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#separator:tab #html:true Chemistryinvestigation of the atoms and molecules that make up our body and the world around us Subatomic particlesprotons, neutrons, and electrons Protons<ul><li>found within the nucleus and have an amount of charge eqaul to the fundamental unit of charge (e=1.6x10-19C).</li><li>Mass of a proton is 1 amu (one atomic mass unit)</li><li>ID the element; Z is the atomic number= number of protons</li></ul> Neutrons<ul><li>neutral</li><li>have a slightly larger mass than protons. However, it is negligible in most cases.</li><li>With protons make up the mass number (A) which is the number of protons and neutrons</li><li>Elements occuring in natural environment can have a different numbers of neutrons; these are called isotopes.</li><li>AZX is a convention of describing the properties of an atom/ element. For example isotope 146C has still 6 protons bc that IDs the element. However the number of neutrons is different </li><li>Protium: H with one proton</li><li>Deuterium: H with one proton one neutron</li><li>Tritium: H with one proton and 2 neutrons</li></ul> Electrons<ul><li>I would call them chemical currency  </li><li>move through the space surrounding the nucleus and are associated with varying energy levels </li><li>have the same magnitude of a charge to that of a proton but with opposite sign</li><li>mass of electron is 1/2000 mass of a proton</li><li>due to a small mass, attractive electrostatic forces are way stronger than the gravitational forces of attraction based on their masses.</li><li>move around various distances which correspond to the level of electrical potential energy ( closer to the nuicleus- lower energy; further away- higher energy)</li><li>valence electrons- electrons that have higher interactions with the surrounding as opposed to the interactions with nucleus.</li><li>neutral state -> electrons=protons</li></ul> Atomic Mass Atomic mass varries on the number of subatomic particles and it mostly corresponded with the Mass number (A) Size of the atomic mass unit<ul><li>1/12 the mass of carbon-12 atom</li><li>1.66x10-24g</li></ul> Atomic Weight<ul><li>The weighted average of these different isotopes</li><li>half-life ->marker of stability; longer-lasting isotopes more abundant</li></ul> Problem Chapter 1-  Determination of Subatomic Particles (nickle-58) *look at PSE, nickle has an atomic number of 28. Atomic number is a number of protons and that is important bc protons ID the element thus it can't be changed. Subtracted with the given mass number bc the mass number is protons plus electrons. You will get that there are 28 protons and 30 neutrons. Since the element is neutral (no other signs) you can conclude that it will have the same number of protons and the same number of electrons which is 28. Answer e:28 p:28 n:30 Problem Chapter 2-  Determination of Subatomic Particles (nickle-60; +2 cation)Same as before, you know that on PSE the number of protons will be 28 which is denoted by the atomic number. Use this and subtract from the mass number to get the number of neutrons. So there is still 28 protons and now 32 neutrons. THIS ELEMENT ISN'T NEUTRAL, and if proton IDs the element that is not gonna change, neutron is given to us by the mass number. Therefore, the only currency there is to be used are electrons. Plus indicates that the element has become more positive and this can only happen if it has lost an electron. Therefore, if in normal state the number would be equal to the proton which is 28 and in this state we concluded that it has lost 2- this means that it has now 26 electrons. Answer: p:28 n:32 e:26 Determine the ATOMIC Weight based on the abundance in nature Element Q has isotopes A, B, and C Isotope A has atomic mass of 40 amu, 60% in nature Isotope B has a.m. of 44 amu, 25% in nature Isotope C has a.m. of 41 amu, 15%  in nature Determine the supposed atomic weight?Solution: (0.60x40amu)+(0.25x44amu)+(0.15x41amu)= 41.15 Atomic weight and avogadro's number"<ul><li>atomic weight represents  the average mass of an atom of an element in amu and it is the mass of one mole of the element in grams; 12g/mol or 12 amu.</li><li>mole is number of units/ things equal to avogadro's number</li></ul><div>Example:</div><div>Atomic weight of 12 amu means that 6.02x1023 carbon atoms  have combined mass of 12.0 grams</div>" Rutherford<ul><li>in 1910, Ernest Rutherford provided experimental evidence that there is  a dense positevly charged nucleus </li><li>acomplished by shooting alpha particles at a golden foil and noticing how all of them didn't pierce through the foil in straight way but actually change directions and some bounce back. This concluded that amongst vast space there is also a dense area of charged particles.</li></ul> Max Planck- First Quantum Theory <ul><li>Energy is emmitted as electromagnetic radiation from matter in discrete bundles called quantum</li><li>Energy of quantum can be calculated by this equation:</li><li>E=hf , where h is a Planck constant (6.62x10-34J*s), and f/ v is the frequency of radiation.</li></ul> Bohr  Model-1913, Danish Physicist used the knowledge of Rutherford and Planck to propose the electronic structure of hydrogen -With Planck's Quantum theory  he placed restrictions on the possible values of the angular momentum  of an electron orbiting a hydrogen nucleus: L= nxh/ 2(pi), where n is the principle quantum number and h is the Planck constant - this also worked for the enegry of the electron to be quantized: E= -RH/n2 where RH is a constant, Rydberg unit of energy (2.18x10-18 J/electron) """Jumping of electrons"""-Transfering the amount of energy exactly the difference between one orbit from another can cause an electron to jump or go to a higher state Excited state of an atom- when one electron is moved to a subshell of higher than normal energy Ground statelowest energy  radius defined (n=1) AHED - WHEN ELECTRON GOES FROM LOWER TO HIGHER ENERGY absorb light higher potential excited distant from nucleus atoms at room temp- are at ground state, meaning the electrons are in the lowest possible orbitals atomic emission spectra- with heat or energy, electrons can get excited and jump up to higher energy level. In this Excited state, electrons will return in their ground state level via emission of discrete amounts of energy in form of photons  - formula for calculating the eectromagnetic energy of these phtons can be determined using E=hc/λ h is a Planck constant  c is the speed of light which is 3.00x108 m/s λ is a wavelenght of radiation - this formula is just a combination of E= hf and c=fλ - when electron gets back to ground state  it will emit a photon with a wavelength caractheristic of the specific energy transition it undergoes. line spectrum-since  energy transitions are not continuum, but there are quantized (localized), specturm is composed of light at specific frequencies. -each electron possesses a unique atomic emission spectrum due to being excited to a different set of distinct energy levels. This can be used to ID the element. Lyman seriesthe group of hydrogen emission lines corresponding to transition from energy levels n≥2 to n=1 (like returning to ground state)  Balmer seriesthe group of hydrogen emission lines corresponding to transition from energy levels n≥3 to n=2 (like returning to ground state). 4 wavelengths in the visibile region. Pascheen series the group of hydrogen emission lines corresponding to transition from energy levels n≥4 to n=3 (like returning to ground state)  E=hc/λ=hfENERGY ASSOCIATED WITH CHANGE OF PRINCIPAL QUANTUM NUMBER FROM A HIGHER INITIAL VALUE TO A LOWER VALUE (E=hf)  IS EQUAL TO THE ENERGY OF THE PHOTON ( hc/λ) Combinign bohr and planck equations:  E= hc/λ=Rh[1/n2i-1/n2f] basically energy of the photton is the difference between energy difference betweeen two energy levels. Atomic Absorption Spectra exciting electrons of a particular elements results in energy absorption at specific wavelengths  because each electron to be excited to a higher state needs to absrob the exact amount of energy. - wavelengths of absorption and emission are equal 1. The valence electron in a lithium atom jumps from  energy level n=2 to n=4. What is the energy of this transition in joules? In eV? (RH=2.18*10-18J/ electron= 13.6 eV/electron).E=\(hc/λ\)= RH [ 1/ni2 - 1/nf 2 ] E= 2.18*10-18 J/ electron *[1/4-1/16] E=2.18*10-18 J/electron * 3/16 =4.0875*10^{-19}J/electron E=13.6 eV/electron* 3/16 = 2.55 eV 2. If an electron emits 3eV of energy, what is the corresponding wavelength of the emitted proton? (Note: 1 eV=1.60x10-19J, h= 6.626 x 10-34 Jxs)"E=hc/λ => λ= hc/E λ=[6.626*10^-34Js * 3.00*10^8m/s]/ 3eV *[1eV/ 1.60x10^-19]=4.14125x10-7 m λ=4.14125x10-7 m •109nm/1m=  414nm " 3.Calculate the energy of a photon of wavelength 662 nm? (h=6.626x10-34J*s)"E=hc/λ E=[6.626x10-34J*s x 3.00*108 m/s]/662nm*[109nm/1m]=3.00*10-19J" Quantum Mechanical Model of Atoms-Bohr model was good but it wasn't adequate to explain a structure and behavior of atoms containing more than one electron - Difference between quantum mechanics and Bohr's model ide is that electrons  do not follow circular pathway at a fixed distance from nucleus -Now we know that electrons move rapidly and are localized within regions of space around the nucleus called orbitals Orbitals-regions within electrons are localized around the nucleus Current Quantum Mechanical Model fails to...-pinpoint exactly  where electron is at any given moment.  Heisenberg Uncertainty Principle- it is impossible to simultaneously determine with perfect accuracy, ther momentum and the momentum and the position of an electron. If we want to assess the position of electron we have to make the electron stop and remove its momentum, but  if we want to assess its momentum the electro needs to be moving. Quantum numbers-n,l,ml,ms Modern atomic theory postulates-any electron in an atom can be completly described by 4 quantum numbers Pauli Exclusion Principle-no 2 electrons in a given atom can possess the same set of quantum numbers. Energy State-The position and energy  of an electron described by its quantum numbers Quantum number connectivness (address)value of n limits value of l and value of l limits the value of ml Principal Quantum Number (n)-any positive integer value - higher the number higher the energy level and the radius of electron's shell Maximum number of electrons within a shell"within each shell there is a capacity to hold a certain number of electrons #= 2n2 , where n is the principal quantum number " The difference in energy between two shells decreases as the distance from the nucleus increases Bc energy difference  is a function  of [1/ni 2 - 1/nf 2 ] 1/4-1/16=3/16 -> smaller (2 to 4) 1/1-1/4= 3/4 -> bigger  (1 to 2) n describes...energy of an electron Azimuthal Quantum Number \(l\)- describes angular momentum -refers to shape and numbers of subshells within a given enegry level (shell) shells-paths that electrons follow around the nucleus subshellsfields throught which those electrons move \(l \) is important..-for bonding and bond angles (angular) - limited by value of n (\(l\)= n-1) - n values tell you the values of possible subshells \(l\) Spectroscopic notation- Refers to the shorthand representation of the principal and azimuthal quantum numbers -In this system n stays a number but numbers of \(l \) subshell are assigned a letter l=0 is subshell called s l=1 is subshell called p l=2 is a subshell called d l=3 is a subshell called f Exercise: Electron in the shell n=4 and l =24d subshell Within each subshell..."-there is a capacity to hold a certain number of electrons given by:  maximum # of electrons within a subshell= 4\(l\)+2 - the energies of subshells from different  principal energy levels may overlap. For instance 4s will have lower energy than 3d subshell" Magnetic Quantum Number m\(l\)-specifies the particular orbital within a subshell where an electron is most likely to be found at a given  moment in time. Each orbital can..."- hold maxiumum of 2 electrons  - possible values of ml are  integers between  -l and +l including 0 - if l=0, there is only one possible value for ml which is 0, there is only one orbital in s subshell - the p subshell  with l=1, has 3 values of ml (-1,0,1). Ergo, there are 3 orbitals in p shell -d subshell has 5 orbitals ml (-2,-1,0,1,2) - f subshell has 7 orbitals ml (-3,-2,-1,0,1,2,3) " the shape of the orbitals like the numbers of orbitals is......dependent on the subshell they are found Example s orbital are always spherical, while p orbitals are each dumbbell-shaped and align along the x,y, and z axes Formula for calculating orbitalsm\(l\)= 2l+1 or for n it is n=n2 For any value of n there will be max of....2n2 electrons PSE and orbital blocks"p block contains six groups of element (13-18) s block cintains two elements in each row  of the periodic table  d block contains 10 elements f block contains 14 elements (look at a picture) <img src=""IMG_71BCBC8D103F-1.jpeg"">" In classical mechanics... an object spinning about its axis has  an infinite number of possible values for its angular momentum.  Electron...has 2 orientations designated +1/2 and -1/2  and defies the rule of classical mechanics. whenever two electrons are in the same orbital, they...must have opposite spins (⥮) - reffered as being paired electrons with same ms values are said to... "-have parallel spins. <img src=""IMG_500C97D7FB97-1.jpeg""> " Electron ConfigurationsFor a given atom or ion, the pattern by which subshells are filled, as well as number of electrons within each principal energy level  and subshell are designated by its electron configuration. Electron configurations use......Spectroscopic notation *First number denotes the principal energy level, the letter designates tbe subshell, and the superscript gives the number of electrons in that subshell.* 2p44 electron in the second (p) subshell of second energy level. Energy levels below 2p have been filed 1s2 2s22p4  Aufabu principlesElectrons fill from lower to higher energy subshells  and each subshell will fill completly before electrons begin to enter the next one. n + \(l\) rule-lower the sum of values of the first and the second quantum number, n and l the lower the energy and a subshell. - meaning lower  the sum will have a lower energy and fill with electron faster. Exercise: Which will fill first, the 5d or the 6s subshell?if we use the rule n+l we can see that 5d subshell has n=5 and d=> l=2. On the other hand, 6s has n=6 and s=> l=0. Therefore If we add up the numbers of each ,the one with the lowest energy will fill up faster.Ergo, 6s is the solution. Electron configurations can be abbreviated...starting with pottasium...[Ar]. What is the electron configuration of Z=76?[Xe]6s24f145d6  for this type of proble you need to know the subshells in the periodic table. first you need to do is take a noble gas of the row prior and then start from the first group until you reach your element counting down the orbitals. PRACTICE For determining the electron configuration of anion/cation...-you just write it as a neutral number and depending on a sign take away or add electrons. - if multiple subshells are tied for the highest n value, then electrons are removed from subshell with highest \(l\) value amon these. Example. What is the electron configuration of Fe3+"- [Ar]4s2 3d6 this is for normal Fe -[Ar]3d5 this is for Fe+3 (highest l value goes out first)" Hund's Rule - orbitals are filled in such that there are a maximum number of half-filled orbitals with parallel spins Example. According to Hund's rule, what are the orbital diagrams for nitrogen and iron?"[N]  => 1s22s22p3      ⥮ ⥑ ⥑ ⥑ ⥮ [Fe] => [Ar] 4s2 3d6     ⥮ ⥏ ⥏ ⥏ ⥏ ⥮ " Important corollary of Hund's rule...-is that half-filled and fully filled orbitals have lower energies than other states. 2 exceptions: Chromium and Copper  Cr: [Ar] 4s2 3d4 -> this would be the order according to the pse. However if we take into the account that Cr would be more stable if electron from 4s subshell would go to 3d subshell.  Cr: [Ar] 4s1 3d5 Cu: [Ar] 4s1 3d10  instead of  [Ar] 4s2 3d9 Presence of paired and unpaired electrons......affect chemical and magnetic properties of an atom or molecule. Paramagnetic materials are...- materials composed of atoms with unpaired electrons will orient their spins in alignment with a magentic field  and the material will be weakly  attracted  to the magnetic field Diamagnetic-Materials consisting of atoms that have only paired electrons will be slightly repelled by a magnetic field. Valence electrons"- ""active electrons"" in the outermost shell that participate in bonding  s subshell are valence electrons for group 1 and 2 s and p subshell electrons are valence electrons for Group 13-18 s and d subshell are valence electrons for transition metals s and f subshell  are valence electron for lanthanide and actinide series " Periodic Table-1869, Dmitri Mendeleev publsihed the first version of PTE - ordered by atomic weight Henry Moseley revised it  based on increasing atomic number  Periodic law statesthe chemical and physical properties of the elements are dependent, in a periodic way, upon their atomic numbers PTE arrangments- period (rows) - groups (columns) Periods-7 -represent the principal quantum number (1-7) Groups-contain elements with same configuration Roman numerals- represents number of valence electrons elements in that group - combined with A and B letters to seperate elements into two larger classes. IA-VIIIA or...- representative elements  - have their valence electrons in the orbitals of either s or p subshells. B elements or...- nonrepresentative elements - include both the transition elements which have electrons s and d subshells and the lanthanide and actinide series which have electrons in the s and f subshells For Group A  (representative) elements...-roman numeral and letter determine the electron configuration Types of elements....metals, nonmetals, metaloids (semimetals) Metals"-left side of the PSE - active metals, transition metals and the lanthanide and actinide series of elements. -Lustrous (shiny) solids, except mercury which is a liquid - high melting points and densities with exception of lithium - ability to be deformes (malleability) - ability to be pulled into wires: ductility  " On atomic level, metals are defined by...-low effective nuclear charge - low electronegativity (high electropositivity) -large atomic radius and small ionic radius Many of transition metals (Group B) -have two or more ocidation states - electron on these metals are loosely tied to the nucleus and they are free to move which makes them good conductors Valence electrons of metals-active metals- s subshell -transition metals- s and d subshells - Lanthanide and actinide- s and f subshells Non reactive transition metals such as nickel, copper, gold and silver,  palladium, platinum - good jewlery material. Nonmetals- upper right side of PSE -brittle (fragile; easy to break) as solids with no luster. Ergo, nonmetals. - high ionization energy, electron affinities  and electronegativities.  -small atomic radii and large ionic radii -All these properties makes them hard to let go off their electrons. - less unified than metals Metalloids (semimetals)-stair-step group of elements - semi because they share mix of both nonmetal and metal properties -Electronegativity and ionization energy lies between non metal and metals - density, melting, boiling vary widely and can be combination bof metallic and nonmetallic properties. Si (silicon)- luster, but it's brittle and poor conductor Metalloids are dependent  on the elements with which they are reactingBoron (B) behaves like a nonmetal when reacting with sodium and like metals when reacting with fluorine. Metalloids- boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po), and astatine (At).  Periodic Properties of Elements- 3 rules"1st- as one moves left to right across a period, electrons and protons are added one at a time As the positivity of nucleus increases the electron surrounding the nucleus experience a stronger electrostatic pull yoward the center of the atom. This causes the electron cloud. The outer boundary defined by the valence electrons to move closer and bind tightly to the nucleus. This ""attraction"" is known as nuclear charge Zefff , a measure of the net positive charge experienced by the outermost electrons, this is somewhat mitigated by the closer electrons. For elements in the same period Z increases from left to right 2nd- as one moves down the elements of a given group, the principal wquantum number increases by one each time. Meaning valence electrons are increasingly seperated by subshells. This leads to reduction in the electrostatic attraction between the valence electron and the nucleus . Electrons held less rtightley as the principle quantum number increases. As one goes down the group increasing positivity f the nucelus  is mitigated by increasing shielding of the innershells so Zeff stays the same among elements within a group. 3rd- elements can also gain and/or lose electrons in orrder to achieve a stable octet." Atomic radius- half the distance between two centers of an atom of an element that are briefly in contact with eachother. - cannot be measured by a single atom - From left to right, as outer electron increase and protons inside the nucleus as well, while the number of inner electrons remain constant, positvely charged nucleus pulls outer electrons more closely therefore shrinking down the aotimc radius  ATOMIC RADIUS DECREASES FROM LEFT TO RIGHT.  AND INCREASES FROM RIGHT TO LEFT AND  DOWN A GROUP bc increasing principal quantum number implies that the valence electrons will be found farhter away from the nucelus because the number of inner shell is increasing. Largest atom will be on the lower left corner of PSE. while the opposite (upper right will be smalles (Cesium vs Helium).  Ionic radiusto understand it take two generalizations: 1. metals lose electrons and become positive, while nonmetals  gain electrons and become negative 2. metalloids can go either way  but follow the trend based on which side of the metalloid line they fall on, For instance Si behaves more like a nonmetal while Germanium acts more like a metal  - nonmetals close to the  mettaloid line require more electrons than other nonmetals to achieve the electronic configuration nonmetal close to mettaloid line have larger ionic radius - metals (IA to 7) have more electrons to lose to achieve electronic configuration  -metals close to mettaloid group have smaller radius bc they strive to reach electorn configuration Ionizatin Energy or ionization potential-energy required to remove an electron from a gaseous species  -requires heat (endothermic process) - greater the atom's Zeff the greatly the valence electrons are closer to the nucelus and more tight they are, this increases ionization energy\ - ionization energy increases from left to right  and from botom to top - to remove 2nd and 3rd electron it requires increasing amount of energy because they are removed from a cationic species First Ionization energy-Energy needed to remove the first electron Second Ionization Energy- energy to remove the second electron from a univalent cation to form a divalent  and so on.... Mg(g) --> Mg+(g) + e-  , first ionization energy; neutral to univalent Mg+(g) --> Mg2+(g) + e- , second ionization energy; univalent to divalent Elements from IA and IIA groups have low ionization energy- called axtive metals - do not exist naturally in their neutral form; they exist in ionic compounds, minerals. - loss of one electron from IA or two from IIA results in the formation of stable filled valence shell. Values for second and thir IE are larger from...The First Ionization Energy IE for Group I is larger thant IE for group 2 because...- by removing electron from the first group, they enter in noble gases state and recieve stable electronic configuration. Noble gases are liest likely to....- give up electrons Halogens- most greddy when it comes to electrons Halogens by.... -recieving an electron can go into their stable configuration -this is exothermic process which expels energy in form of heat Electron Affinity is...*Energy that vanishes by gaseous species when it gains an electron. * this is opposite concept of Ionization energy -𝚫Hrxn  because it is an exothermic process. However, the electron affinity is reported as a positive number because it refers to energy dissipitated whic his 200kJ/ mol for instance and  𝚫Hrxn is -200 kJ/mol - Stronger the pull the nucleus has on valence electrons (Zeff ↑), the greater the energy release will be when the atom gains electron. - Electron Affinity increases from right to left to right. Because the valence shell is farther away from the nucleus as the nucleus number increases, the electron affinity decreases from top to bottom. - Group 1 and 2 have lowest electron affinty while the group 17 have a very high electron affinity. - Group 18 has order of zero electron affinity bc they already have a stable octet rule. Electronegativity - measure of attractive force that an atom will exert on an electron in a chemical bond.  - greater the electronegativity of  the more it attracts electrons -  values relate to ionization energy \ - the first three noble gases do not have high electronegativity because they don't form bonds often. - measure of electronegativity values is determined by Pauling scale.(0.7 (Cesium to 4.0 Fluorine). Trends..."<img src=""IMG_8D485952DA0C-1.jpeg"">" Alkali Metals IA-Group 1 - lower densities than other metals -only one loosely bound electron in their outermost shell - Zefff are very low giving them largest atomic radii; low ionization energy, low electron affinity and low electrongeativity - easily lose one electron to form univalent cation -react readily with nonmetals Alkaline Earth Metals (IIA) - group 2 - have slightly higher effective nuclear charge  -two electrons in a valence shell, which can easily be removed to form  divalent cations -alkali and alkaline metals are called active metals because they are so reactive they are not naturally found int their neutral state. Chalcogens (VIA)- group 16  - group of nonmetals and metaloids - not reactive as halogens , they are crucial  for norma biological functions. - 6 electrons in their valence shell - small atomic radii and large ionic radii -oxygen - sulfur - selenium (protection of oxidative stress)  - remainder is metallic and toxic to organisms Halogens (VIIA)- highly reactive nonmetals with seven valence electrons -desperate to complete the octets by gaining an electron - gaseous (F2 , Cl2 ) or liquid (Br2 ) to solid (I2 ) - due to their highh electronegativity and electron affinities, they are especially reactive toward alkali and alkaline earth metals. - Fluorine has the highest electronegativity - reactive so naturally found only as ions (halides) or diatomic molecules Noble Gases (VIIIA)- inert gases with minimal reactivity - high ionization energy with little to no tendency to gain or lose an electron - low boiling points and exist as gasses at room temp - commercially used as lighting source Transition Metals (B)- GROUPS 3 TO 12 - low affinities, ionization energies and low electronegativity  - quite malleable and are good conductors due to loosely held electrons that progressively fill the d-orbitals in their valence shells. - high boiling points and high melting points - they can have different possible  charged forms or oxidation  states  bc they can loose different numbers of electrons from s and d orbitals - can form many ionic compounds - vibrant colored solutions TRANSITION METAL COMPLEX IONS...-associate in solutions either with molecule of water (hydration complexes) or with nonmetals - this contributes to the variability of the silubility of certain transition metal-containing  groupa -formation of complexes splits d-orbital into two energy sublevels which enables many complexes to absorb certain frequencies of light - nonabsorbed frequencies give the color Chemical bondsStrong attractive forces which keep atoms within a molecule together. The octet rule-atoms tends to bond with other atoms so that it has eight electrons in its outermost shell. thereby forming a stable electron configguration Noble gas argon - exceptions Hydrogen, lithium and beryllium, boron, period 3 elements and greater Exceptions to the Octet rule"Incomplete octet:  ELEMENTS STABLE WITH FEWER THAN 8 ELECTRONS IN THEIR VALENCE SHELL AND THAT INCLUDES HYDROGEN, HELIUM(2), LITHIUM(2), BERYLLIUMM(4)) AND BORON (6) -EXPANDED OCTET: ANY ELEMENT IN PERIOD 3 OR GREATER WHICH CAN HOLD MORE THAN 8 ELECTRONS, INCLUDING P, 10 Sulfur,12 Chlorine 14 and many others -odd number electrons: any molecule with odd number of valence electrons cannot distribute those electrons to give eight to each atom. For instance NO has 11 valence electrons" Ionic Bonding- electron or electronss gets transferred from an atom with low ionization enegry (metal) to an atom with high electron affinity (nonmetal).  -  electrostatic forces between opposite charges is what hold the ions together - electrostatic force can form a lattice Covalent Bonding"-an electron pair is shared between two atoms (nonmetals) if it's unequally shared = polar if it's equally= nonpolar if both electrons are contributed only from 1/2 atoms= coordinate covalent - covalent bonding consists of individually bonded molecules" Ionic bonds- between two atoms of significantly differet electronegativites - cation and ion - for this to occur electronegativity must ne greater than 1.7 on the Pauling Scale - because of the strenght of electrostatic force between ions: they have very high melting and boiling points - dissolve in polar solvents, in the motlen or aqueous states - good conductors of electricity Covalent bond- when two or more atoms with simmilar electrongeativities interact the energy to transfer an electron is greater from the energy released once the ionic bond is formed. it is energetically unfavorable -They rather share electrons -It the attraction each electron in the shared pair has for 2 positive nuclei - poor conductors and reletivley weak intermolecular interaction Properties of covalent bonds- atoms can share more pairs of electrons (1,2,3 bond) -Bond length- average distance between teh two nuclei of atoms in a bond. As the number ofelectron pairs increase atoms are pulled more closely together. -Bond energy- more energy is required to break the bond the more electron pairs are invovled -Polarity- when two atoms have a relative differnce in electronegtivities which creates a dipole 7 common diatomic elementsH2,N2,O2, F2, Cl2, Br2, I2 Non polar bonds- less than 0.5 is generally considered nonpolar Polar Covalent Bond - difference in electronegativity from 0.5 to 1.7 - causes seperation of charge across the bond - this results i more electronegative element  acquiring a greater portion of the electron density, taking on a partial negative charge and the other elements a smaller portion of the electron density.  H⇸ Cl for instance polar molecule or dipole moment of a ppolar bond is a vector wuantitiy  given by equation...... p=qd -where g is the charge, p is the dipole moment and the sd is the displacment  vector seperating 2 partial charges. - measured in Debye units (C/m) Coordinate Covalent Bonds-   both of shared electrons originated from the same atom.  - lone pair of one atom attacked another atom with unhybridized p-orbital to form a bond.  - they are indistinguishable  from any other bonds Lewis acid- any compound that  accepts a lone  pair  Lewis base- any compound that will donate a pair of electron to form a bond Lone pair electrons- unshared electrons in the valence shell Covalent Bond notation- Lewis Structure - most stble the one that minimizes the number and magnitude of formal charges Rules for drawing Lewis Dot Structures1. draw the backbone structure of the compound (uusually the least electronegative) 2. Count all valence electrons 3. draw single bonds between the central atom and the atoms surrounding  it 4. complete octet rules of all atoms bonded to central atom then add last extra electrons to the atom Formal Charge"FC= V-Nnonbonding-1/2Nbonding V= normal number of electron in the atoms valence shell Nnonbonding= number of lone electrons Nbondingnumber of electrons in a bond formal charge= valence electrons minus dots minus sticks" Formal charge vs oxidation number- formal charge underestimates the effect of the electronegativity differences - oxidation number overestimates the effect of electronegativity differences, assuming more electronegative electron has 100% share of electron Resonancesame arrangment of atoms but different placments of electrons and bonds  Exceptions to the Octet RulesH,Be,He,Li,Ber, B - ATOMS BEYOND 3RD PERIOD Valence Shell Electron Pair Repulsion Theory- uses lewis structures to predict the molecular  geometry of covalently bonded molecules - 3d arrangments of an atoms surrounding the central atom is determined by the reupulsions between bonding and nonbonding  electron pairs in the valence shell of the central atoms - the whole idea is to minimize  the forces by moving away as far as possible COMMON GEOMETRIC ARRANGMENTS1. LINEAR 2.TRIGONAL PLANAR 3. TETRAHEDRAL 4.TRIGONAL BIPYRAMIDAL 6. OCTAHEDRAL EXCEPTION (NH3) TRIGONAL PYRAMIDAL AND CO2 LINEAR Electronic geometry and molecular geometry- eletctronic geometry describes the arrangment of both bonding and nonbonding electrons - molecular gemotery examines only the arrangment of bonding pairs of electrons (number of atoms that surround central atom or coordination number is a relevant factor) Ideal bond angle- 109.5 degrees - tetrahedral associated Polarity of molecules - atoms of different electronegativity -based on spatial orientation it can be polar or nonpolar (if it cancels out) - when it doesn't cancel out there will be a net dipole moment Atomic and Molecular Orbitalspi bond and sigma bonds  pi bond when electrons clouds are parralel and sigma bond when oribtals overlap head to head - sigma bond in single bond - sigma and pi bond in double and tripple bond Intermolecular Forces- London dispersion forces-the bonding electrons in nonpolar covalent bonds may nt be shared equally between atoms because at any point of time they will be located randomly through the orbital -Ergo, electron density may be unequally distributed between 2 atoms - This creates a rapid polaziration and counterpolarization  of the electron cloud and the formation of short dipole moment. - these dipoles interact with the electron clouds of neighbouring compounds inducing the formation of more dipoles. (temporarily negative end of molecule will cause neighbouring region to be positive) London Dispersion Forces-attractive/ repulsive interactions of these short-lived and rapidly shifting dipoles are known as London Disperison Forces. - weakest of all interctoons - depends how easy it is to polarize a molecule. Large molecules are more easily polarizable than smaller . - important for noble gases  which allows them noble gasses to liquify Dipole-Dipole interactions- temporarily bonding interaction - energetically favorable due to attractive electrostatic force - negligible in gas phases - due to these polar molecules have higher boiling and melting points  Hydrogen bonding-FON- elements with hydrogen attach which can form these types of bonds - form of dipole-dipole interaction - intra- or inter-  molecular - no sharing of electron - hydrogen has a role of naked proton bc it has a small amount of electron density in covalent bond - unusually high boiling points - particular to h20, oh, amines and COOH Molecules and Moles- molecule- a combination of 2 or more atoms held together by a covalent bonds. - smallest units of compounds that display their identifying properties - molecules can be composed of same elelment or of different elements - we measure the amounts of these compounds in terms of moles or grams, using molar mass to interconvert between units  Ionic compounds do not...- form true molecules because of the way in which oppositely charged ions arrange themselves in the solid state - 3d arrays of charged prticles that comprise the compound - NaCl is just na surrounded by cl in solid state - since the molecule doesn't exist, molecular weight becomes meaningless so the term formula weight is used instead Molecular Weight - atomic weight is a mismoner because it is actually weighted average of the massess of the naturally occuring isotopes of an element not their weights - sum of atomic weights of all atoms ina a molecule and the units are amu (atomic masss units)/ molecule Mole- quantity of any substance equal to the number of particles that are found in 12 grams of carbon-12 isotope. - defined as avogadrov's number 6.022x 10^23 mol^-1 -1 mole in a compound has a mass in grams equal to the molecular or formula wieght of a compound in amu.  - molecular weight mass per molecule - molar mass mass/ mole of molecule n=m/M WHERE N IS THE NUMBER OF MOLES OF A SAMPLE SUBSTANCE Equivalent weight - some elemnts or compounds can act more potently than others in performing certain reactions. -one mole of hcl will donate one mole of hydrogen ions a certain mass of HCl (36.5) will donate one equivalent of hydrogen ions - amount of compound measured in  grams that produces one equivalent of the particle of interest is called the gram equivalent weight:  gram equivalent weight= molar mass/n  n is number of particle of interest produced equivalent weight- a compound is the mass that provides one mole of the particle of interest Equivalents- when we know the amount of compound in a reaction we can determine how many equivalents arep resent equivalents= mass of comound/ gramequivalentweight Measurement of normalityN- measure of concentration (equivalents/L) - most commonly used for hydrogen ion concentration - molarity= normality/ n Chemical Kineticschemical kinetics is the study of reaction rates, the effects of reaction conditions on these rates and the mechanisms implied by such observations. Reactions can be...-spontaneous and nonspontaneous -change Gibbs free energy determines whether or not a reaction will occur. - even if it is a spontaneous reaction it doesn't mean  it will run quickly. - enzyme selectively enhance the rate if certain reactions by factor of 10^2 - 10^12 Reaction Intermediates aredifficult to detect because they may be consumed almost immediately after they are formed but a prposed mechanism that includes intermediates  can be supported through kinetic experiments. Rate-determining step- slowest step in any proposed mechanism  - rate of whole reaction is only as fast as the rate-determining step. Collision Theory of Chemical Kinetics"- for rxn to occur molecules must collide with each other - ""rate of a reaction is proportional  to the number of collisions/ second between the reacting molecules""" Effective collision-occurs only if the molecules collide with each other in the correct  orientation ad with sufficient energy to break their existing  bonds and form new ones. "Activation energy (Ea )/ energy barrier"- minimum energy for a rxn to take place - only a fraction of collision  have enough ikinetic energy to exceed the activation energy Rate of rxn can be expressed:  rate= Z x f Z= total number of collisions/ s f= fraction of collisions that are effective More elaborate quantative anaysis can be expressed with Arrhenius equation: k= Ae-Ea/RT   k is the rate constant of reaction  A is the frequency factor (measure of how often molecules in a certain rxn collide) (s^-1) Ea is the activation energy of the reaction R is the ideal gas constant T is the temperature in Kelvin  "Transition State Theory"-when 2 molecules collide with energy ≥ activation energu, they form a transition states where old bonds are weakend and the new bonds begin to form. - transition states dissociate into producst fully forming new bonds - also called activated complex has the greater energy than both reactants and the products and it is denoted by the symbol cross-like - energy required to reach the transition state is the activation energy - it can form products or revert back to reactants without any energy input "Transition states vs  reaction intermediates"- transition states are theoretical constructs (can't be isolated) that exist ast the point of maxiumum energy, rather than distinct identities  with finite lifetimes "Free energy diagram ilustrates the relationship between..."1. activation energy 2.the free energy of the reaction  3. the free energy of the system "The free energy change of a reaction is..."the difference between the free energy of the products  and the free energy of the reactants. "negative free energy  change indicates...."exergonic reaction (energy is given off) "positive free energy change indicates...."endergonic reaction  (energy is absorbed)  "the transition state exists...""at the peak of the energy  diagram  -difference between the transition state and the reactants  is the activation energy  of the foward rxn - difference between the transition state and the product is the activation energy of the reverse reaction <img src=""IMG_13E5DC09D037-1.jpeg"" style=""float: right;"">" "Factors affecting Reaction Rates 1"1. Rxn concentrations  greater concentration of rextants greater the number of collision/ time (Increase in frequency factor A in Arrhenius equation. Rxn will increase for all but zero-order rxns - in gaseous state partial pressure of the gas is used as concentration "Factors affecting Reaction Rates 2"2. Temperature - when temp increses tyhe reaction rate will too. - temp is measure of particle's average kinetic energy of the molecules - nuclear reactions temperature dependent "Factors affecting Reaction Rates 3"3.Medium - aqueous solutions or non aqueous (DMSO), gases etc - Polar solvents preffered because their molecular dipole tends to polarize the bonds of the reactants. thereby, legnthening them and weakening premitting reactions to occur faster "Factors affecting Reaction Rates 4""4. Catalysts -substances that icnrease reaction rate - react either through adsorption or formation of intermediates - they can increase # of collision; change relative orientation (making collisions more effective, donate electron density to reactant molecules. - in the homogeneous catalysis, the catalyst is in the same face as reactants - in heterogenous catalysis; the catalyst is in distinct phase - catalyst has no impact on free energy of reactants and products only on activation one - have no  impact on   the equilibrium position or measurment of Keq " we can describe the rate of generic reaction 2A + B -> C in terms of..either the dissaperance of the reactants over time or dissaperance of products over time. because the reactants are being consumed in the process of forming products we...place a negative sign in front of the rate expression for the reactants For 2A + B --> CA= - 𝚫[A]/𝚫t B=- 𝚫[B]/𝚫t C= +𝚫[C]/𝚫t - rates of change for concentration are not equal  bc of stochiometric coefficients  to show this we use this: aA+bB->cC +dD where rate is: rate=- 𝚫[A]/a𝚫t= - 𝚫[B]/b𝚫t=+𝚫[C]/c𝚫t=+𝚫[D]/d𝚫t Rate unit is...mol/L*s or M/s Determination of Rate Law for all forward, irreversible reactions the rate is...*proprotional to the concentrations of the reactants, with each concentration raised to some experimentally determined exponent. *For instance, aA+bB->cC +dD the rate is proportional to [A]x [B]y  if we include proportionality constant we get: rate= k[A]x [B]y  k- rate constant, rxn rate coefficient x,y- orders of reactiond This is rate law units: conc/ time (mol/s) Reaction rate is theoreticallymeasured at any time but it is done at the beginning to minimize the effect of reverse rxn. Experimental Determination of Rate Law PRACTICE: Consider a reaction with A and B forming a C. imagine 2 trials where A is constant but  B doubles. If C quadrupled what is the exponent of B?rate= k [A]x [B]y  2y =4, y is equal to 2 "Find rate law <img src=""IMG_37CB495B9479-1.jpeg"">"To solve this first look at the reactants. There is only 2 so the rate law eq should look like this:  rate= k  [A]^x [B]^y we take the first and the second trial. We can see that if we double B the rate quadruples. Ergo, we know that conc of B can affect the rate. So we can calculate the exponent based on that while keepoing A negligible bc it remains constant, so we assume that it does not affect the rate. [B]^y=4 since it quadrupled 2^y=4 since B doubled and we can write this as 2^y= 2^2 and we can get that y=2 For exponent of A we use second and third trial bc conc of A changes while B remains const.  When we double A the rate doubles so:  2^x=2 x is equal to 1 And we can propose a rate law: rate= k [A][B]^2 and if we are asked to calculate k just use the data of one trial from the table. For instance 1st trial: 2.0M/s=k (1.00M)X(1.00M)^2 k= 2.00 M^-2s^-1 Reaction OrderZero order, first order, second order, higher order, or mixed order Zero-Order Rxn"- rxn in which the rate of formation of productt C is independent of changes in concentration - rate=k bc [A]^0[B]^0 - rate constant is dependent on temperature so we can change it with change of temp.Other way is  by adding a catalyst which will increase it value - if we try to plot zero-order reaction on concentration vs. time curve results in a linear graph.  -<img src=""IMG_9BAE68BD749E-1.jpeg""> " First- Order Reaction"- has a rate that is directly proportional  to only one reactant, such that doubling concentration of that reactant results in a doubling of the rate of formation of the product. rate= k [A]^1 or rate= k[B]^1 k has units of s^-1 - radioactive decay is an example: r= -𝚫[A]/𝚫t = k [A] concentration can be expressed at anytime t [A]t =[A]0e-kt Ao initial conc k is constant t is timw - first order rxn suggest begins when the molecule goes under chemical change by itself without chemical interaction and without physical interaction conc vs. time graphs curved graph ln[A] vs time gives a straight graph and it's slope is the opposite of the rate of constant, k  <img src=""IMG_9CC04B2471A8-1.jpeg""> " Second- Order Reaction"- proportional to the concentrations of two reactants or to the square of the concentrations of a single reactant - rate= [A][B] or k[A]^2 or k[B]^2 - k has units of M^-1s^-1 second-rate law often suggest a physical collision between two reactant molecules - plotting single reactant vs, time  1/[a] vs. time reveals a linear curve; slope of such curve is equal to linear constant <img src=""IMG_3A8B48D3B30B-1.jpeg""> " Higher- Order Reactions are....- rxns with varying orders during a reaction usually a fraction -rare for three particles to collide simultaneously with correct orientation and sufficient energy. Reversable reactions - rxn that an proceed 2 ways forward and reverse - if it is isolated rate of product and reactant formation will become same and reactanst and product conc will become constant - in dynamic equilibrium thw forward and reverse rxn still occuring' they don't stop it occurs when forward and reverse rates are equal A⇋B- at equilibrium conc of A and B will remain constant (NOT EQUAL) -rxns A to B and B to A still occu at equal rates - rxn reaches equilibrium when entropy (energy distribution) is max and the Gibs free energy system is min Law of Mass Action aA + bB ⇋ cC + dD Ig  the system is at equilibrium at a constant temp, then the following ratio is constant: Keq= [C]^c [D]^d / [A]â [B]^b  Law of Mass action is...related to the expressions for the rates of foward and reverse rxns. 2A ⇋ C +B ratef = kf [A]^2 rater =kr [B] [C] r=r THIS MEAN RXN IS AT EQUILIBRIUM rf /rr = [B] [C]/ [A]^2 OR Kc Kc is....-equilibrium constant, where c is concentration - when talking about gasses it is Kp When a rxn occurs in more than one step then...-we multiply the k of each step together and write down the product and reactants For example: k1k2/k-1k-2 k pos is forward k negative is reversed Kc= k1k2k3/k-1k-2k-3 = [C]^c[D]^d/ [A]â[B]^b what is the expression for the equilibrium constant for the following rxn: 3H2(g) + N2(g) ⇋ 2NH3(g)Kc= Keq= NH3^2/ h2^3N2 Reaction Quotient- equilibrium is a state that is achieved only through time  - reaction quotien Q serves as a timer - formula for Q is the same as Keq but  - when calculating value q concentrations are not constant - value not important but comparison between Q at any given time and the knwon Keq of equilibrium Q<Keq means- forward rxn has not reached equilibrium - more reactants - foward rate is increased to restore equilibrium Q=Keq- rxn in dynamic equilibrium - ractants and products are present in equilibrium proportions - forward and reverse are equal  Q>Keq- forward rxn exceeded the equlibrium - grwater conc of products - reverse rate of rxn is insreased to restore equilibrium Properties of the Law of mass Action- concentration of pure solids and pure iquids do not appear in the equilibrium constant expression bc this is based on the activity of compounds not concentrations - equolibrium constant is temperature dependent larger the value of Keq the fRTHER TO THW RIGHT THE EQUILIBRIUM POSITION - EQUILIBRIUM CONSTANT FOR REVERSE REACTION IS 1/Keq Equilibrium calculations-large positive the exponent of keq indicates rxn that almost goes all way - large negative means rxn favor reactants whe Keq has a large negative exponent...it makes it  easy to calculate the concentration Example: A⇋B + C , where Keq=10^-12 Keq= [C][B]/[A] IF X AMOUNT OF A REACTED AND X AMOUNT OF C AND B IS PRODUCED: - assume A conc is 1 Keq= 10^-12= (x)(x)/(1-x) since Keq is so large we can make it negligible so 10^-12= x^2/1 x=10^-6 calculations with the equilibrium"<a href=""file:///Users/danilorocenovic/Downloads/IMG_5737.HEIC"">file:///Users/danilorocenovic/Downloads/IMG_5737.HEIC</a><a href=""file:///Users/danilorocenovic/Downloads/IMG_5738.HEIC"">file:///Users/danilorocenovic/Downloads/IMG_5738.HEIC</a>" 6.2 Le Chatelier's principle- if the stress is applied to the system, system will act in such a way to relieve the stress Changes in conc in equilibriummore reactant will shift rxn to the right more product wil shift equilibrium to the left if we remove some conc from product it will shift right if we remove some conc from reactants  it will shift left Changes is pressure/ volumestronger the pressure smaller the volume and vice versa  - if the pressure is strong it willl act in such a way that it will go towards the side where's less moles of gas Changes in Temperature- q is the same  - keq has a diff value -determined by enthalpy delta H +Delta h ; heat reacts as reactant  - delta h; heat functions as product Kinetic and Thermodynamic Control-reactants can undetgo  two different sets of rxns - at lower temps those are kinetic products -at higher temp  those are thermodynamic products - kinetic rxns involved require less  free energy, while thrmodinamical require more ( kinetic products are fast products) - however, thermodinamicall profudtcs have lower free energy which makes them more stable than kinetics - these are example of regulations in rxns System and Processes- system is the matter that is being observed- total amounts of reactants and products in a chemichal reaction -environment or surroinding is everything else outside of that system Systems are characterized by...whether or not they can exchange hear or matter with the surrounding. We have: 1. Isolated: system does not exchnage energy (heat or work) or matter with the surroundings 2.Closed: system can exchange heat or work (energy) but not matter with the surrounding 3. Open: The system can exchange both energy (heat and work) and matter with the surroundings Under process we say...that a system experiences a change in one or more of its properties (f.i. conc of ractants or products, temp, or pressure) Many of the processes create special conditions bc...they allow us to simplify the first law of termodynamics. 𝚫U= Q-W where: 𝚫U is the change in internal energy of the system Q is the heat added to the system W is the work done by the system 4 types of processes...Isothermal Adiabatic Isobaric Isovolumetric Isothermal processes occur..."- when the system's temperature is constant - bc internal energy and temp are directly proportional law simplifies to: Q=W - if we were to try to graph it it would be best described pressure vs volume based on the formula p=nRT/ V -hyperbolic curve and work is the shaded area under the curve <img src=""IMG_A555ECDD24D1-1.jpeg"">" Adiabatic processes occur..."- when no heat is exchanged between the system and the environment; therefore thermal energy system is constant. When Q=0 𝚫U=-W - represented with a hyperbolic curve  also as a p vs volume <img src=""IMG_D393DD2FFE8A-1.jpeg"">" Isobaric processes occur "-when the pressure is kept constant. - it doesn't alter the first law and the graph is a flat line on p-v graph <img src=""IMG_F366E61A2646-1.jpeg"">" Isovolumetric process occur...- when there is no change in volume. - because the gass neither shrinks or expands, the equation is simplified to: 𝚫U=Q - vertical line on p-v Processes can also be classified as...-spontaenous vs nonspontaneous  - 𝚫G,𝚫S,𝚫H can tell us if the rxn is spontaneous or nonspontaneous spontaenous can occur...-don't have to be driven with energy from an outside source  -doesn't  mean they will or either they will go to completion - some have high activation energy Enzymes have role as...-catalysts. they enhance the rate of certain reaction (but slow) - supplying energy for non spontaneous rxn involves coupling them to spontaneous ones. state of a system can be described by...- macroscopic properties - they can not describe the process of the system just describe the system in an equilibrium state pathway taken from one equilibrium state to another is described quantitatively by...work(W) and heat(H) State Functions are.....-pressure (p) -density (ᵠ) -temperature (T) -volume (V) -enthalpy (H) - Internal energy (U) -Gibbs free energy (G) - Entropy (S) when the state of system changes from one equilibrium to another...- one of two or more of the state functions will change as well mnemonic for state functionwhen under PRESSURE and feeling DENSE. TV and HUGS can help "Due to versitality of systems  standard conditions has been defined forv measuring enthaply, entropy and Gibbs free energy."T= 25ô (298 K) P= 1 ATM c= 1 M Standard  temp and pressure... which are used for ideal gas conditions0ôC  (273 K) 1atm Under stable con ditions the most stable form of substance is called...- astandard states of that substance - H2, H20, NaCl, O2, C (graphite) - all of the variables in these elements are 0 Phase Diagram- graph which shows the standard and the nonstandard states of matter in an isolated system  - solid⇋liquid⇋gas - is reversable and an equilibrium will be rached (f.i. at 0ô and 1 atm cie will absorb heat and become a liquid and due to loss of heat  some of the liquid will solidify into ice) temperature of any substance in any phase is- related to the average kinetic energy of the molecules that make up a substance Evaporation, vaporization and condensaton- evaporation is an endothermic process for which the heat source is the liquid water -Boiling is a type of vaporization  that occurs under specific conditions -condensation facilitated by lower temp or high pressure (pressure acts as a lid) - as these two exchange the equilibrium is reaches Pressure that gas exerts over a liquid is...-vapor pressure - it increases as the temp increases Boiling point is-temperature at which the vapor pressure of the liquid equals the ambient pressure. Transition from solid  to liquid is called...- fusion or melting Transitionb of liquid to solid is called- solidification, crystallization or fusion temperatures at which these proccesses occur are...melting point or freezing points. - pure crystaline solids have distinct - glass, plastic aqnd was have range of  temperature at which they melt due to their less ordered molec structure when solid goes into a gas phase the process is called....-sublimation - deposition (reverse of sublimation) Lines on a phase diagram are called ...the lines of equilibrium or the phase boundaries and indicate the temperature and the pressure values for the equilibria between phases The lines of equilibrium  divide the diagram...into 3 regions corresponding to the three phases (solid, liquid, and gas) "<img src=""IMG_DCDBC31C615B-1.jpeg"">""Line A represents the solid-liquid interfacee Line B the liquid-gas interface Line C the solid-gas interface gas phase is found in lower temp and higher pressure the liquid moderate temp and high pressure the solid high pressure, low temp the point where three phase boundaries meet is called  the triple point  -this is the temp at which all three phases exist in equilibrium - solid and liquid phase boundary extends indefinetly from the triple point - liquid-gas boundary terminates at the critical point. it is the temp and the pressure at which two densities become  equal and there is no distinction between two phases. At and Beyond this point, t and p are zero " heat vs temperature-temperature is related to the average kinetic energy of the particles of a substance. - Hot or cold - Fahrenheit, Celsius, and Kelvin - the average kinetic  energy of the particles in a substance is related to the thermal energy (enthalpy) of the substance  - when substance thermal energy increases its temperature increases (lukewarm water may have greater total heat than a small a,ount of hot water) Heat (Q) is...- transfer of energy from one substance to another as a result of their differences in temperature. Zeroth law of themrodynamics implies...- objects are in thermal equilibrium  only when their temperatures are equal - we can calculate how much thermal energy is transferred between two or more objects as a result of their difference in temperatures by measuring the heat transferred. - heat and work are measured independently 𝚫Q>0endothermic processes in which the system absorbs heat  𝚫<Q - exothermic processes where heat is realeased unit of heatJoules or calorie for whihc 1 cal=4.184J Enthalpy and Heat are equivalent...-under constant pressure. when substances of different temp are brough into thermal contact with eachother...energy will move from the warmer to cooler substance the process of measuring transffered heat is called....calorimetry -2 types: constant-pressure calorimetry and constant-volume calorimetry The heat absorbed or released in a given process is calculated via equation:q=mc𝚫T M-MASS 𝚫T- CHANGE IN TEMP C=SPECIFIC HEAT OF SUBSTANCE Specific heat or c is...defined as the amounty of energy required to raise a temperature of one gram of a substance by one degree Celsius specific heat of water is 1 cal/gK MASS TIMES SPEVCIFIC HEAT IMPORTANT FOR COMPARING A POOL AND A BOTTLE OF WATER Constant- Pressure and Constant- Volume Calorimetry-sample isinsulated with oxygen gas and put into the water bath and ignited - bc it is isovolumetric there is no work  and bc it is isolated from rest  of the universe it is adiabatic environment  𝚫Usystem =-𝚫U surroundings qsystem= -q surrounding mc𝚫Toxygen + mc𝚫Tsteel= -mc𝚫Twater heat can  Tranfer  from system to surroundingqcold=-qhot formulasq=mcdeltat q=ml=ndeltaH for phase changes during phase change....temp remains constant qcold=-qhot- negtive bc hot gives of energy lol Heating Curve"<img src=""IMG_B818471EC563-1.jpeg"">" Enthalpy-most rxn occur under constant pressure - to express heat changes under constant pressure we use enthalpy - state function *𝚫Hrxn=𝚫H product-𝚫Hreactants positive delta H- endothermic process negatvie H- exothermis process Standard Heat of Formation- enthalpy required to produce one mole of a compound from its element in their standard states Standard heat of Rxn-𝚫Hrxn=𝚫Hproducts-𝚫Hractants Hess's Law- enthalpies are additive 𝚫H=𝚫H1+𝚫H2+𝚫H3

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