Exam 2 Chemistry

What are aqueous solutions?

water is the solvent

Ionic compounds ________ _________ into ions in solution

dissociate completely

Most covalent compounds _______ ______ into ions in a solution,

Do not dissociate

What is dynamic chemical equillibrium?

both forward and reverse reactions are happening at the same rate

How do non-electrolytes react in solution?

Does not dissociate into ions, no electrcity conducted

How do weak electrolytes react in solution?

small portions of the compound ionizes to form ions

How do strong electrolytes react in solution?

completely dissociates/ionizes into ions, conducts electricty

what are acids?

A substance that produces H₃O⁺ or H⁺ ions when dissolved in H2O

Strong Acids ionize __________ into ions and are _______ electrolytes

completely, strong

Is this an example of a strong acid, weak acid, strong base, or weak base?: HCL (aq) + H₂O (l) > H₃O⁺ (aq) + Cl^- (aq)

strong acid

Is this an example of a strong acid, weak acid, strong base, or weak base?: HC₂H₃O₂(aq) + H₂O (l) H₃O+ (aq) + C₂H₃O₂^-(aq)

Weak acid

Weak acids _______ ionize to form _______ ions, _________ electrolytes

slighlty, few, weak

What is a base?

A base is a substance that produces OH^- when dissolved in water, many are strong electrolytes and ionic compounds

Weak bases do not contain _________ ions but produce them to a small extent in water. Weak bases are __________ electrolytes

OH^- . weak

Hydrochloric Acid

HCL

Hydrobromic Acid

HBr

Hydroiodic Acid

HI

Sulfuric Acid

H₂SO₄

Nitric Acid

HNO₃

Chloric Acid

HClO₃

Perchloric Acid

HClO₄

When ionic substances dissolve in water, the water molecules remove the ions and surround them in a process called

hydration

what are precipitation reactions?

double-displacement reaction to form an insoluble product

what is the precipitate in this: 2 NaI (aq) + Pb(NO3)₂ (aq) → 2 NaNO₃ (aq) + PbI₂(s)

PbI₂

what are spectator ions?

ions that do not participate in the reaction and are present on both sides of the reaction as the same species

What are acid base reactions (neutralization)

acid and base react together to form water: Strong acids/bases fully dissociate while weak acids/bases partially ionize in a solution

Is an acid a proton donor or acceptor? And base?

an acid is a proton donor and a base is a proton acceptor.

What are polyprotic acids

Each acid molecule has multiple protons to donat e

weak bases do not contain ________ but produce them to a small extent in water. weak bases are _______ _______

OH-, weak electrolytes

Acid-base equations always crates _________ and ____________

water and an ionic salt

Oxidization is the _________ of electrons

loss

Reduction is the ________ of electrons

gaining

What is the oxidation number?

the charge an atom would have if electrons were transfered completely

what is the reducing agent?

the species that donates the electrons and causes the other species to be reduced.

what is the oxidizing agent?

The species that accepts electrons and causes the other species to be oxidized.

The sum of oxidization states for a neutral compound should be? And a polyatomic ion

0, equal to net charge of polyatomic ion

Pure elements have an oxidization state of ________

0

Monoatomic ions have an oxidization state equal to ___________

their charge

In compounds, metals have positive oxidation state referring to ____________

their group number 1A and 2A

The oxidization state of fluorine is _______

-1

The oxidiation state of hydrogen is ______ unless with metal then it is _________

+1, different

The oxidization state of oxygen is _______ unless with peroxide (hydrogen) then it is __________

-2, -1

The oxidization state of halogen (7A) is typically _______ unless when with another halogen or oxygen

-1

The oxidization state of 6A is _______ and for 5A is _______

-2, -3

What is the half-reaction method for redox reactions

divides a redox reaction into its oxidization and reduction half-reactions

What is concentration?

used to represent the quanity of solute present in a given quantity of a solution

molarity =

moles over volume

percent by mass:

mass of solute/mass of solution x 100%

Dilution…

process of preparing a less concentrated solution from a more concentrated one

m₁v₁=m₂v₂

m1 is the concentration of the solution

v1 is the volume of the stock solution

m2 is the conc of the dilution

v2 is the total volume of dilution

what does gravimetric analysis find?

can be used with precipiation reactions to determine the amount of a certain ion in solution based on the amount of precipitate formed

what is an analyte

chemical of interest

what is a titrant

the chemical added gradually to react with the analyte

what is the indicator

chemical that indicates the endpoint of the reaction (color change)

what happens at the equivalence point of triations

moles of H+ ions = OH- ions

Redox triations are used to…

quanitatively determine the endpoint of a reaction

potentional energy is a _______ ______ meaning…

state function meaning it doesn’t matter how it was achieved

what are the types of potential energy?

chemical: potential energy stored within bonds or arrangements of atoms

electrostatic: potential energy that results from the interaction of charged particles

lattice: measure of an ionic compound’s stability, the greater the more stable

the charges of the ions are _______ proportuonal to the elecrostatic energy

directly

the size of the ions/distance between the ions is __________ proportional to the electrostatic energy

indirectly

if E_el < O, it indication __________ while E_el> O indicates _________

attraction, repulsion

The total energy of the universe is _________

constant

what is the system reffering to

the reactant and products in a chemial process

what is the surrounding

everything else (beaker, room,..)

Heat is the measure of…

the thermal energy that flows from a hotter to colder object

heat is proportional to _________

the temeprature of the sample and number of particles (extensive)

temperature determines the ___________ of heat fow. It is the measure of an object’s ___________. It does not depeond on ___________

direction, kinetic energy, amount of substance

What is thermochemistry

the study of the changes in energy as heat that accompany chemical reactions

what is the endothermic process?

process that absorbs thermal energy as heat

what is the exothermic process?

a process that gives off heat

In endothermic reactions, heat flows from _________ to _________ making surrounding feel ________ to touch

surroundings, system, cold

In exothermic reactions, heat flows from ________ to _______ and makes surroundings feel _________

system, surroundings, warm

Endothermic reactions have a ________ net energy change

positive

Exothermic reactions have a _______ net energy change

negative

Is the energy of the products or reactants higher for endothermic reactions? What about exotermic reactions?

endo: products are higher

exo: reactants are higher

open systems can..

exchan ge mass and energy

closed systems can…

transfer energy, but not mass

isolated systems can…

not transfer mass or energy

Energy released in one placed must be…

gained somewhere else

the overall change in a system’s internal energy is :

delta U= q+w

q is the heat

w is the work

when heat is absorbed q is _________

+

when heat is released q is ______

negative

when work is done on the system w is …

+

when work is done by the system w is …

-

What is enthalpy?

a thermodynamic property that measures the total heat content of a system at constant pressure

what does ΔH stand for?

change in energy for a system at constant pressure

What is the equation for enthalpy?

H= U+ PV

For any equation, we define the change in enthalpy as…

ΔH= H (products) - H (reactants)

What phase changes are endothermic?

freezing, condensation, deposition

what phase changes are exothermic?

melting, vaporization, sublimination

In an exothermic process the ΔH is…

positive

in an endothermic process ΔH is..

positive

Thermochemical equations show…

enthalpy changes along with mass relationships