initial) = M (final) x V (final)
Millimolarity
Millimoles of solute / L of solution
Parts per million (ppm)
(Mass of substance / mass of sample)x 10^6
Parts per billion
(Mass of substance / mass of sample)x 10^9
A solution that contains the maximum concentration of a solute possible at a given temperature
Saturated solution
The maximum amount of a substance that dissolves in a given quantity of solvent at a given temperature
Solubility
Increase in temp = blank solubility of solids in water
Greater
A solution that contains more than the maximum quantity of solute predicted to be soluble in a given volume of solution at a given temperature
Supersaturated solution
Process by which one ion is displaced by another
Ion exchange
What is ion exchange important in?
Water purification
Neutral crystalline minerals or synthetic materials consisting of 3D networks of channels that contain sodium for other 1+ cations
Zeolite
All zeolites have a rigid (blank) structure
3D
Combination reactions of oxygen with Nonmetals such as carbon, sulfur, and nitrogen produce
Volatile oxides
Oxidation
Increase in oxygen
Reduction
Decrease in oxygen
A chemical changes in which a species loses electrons
Oxidation
The ON increases
Oxidation
The ON decreases
Reduction
A chemical change in which a species gains electrons
Reduction
Change in ON reflects the change in (blank) associated with an atom or ion
of electrons
A positive or negative # based on the number of electrons an atom gains or loses when it forms an ion, or that it shares when it forms a covalent bond with another element
Oxidation number or state
ON of atoms in neutral molecule sum
Zero
ON of atoms in ion sum to
Charge on ion
Each atom in pure element has an ON # of
0
In monatomic ions, the ON is the charge (blank)
ON the ion
In compounds containing fluorine and 1+ elements, ON is
-1
In most compounds the ON of hydrogen is (blank) and oxygen is (blank)
1+
2-
ON of metal hydrides
-1
ON of O in peroxide ion (O2_^2)
-1
A substance in a redox reaction that contains the element being reduced
Oxidizing agent
Electron acceptor
Oxidizing agent
A substance in a redox reaction that contains the element being oxidized
Reducing agent
Electron donor
Reducing agent
One of the two halves of an oxidation- reduction reaction
Half reaction
Step 1 to balance redox reaction
1) write one equation for the oxidation half reaction and a separate equation for the reduction half reaction
Step 2 to balance redox reaction
Balance the # of particles in each half reaction
Step 3 to balance redox reaction
Balance the charge in each half reaction (always ADD electrons)
Step 4 to balance redox reaction
Multiply each half-reaction by the appropriate whole #
Step 5 to balance redox reaction
Add the the two half reactions to generate the equation representing the redox reaction
A qualitative ordering of the oxidizing ability of metals and their cations
Activity series
A chemical equation describing the redox reaction in nature will be balanced when
1) the # of atoms of each element on both sides of the reaction are the same
2) the total charges on each side of the reaction arrow are the same
General approach to solution stoichiometry problem
Mass zinc- moles zinc- stoichiometric factor - moles HCl- volume or mass HCl
Steps to solve a solution stoichiometry problem
1) write the balanced equation
2) calculate the moles of Zn
3) use the stoichiometric factor
4) calculate the volume of HCl required
Acronym for oxidation reduction reactions
OIL-RIG
Oxidation involves (blank) of electrons
Loss
Reduction involves (blank) of electrons
Gains
6 rules for assigning oxidation states
1) the oxidation state of an atom in its natural form is 0
2) simple ions = oxidation # = charge on ion
3) oxygen has a oxidation # of 2- in compounds
4) oxidation # of H- +1
5) Fluorine always has an oxidation # of -1 in compounds
6) sum of ON in neutral compound =0
Sum of ON of a polyatomic ion = charge on ion
Redox reactions are characterized by (blank) between an electron donor and electron acceptor
Electron transfer
Increase in ON of some element
Oxidation
Decrease in ON of some element
Reduction
The point in a titration at which the # of moles of titrant added is stoichiometrically = to the # of moles of the substance being analyzed
Equivalence point
The point in a titration that is reached when just enough standard solution has been added to cause the indicator to change color
End point
Law of thermodynamics
Energy is neither created nor destroyed during chemical reactions
The chemical equation of a reaction that includes energy as a reactant or product
Thermochemical equation
Describes whether energy is absorbed or released when reaction occurs
Thermochemical equation
A form of energy required to move an object through a given distance
Work
The study of energy and its transformations
Thermodynamics
The study of the relation between chemical reactions and changes in energy
Thermochemistry
Process by which energy moves from a warmer object to a cooler object
Heat transfer
Energy transferred between objects because different temps
Heat
A condition in which temperature is uniform throughout a material and no energy flows from one point to another
Thermal equilibrium
Work =
Force x distance
Energy stored in an object because of its position
Potential energy
Potential energy equation
PE = mass x g (acceleration due to gravity) x h (vertical distance)
A property of an entity based solely on its chemical or physical state or both, but not how it achieved that state
State function
State function does not depend on
How object gets to a particular point
The energy of an object in motion due to its mass (m) and its speed (u)
Kinetic energy
Energy cannot be created nor destroyed but can be converted from one form into another
Law of conservation of energy
The kinetic energy of atoms, ions, and molecules
Thermal energy
Increase in particles = increase in
Thermal energy
Energy a particle has because of its electrostatic charge and its position relative to another particle
Electrostatic potential energy (Eel)
Electrostatic energy is directly proportional to the product of the charged of the particles and inversely proportional to the distance between them
Coulombic interaction
A lower electrostatic potential energy corresponds to
Greater stability
The part of the universe that is the focus of a thermochemical study
System
Everything that is not part of the system
Surroundings
A system that exchanges neither energy nor matter with the surroundings
Isolated system
A thermos bottle containing hot soup with the lid screwed on tightly
Isolated system
A system that exchanges energy but not matter with the surroundings
Closed system
A cup of hot soup with a lid
Closed system
A system that exchanges both energy and matter with the surroundings
Open system
An open cup of hot soup
Open system
Energy flows from a system into its surroundings
Exothermic
(Blank) process is a combustion reaction
Exothermic
Energy flows from the surroundings into the system
Endothermic process
Ice cubes in warm water = (blank) process
Endothermic process
Releases energy = (blank) process
Exothermic
Absorbs energy = (blank) process
Endothermic
System loses energy to its surroundings
Exothermic
System gained energy from surroundings
Endothermic
Q
Exothermic
Q>O
Endothermic
The sum of all the kinetic and potential energies of all the components of a system
Internal energy (E)
Delta E =
E final - E initial
Reducing agents are electron
Donors
Reducing agents get
Oxidized
Oxidizing agents are electron
Acceptors
Oxidizing agents get
Reduced
Represent two parts of a redox reaction
Half reactions
A technique in which one solution is used to analyze another
Titration
Procedure to determine the concentration of a solution in a titration
Standardization
Occurs when exact stoichiometric amounts of both reagents have been added in a titration
Equivalence point
Steps to find concentration
1) balance the equation
2) calculate amount of (blank)
3) calculate amount of (blank) required
4) calculate concentration
The study of energy and its inter conversions
Thermodynamics
Capacity to do work or transfer heat
Energy
Energy transferred between two objects due to a temperature difference between them
Heat
The energy required at a constant pressure to raise the temperature of 1 mole of a substance by 1 degree C
Molar heat capacity
Q =
M C dT
The energy required to raise the temperature of 1g of a substance 1 degree C at constant pressure
Specific heat
The quantity of energy needed to raise the temperature of a particular object 1 degree C at constant pressure
Heat capacity
The energy required to convert 1 mole of a solid substance at its melting point into the liquid state
Molar heat of fusion (delta Hfus)
Enthalpy change
Q = ndeltaHfus
The energy required to convert 1 mole of a liquid substance at its boiling point to the vapor state
Molar heat of vaporization (deltaHvap)
System takes in energy = blank value
+
Ability of water to absorb large quantities of energy
Heat sink
To calculate the enthalpy change that takes place when 1 g of methane or 1 g of propane burns in air, producing CO2 and liquid water, we
Divide the absolute value of change in reaction for each reaction by the mm of hydrocarbon
The energy released during the complete combustion of 1 g of a substance
Fuel value
As the # of carbon atoms/ molecules increases, the hydrogen to carbon ratio
Decreases
The amount of energy released during the complete combustion of 1 liter of a liquid fuel
Fuel density
The quantity of energy produced when a material consumed by an organism for sustenance is burned completely
Food value
A condition in which the system and its surroundings are at the same Temp and heat transfer stops
Thermal equilibrium
The collection of molecules we are studying
System
Results in the evolution of heat
Heat flows from system to surroundings
Exothermic reactions
Absorbs energy
Energy flows into system from surroundings
Endothermic reactions
Heat required to raise temp of 1 g of H2O by 1 degree C
1 calorie
1000 calorie
1 kc
1 kc
1 kcal
Amount of energy required to raise an objects temperature by 1 degree C
Heat capacity
The heat capacity per gram of substance
Specific heat capacity
Problems involving heat transfer can be approached by assuming the sum of the heat changes within a given substance is zero
Complex heat transfer
The amount of energy necessary to raise the temperature of 1 g of water by 1 degree C
Calorie
The total increase in the internal energy of a closed system is the
Sum of the work done on it (w) and any other energy (q) gained
Q + w
The energy gained or lost by a system must equal the energy lost or gained by the surroundings
First law of thermodynamics
Work done by a system on its surroundings internal energy (blank)
Decreases
The work associated with the expansion or compression of a gas
Pressure-volume (PV work)
System heated by surroundings (q blank)
> O
Work done by system (w blank)
Energy transferred from system to surroundings (q blank)
Heat absorbed by an endothermic process or given off by an exothermic process occurring at constant pressure
Enthalpy change (delta H)
Sum of the internal energy and the pressure to volume product of a system
Enthalpy (H)
All the energy (heat and work) exchanged by the system with surroundings
Delta E
Only q, heat exchanged at constant pressure
Delta H
Energy flows out of system
Endothermic
Endothermic, q and H
Q -
Delta H
Heat flows into system
Exothermic
Exothermic, q and H
Q+
h>O
The standard enthalpy of reaction delta Hrxn for a reaction that is the sum of two or more reactions is equal to the sum of the delta H run values of the constituent reactions
Hess’s law
The capacity to do work or transfer heat
Energy
Thermal energy transferred from a warmer to a cooler object
Heat
Mechanical energy that moves an object from one place to another
Work
Heat into system = blank q
+
Heat out of system equals blank q
-
Work done on system
+
Work done by system
-
Heat transfer in
Endothermic
Heat transfer out
Exothermic
Work done on system
+w
Work done by system
-w
Heat content of a substance at constant pressure
Enthalpy
If Hfinal > H initial
Change in H- endothermic +
If H final < H initial then
Change in H - exothermic
Formation of water endothermic or exothermic
Exothermic
If a reaction is the sum of two or more reactions, the net delta H is the sum of the delta Hs of each reaction
Hess’s law
Property that is independent of pathway
State function
The measurement of the quantity of heat transferred during a physical change or chemical process
Calorimetry
A device used to measure the absorption or release of energy by a physical change or chemical process
Calorimeter
The energy absorbed or given off by a chemical reaction = heat of reaction
Enthalpy of reaction
A constant volume device used to measure the energy released during a combustion reaction
Bomb calorimeter
Heat capacity of a calorimeter
Calorimeter constant
The enthalpy change of a formation reaction- also called standard heat of formation
Standard enthalpy of formation
A reaction in which 1 mole of substance is formed from its component elements in their standard states
Formation reaction
The most stable form of a substance under 1 bar pressure and some specified temperature
Standard state
The energy associated with a reaction that takes place under standard conditions
Standard enthalpy of reaction
More negative the heat of formation of a subsgance, the (blank)
More stable
Change in Hrxn
Sum of nproducts -sum of nreactants
Science of measuring heat
Calorimetry
Device used to experimentally determine the heat associated with a chemical reaction
Calorimeter
