DAT General Chemistry – Flashcards
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Unlock answers| What is the shape of a p orbital? |
| figure 8 |
| If you change the amount of neutrons, what is the yield? |
| A different isotope |
| If you change the electrons, what is the yield? |
| A new ion |
| If you change the protons, what is the yield? |
| A different element |
True or False:
Molecules in the same period react the same. |
| False. Groups |
| ***On the DAT anytime you see a reactivity question with H2O, the answer is an Alkali metal |
| Question is the answer |
| Which group is the alkaline earth metals |
| group 2 |
True or False:
The noble gases are extremely reactive |
| false |
| Every shell has ____ orbitals (equation) |
| n^2 |
| What is the equation for the maximum electrons per shell |
| 2n^2 |
| In an electron configuration, what makes the configuration most stable. |
| Having the shell full or 1/2 full |
| What is paramagnetic? |
| Unpaired electrons (odd # e-) |
| What is Diamagnetic? |
| Slight deflection from magnetic field (all e-'s are paired) |
| What symbol denotes the Azimuthal subshell? |
| l |
| What type of force overpowers electrostatic repulsion? |
| Strong Nuclear Force |
| What particles are considered the heaviest? |
| Alpha particles |
| Which particle has the least penetrating power? |
| Alpha particles |
| Which nuclear particles are the lightest and have the most penetrating power? |
| Gamma Rays |
| What are the 2 checks that are needed for a nucleus to be stable? |
Even # protons and/or neutrons N/z ration = 1 |
| Which gives more energy, nuclear reactions or chemical reactions? |
| Nuclear Reactions (much more powerful) |
| Where is the e- located during electron capture? |
| The reactants |
| In electron emission, where is the electron located? |
| The products |
| In alpha-emission, where is the alpha particle located? |
| The products |
| What type of atoms are likely to undergo alpha decay? |
| z;83 large atoms |
| What is the only type of decay which loses mass number? |
| Alpha-decay |
| Why is beta decay used? |
| n/z ratio is too high |
| Why are positron emission and electron capture used? |
| n/z ratio is too low |
| What is a nucleon? |
| Anything living in the nucleus |
True or False: ; 1/2 life is constant in 1st order rxns |
| True |
| What order rxn is always seen in spontaneous nuclear decay |
| 1st order |
| What decides if something has a higher nuclear binding energy? |
| The closer it is to (56/26) Fe |
| What is the periodic trend for atomic radius/size increase? |
| Down the table, to the LEFT |
Which radius is smaller and why? ; Mg or Mg^2+ |
| Mg^2+ because cations have a smaller radius than there neutral counterpart |
Which has a smaller radius and why? ; S or S^2- |
| S because Anions have a larger radius than there neutral counterpart |
| What is the Zeff equal to? |
| The # of valence e-'s |
| What should you look for if a question asks which species will have an ionic radius that is smaller than the atomic radius? |
| LOOK FOR A METAL because metals love to form cations |
| If a question asks which species will have an ionic radius that is larger than the atomic radius, what should you look for and why? |
| A non-metal because non-metals love to form anions |
| What does an isoelectronic series mean? |
| All atoms have same # e-'s |
| What is the trend for highest 1st ionization energy? |
| Up and to the left |
| What is electron affinity? |
| Change in energy by gaining an e- |
| What is electron affinity associated with? |
| Reduction |
| Is electron affinity typically endothermic or exothermic? |
| Exothermic |
| What is the periodic trend for electron affinity? |
| Left to right. |
| What two groups are exceptions to the electron affinity trend? |
| Group containing N and group containing Be |
| How are electronegativity and polarity related? |
| The bigger the difference in electronegativity, the more polar the bond. |
True or False: ; Solid compound are good electrical conductors? |
| False |
| What do compounds with ionic bonding typically form? |
| Crystals |
True or False: ; Compounds with Ionic bonding have Very High MP but low BP |
| False: High MP and BP |
| What are the 2 types of covalent bondings? |
| Covalent networks and molecular compounds |
| What is the relative BP and MP for a covalent network? |
| High for both |
| What is the relative MP and BP for molecular compounds? |
| Low for both |
| What is the relative strength for ionic and covalent bonds? |
| Very strong |
True or False: ; Compounds with metallic bonding are electrically and thermally conductive |
| true |
| In a coordinate covalent bond, what determines a lewis acid vs. lewis base |
Lewis base- donates both electrons Lewis Acid- does not contribute electrons to the bond |
| What is the bond angle for a linear molecular geometry |
| 180 degrees |
| How many e- domains are in a linear molecular geometry |
| 2 e- domains |
| What is the bond angle for trigonal planar? |
| 120 degrees |
| How many e- domains are in trigonal planar molecular geometry |
| 3 e- domains |
| What is the bond angle for tetrahedrals? |
| 109.5 degrees |
| How many domains are in tetrahedrals? |
| 4 e- domains |
| What are the bond angles for trigonal bipyramidal geometry? |
| 90 120 and 180 degrees depending on which bonds are in question |
| How many e- domains are in trigonal bipyramidal? |
| 5 e- domains |
| What is the bond angle for an octahedral? |
| 90 degres |
| How many e- domains are in an octahedral? |
| 6 e- domains |
| What effect do lone pairs have on the bond angle? |
| Make them slightly smaller |
| How can a compound containing polar bonds be non-polar? |
| If the polar bonds cancel each other out |
| What type of molecules do dipole-dipole interactions occur? |
| Polar molecules |
| What is the relation between polarity and dipole-dipole forces? |
| More polar = larger dipole-dipole |
| Are Ionic and Covalent bonds inter or Intra molecular forces? |
| Intra |
| What type of intermolecular forces do non-polar molecules have? |
| Only london dispersion forces |
| What is ion dipole attraction? |
| molecule completely charged binds to something partially charged |
Rank the following in strength ; Dipole-dipole, hydrogen bonding, ion-dipole, london dispersion |
| Hydrogen bonding, ion-dipole, dipole-dipole, london dispersion |
| How are IMF's related to BP, MP, Viscosity, Surface Tension, and Vapor Pressure |
Higher IMF's = higher BP, MP, Viscosity, and Surface tension. ; Higher IMF's = lower vapor pressure |
| If all molecules are non-polar how do you distinguish between the strongest and weakest IMF strength? |
| The size of the molecule has the largest IMF strength |
| How does an increase in temperature affect the VP? |
| it increases the VP |
| When you lower the pressure how does this affect a molecules boiling point? |
| It lowers the BP |
| What are the two major assumptions for ideal gases? |
1) Gas molecules have no volume 2) No IMF's |
| What is Charles's law? |
| Temp increase leads to volume increase |
| In boyles law, how is volume related to pressure? |
| Inversely proportional |
| What is the partial pressure law equation? |
| Pa = Xa * Ptotal |
| How is KEavg related to temperature? |
| KEavg does NOT change with temperature |
| What is the equation used for Graham's Law of Effusion? |
| R2/R1 = sqrt(molar mass1/molar mass 2) |
| What gas escapes quicker according to Graham's Law of Effusion? |
| The lighter gas |
| What are the 7 diatomic atoms? |
| N, H, F, O, I, Cl, Br |
| How is a supersaturated solution made possible? |
| By heating |
| What is the equation for molality? |
| mol solute/ Kg solvent |
| What is the mol fraction equation? |
| mol A/ tot mol |
| What are the 2 important solubility rules that need to be known? |
1) All group 1 metals, NO3-, NH4+, ClO4-, C2H3O2- salts are SOLUBLE 2) Most Ag+, Pb 2+, Hg2 2+ salts are INSOLUBLE |
| Are solids more soluble at higher or lower temperatures? |
| Higher |
| Are gases more or less soluble at higher temperatures? |
| Less Soluble |
| What is the relationship between gas and pressure? |
| Gases are more soluble at higher pressure |
| What is the equation for freezing point depression? When do you use it? |
Delta T = -i*Kf*m
Use this when trying to figure out the new freezing point when a different solute is added |
| What is the equation for BP elevation? |
| Delta T = i*Kb*m |
| Why do impurities lower the freezing and melting points |
| Because it makes it more difficult to form crystal structures |
| What is the relationship between impurities and IMF's? |
| impurities increase the amount of IMF's |
| How do impurities affect the boiling point? |
| Impurities increase the boiling point |
| What is the Vant Hoff factor? |
| the amount of pieces a compound will split in to |
| What is the vant Hoff factor of Na2SO4? |
| 3 2 Na and 1 SO4 |
| What is the vant Hoff factor for a molecular compound? |
| 1 because it doesn't split |
| How do you calculate the highest BP between .1m NaCl, .08m Al(NO3)3, .2m CH3OH ? |
| Calculate the i*m and the highest number will have the highest boiling point |
| Which law do we use for vapor pressure depression? |
| Raoults Law |
| Why does VP lower with an increase in IMF's? |
| Because more IMF's make it harder for a molecule to escape, thus lower VP |
| What is osmotic pressure? |
| The amount of pressure needed to prevent H2O levels from rising |
| When do you use the vant Hoff factor in calculations? |
| ;If the solute splits |
What are the rate expressions for each of the reactants and products ; 2 NH3 ----> N2 + 3H2 |
Delta [N2]/delta t Delta [H2]/ 3*delta t Delta [NH3]/2*delta t |
| How does the concentration affect the rate of reaction in a 0th, 1st, or 2nd order reaction |
0th- concentration has no effect 1st- concentration is directly proportional to rate 2nd- concentration is squared to get rate |
| Why do chemical reactions slow down over time? |
| Because the concentration decreases |
| What is the shortcut method to finding the rates of certain reactions? |
Find the change in concentration and figure out how much it is multiplied by and set that as 2^x (if concentration is doubled 3^x if tripled). Then go to the rate and figure out the same thing. Set this value = to 2^x
2^x=4 Now solve for X and this will be the order for that concentration and plug it into the equation |
| How do you figure out the overall order of a reaction? |
| Sum the exponents |
| What is a unimolecular, bimolecular, and termolecular reaction |
Unimolecular- 1 reactant molecule Bimoleuclar- 2 reactant molecules termolecular- 3 reactant molecules |
| How is collision frequency and temperature related? |
| increased temperature increases collision frequency |
| What is the equation for the Arrhenius equation? |
| K = Ae^-Ea/RT |
True or False:
Temperature has no effect of the activation energy |
| True |
| How are Ea and K related? |
| As Ea increases, K decreases |
| What are 3 ways to increases the rate of rxn? |
| Increase temperature, Lower Ea, increase [ ] reactants |
| What are 2 ways to increase K? Does the [ ] have any effect? |
Increase temperature, lower Ea.
[ ] has ZERO effect |
| If K >> 1 what is favored at equilibrium? |
| Products |
| If K <<1 what is favored at equilibrium? |
| Reactants |
| If K is ~1 what is favored at equilibrium? |
| Both products and reactants in equal amounts |
| What is an easy way to remember which way the reaction will shift when looking at the difference in K and Q? |
| Write K before Q and which ever direction the arrow points is the direction that the reaction will go. |
| By using K and Q, how can we tell if the reaction is at equilibrium? |
| If K = Q |
| What is the only way the we can change the value of a constant? |
| If we change the temperature |
| If you reverse a reaction, what happens to the reaction constant? |
| You inverse the reaction constant, NOT making it negative! |
| What effect do solids have with Le Chatliers principle? |
| NONE |
| If you increase the pressure of a reaction which way will the reaction shift? |
| To the side with the least amount of moles |
| If you decrease the volume, which way will the reaction shift? |
| To the side with the least amount of moles. |
| According to Le Chatliers Principle, if you increase the temperature is the endothermic or exothermic side favored? |
| Endothermic |
| If Kc= [H2O]/[O2], what will happen to Kc if you add a bunch of O2 and why? |
| Nothing will happen to Kc since it is a constant. However, it will simply be changed to Qc. |
| What is significant about the ion [ ]'s at Ksp? |
| They are the highest ion [ ]'s possible before the ion's precipitate. |
| In a solubility-type reaction, if you add something that can complex with the products, which way will the reaction shift? |
| Right |
| What is the quick cheat for figuring out molar solubility problems and when does it NOT work? |
This ONLY works if NO common ions are present.
Figure out how many ions of each atom that the compound will split into and set the # per atom as a coefficient and exponent. Then solve for X.
Ex) BiI3 Ksp= x*3x^3 = 27x^4 |
How would you go about solving this problem:
What is the solubility of AgCl in 0.1M HCl? Ksp = 1.8*10^-10 |
1st, write the Ksp equation and add 0.1 to the common ion Ksp = x * x+0.1 2nd, assume the x next to the 0.1 is negligible 1.8*10^-10 = x*0.1 3rd, solve for x 1.8*10^-10/0.1=x x=1.8*10^-9 |
| What is the definition of an Arrhenius base? |
| OH- is donor in H2O |
| What is the definition of an Arrhenius Acid? |
| H+ is donor only in H2O |
| What is a Bronsted-Lowry acid? |
| H+ is the donor PERIOD |
| What is a Bronsted-Lowry base? |
| H+ acceptor |
| What is a Lewis Acid? |
| e- acceptor |
| What is a Lewis base? |
| e- donor |
| What is a trick to remember the strong bases? |
| All of Group I and the larger Group II |
| What does it mean for something to be a strong acid? |
| It dissociates 100% |
| What are the 7 strong acids? |
| HCl, HBr, HI, HNO3, HClO4, HClO3, H2SO4 |
| What is the trend for relative strength of a binary acid? |
| To the right and down the periodic table |
| What is the trend of relative strength of oxoacids? |
| More oxygen means more acidic |
| What is a heteroatom in an oxoacid? |
| Any atom other than oxygen |
| How is electronegativity related to the relative strength of an oxoacid? |
| The more electronegative heteroatom, the more acidic the oxoacid |
| What is needed in order to solve for the pH of a weak acid? |
| [ ] and Ka |
| What is the equation required to solve for the pH of a weak acid? |
| Ka = ([H+]*[A-])/[HA] |
| What is the equation required to solve for the pH of a weak base? |
| Kb = ([OH-]*[HA])/[A-] |
| Are acid base neutrilizations endothermic or exothermic? |
| Exothermic |
| How do Ka and Kb relate to acid and base strength, respectively? |
| larger Ka and Kb value mean a stronger acid or base |
| How does pKa or pKb relate to acid or base strength? |
| Larger pKa or pKb value means a weaker acid or base |
| If the value of Kw increases, what happens? |
| If Kw increases the value of the "neutral pH" decreases (becomes more acidic) |
| Which will release more heat, a strong acid w/ a strong base or, a strong acid with a weak base |
| strong acid w/ strong base |
| What are the negligible cations? |
| Group 1 and Group 2 cations |
| What is the relationship between charge and acidity? |
| The higher the positive charge, the more acidic |
| What are the negligible anions? |
| Those who are complements of a strong acid |
| How do basic salts become more soluble? |
| When you add an acid to the solution |
| When asked a question like, "Which of the following compounds is least dependent upon the pH of the solution," what do you look for? |
| You look for the compound that is neutral |
| What are buffers made from? |
| Weak acids and their conjugate bases |
| Which equation would you use to calculate the pH of a buffer solution (name and actual equation)? |
Henderson-Hasselback
pH = pKa + log [A-]/[HA] |
| If the pH of a compound is 3.2, what is the buffering capacity range? |
| 2.2-4.2 |
| What formula do you use to measure the comparative strengths of acidity? |
| 10^x |
| When using the Henderson-Hasselback why do you use moles for the [A-] and [HA]? |
| Because the liters will eventually cancel eachother out so it is perfectly fine to use mols |
| For a strong acid, strong base titration, what pH will the equivalence point be at? |
| 7 |
| For a weak acid, strong base titration, what pH will the equivalence point be at? |
| pH > 7 |
| For a strong acid, weak base titration, what pH will the equivalence point be at? |
| pH <7 |
| If you have a weak acid, strong base titration, why is the pH greaker than 7? |
Because the conjugate base that you form from the weak acid is an actual base and not a neutral salt. The DAT will word it like this, "The weak acid will undergo hydrolysis to form hydroxide"
NOT because a strong base is present vs. a stong acid!! |
| Why is the pH less than 7 in a strong acid, weak base titration? |
| Because the conjugate acid will dissociate and form H+ in to final solution |
| In a SA/SB titraiton curve, what does the initial line look like? |
| straight line |
| How do you solve for the concentration in a titration problem? |
| MOLARITYacid*VOLUMEacid = MOLARITYbase*VOLUMEbase |
| At the 1.2 equivalence point, what is pH equal to? |
| pKa |
| If the pKa is 4, what would make an effective buffer? |
| pka 3-5 |
| What point on a titration curve will always give you the pKa? |
| The 1/2 equivalence point |
| What is the 1st law of thermodynamics? |
| energy is conserved |
| What is the 2nd law of thermodynamics |
| For a spontaneous process, entropy increases |
| What is the 3rd law of thermodynamics? |
| A perfect crystal at 0 kelvin has 0 entropy |
| What is the equation for the change in internal energy? |
Delta E = q + w
OR
Delta E = q-P*delta V |
| If 100 J of heat was transferred from the system to the surrounding and 50 J of work was pperformed on the system. What is delta E? |
-50 J
-100+50=-50 |
From the following equation, how can we tell that delta S is positive?
2C(s) + O2(g) ----> 2CO(g) |
| There is one mole of gas in the reactants vs. 2 moles of gas in the products |
| When a solid is going to a liquid and to a gas, what is the sign of delta S? |
| Positive |
| Can delta S for the system ever be negative, why or why not? |
| Yes, the system can be negative but the summation of the system and the universe must be positive |
| If delta S of the reaction is not given, how could you solve for it? |
| Delta S rxn = (Sigma(n*S products)) - (Sigma(n*S reactants) |
| What does it mean for something to be a state function? |
| It is independent of the pathway meaning it does not depend on the intermediates but ONLY the initial and final states |
| What are the two major NON state functions |
| q and w |
| Is breaking bonds endothermic or exothermic? Forming bonds? |
Breaking- endothermic Forming- exothermic |
| What is the equation for bond enthalpy? |
| Delta H rxn = Delta broken - Delta formed |
| What is the enthalpys of formation measuring? |
| The enthaply it takes to FORM the products |
| What 2 things classify a formation reaction? |
1) 1 mole of product is being formed 2) Reactants are all elements in their standard state |
| What is the standard state of Carbon? |
| C(graphite) |
| What is the Delta H value of any element in their standard state? |
| 0 |
Which of these values changes, if any:
Delta G
Delta G not |
Delta G
Delta G not does not change ever |
What is the equation used to solve for Delta G?
|
| Delta G = Delta G not + RT * ln*Q |
| What is the equation to solve for Delta G not? |
| Delta G not = -RT*lnK |
| What is the equation used to solve for Delta G not of the entire reaction? |
| Delta G not reaction = DGnot products - DGnot reactiants |
True or False:
When at a phase change temperature, the two phases are in equilibrium with one another? |
| True |
| Why does the universe prefer exothermic reactions? |
| Because it lowers the energy required in the universe and makes it more stable |
| How would you solve a free energy problem that is asking for temperature dependence? |
| Set delta G equal to zero and solve the rest |
| What is another name for the oxidant? |
| Oxidizing agent, the compound causing oxidation |
| What is another name for the reductant? |
| The reducing agent, the compound causing reduction |
| In a Galvanic cell, which electrode gets oxidized? |
| The anode |
| Which way does electricity flow in a galvanic cell? |
| Anode -----> Cathode |
| Are galvanic cells spontaneous or non-spontaneous? What is the Ecell (>or<0)? |
| Spontaneous Ecell>0 |
| Does the galvanic cell produce or consume electricity? |
| Produce |
| What is the orientation of polarity of a galvanic cell? Electrolytic cell? |
Galvanic- Anode - Cathode + Electrolytic- Anode + Cathode - |
| Does a galvanic or electrolytic cell have a salt bridge? |
| Galvanic |
| In a Galvanic cell anode, where would you typically find the electrons in the 1/2 reaction? |
| Products |
| In a Galvanic cell cathode, where would you typically find the electrons of the 1/2 reaction? |
| The reactant |
| In a Galvanic cell, which electrode will gain mass? |
| + electrode or Cathode |
| In a Galvanic cell, which electrode will lose mass? |
| The Anode or - electrode |
| In a galvanic cell, how to the salt ions move in the salt bridge and why? |
| Anions to anode and cations to cathode in order to keep neutrality in the solution |
| In a Galvanic cell, where do the electrons flow through, where do the ions flow through? |
e- flows through the wire ions flow through the salt bridge |
| What equation do you use to calculate the standard cell potentials (E not)? |
| E not = E not reduction+ E not oxidation |
| What is the standard potential of a hydrogen atom? |
| 0 |
| Does the amount of moles have any bearing on the standard potential? |
| NO |
| What is the non-standard cell potential equation? |
E = E not - (.0592/n) * log Q
Q = [material in products]/[material in reactants] |
| How can you increase the standard cell potential? |
| Shift the reaction to the right |
| How can you decrease the standard cell potential? |
| Shift the reaction to the left |
| What are the 2 classifications for a reaction to be spontaneous? |
1) The sum of the potentials is positive 2) One molecule is oxidized and one is reduced |
| In a spontaneous reaction what is the relative value of Delta G, Ecell, and K vs Q? |
Delta G <0 Ecell>0 K>Q |
| In electrolysis, which electrode do anions and cations go to, respectively? |
Anions- Anode Cations- Cathode |
| What equation is required to solve electrolysis calculations? |
| (Amp*time(sec))/(n*F)=mol product |
| How can you tell if an element if in its "excitatory" state based off of its electron configuration? |
| Because it skips an entire shell if it is in its excitatory state |
*Need periodic table*
What is the e- configuration for Cu+?
|
| 1s2 2s2 2p6 3s2 3p6 3d10 |
Which of the following is paramagnetic? Why?
Cl-, Ag, Cu+, Mg 2+ |
| Ag because it has an unevenly filled electron configuration (unpaired e-) |
Which of the following is diamagnetic? Why?
Cu+, Fe3+, Ca+ |
| Cu+ because it does not have any unpaired electrons |
| What are the maximum amount of electrons possible in the 3rd shell? |
| 2*3^2 = 18 |
How many orbitals are in the 4th shell?
|
| 4^2 = 16 |
Which of the following is likely to be radioactive? Why?
Mg(24), O(16), Au(196), C(12)
(X) denotes isotope number |
| Au(196) because it is the only choice greater than z>83 |
Which of the following is likely to decay by alpha emission and why?
Ne(23), He(4), Ur(235), C(14) |
| Ur(235) because it fits z>83 |
| What is the product of the gamma emission of (60)Co and Why? |
| (60)Co gamma emission doesn't change protons or neutrons |
Which is most likely to decay by beta emission? Why?
Ca(40), O(16), C(14), N(14) |
| C(14) because n/z is not equal to 1 |
What is the product of the alpha decay of (210)Po?
*Need Periodic Table* |
(210)Po ----> (4)He + (206)X
X = Pb |
| What is the product of e- capture of (20)Na? |
| (0/1)e- + (20)Na -----> (20) Ne |
| Which route of decay converts a proton into a neutron? |
| Both positon emission and e- capture |
Which of the following has the highest 1st ionization energy? Why?
Al, Si, P, S, Mg
*Need Periodic Table* |
P
The exception to the trend is that group 5 is greater than group 6 |
Which of the following has an ionic radius smaller than its corresponding atomic radius?
N, Li, O, Cl |
| Li because Li is the only cation and cations have smaller ionic radii than atomic radii |
Which of the following has the highest e- affinity?
O, N, C, F |
| F |
Which of the following has the highest 2nd ionization energy? Why
Mg, Na, C, Be |
| Na because the highest 2nd ionization energy is the molecule with only one valence e- |
Which of the following has the highest BP and why?
H2O, HOCH2CH2OH, Ar, NaCl, CH3OCH3 |
| NaCl because it is the only ionic molecule |
Highest BP? Why?
HOCH2CH2OH, CH3CH2OH, H2O, NaOH |
| NaOH because it is ionic |
Highest BP? Why?
CH3OH, (CH3)2, CH3F, CH4 |
| CH3OH because it has the most IMF's |
Highest VP?
Kr, Ar, Ne, He |
| He |
Highest BP?
CH3OH, CH3CH2OH, CH3(CH2)F, CH3(CH2)2OH |
| CH3(CH2)2OH because it is the largest molecule with hydrogen bonding |
Which of the following are exothermic and endothermic?
Vaporization, Condensation, Sublimation, Fusion |
Condensation- exothermic
Vaporization, Sublimation, Fusion- endothermic |
| What is deposition? |
| From Gas to Solid |
| What is fusion? |
| From solid to liquid |
| Where/what is the triple point? |
| The point where all there phases meet on a phase diagram |
| Where/what is the critical point on a phase diagram? What does the critical point mean? |
| The furthest point to the right which denotes the point of supersaturation |
| How does a noble gas behave most ideally? |
| With increased temperature and decreased pressure |
Which of the following has the highest KEavg at 25 degrees C?
CO2, Ar, F2, all the same |
| All the same because KEavg is the same for all compounds at the same temperature |
| When you have two different gases in a balloon, which will escape the fastest? |
| The lighter gas |
| At what rate will either O2 or H2 escape quicker? Which element escapes quicker? Which law is required to solve this problem? |
| sqrt(32/2) = 4 times quicker. H2 will escape quicker. We use Graham's law to solve this problem |
True or False:
The gas with the most IMF's will behave most ideally? |
| False, exact opposite |
Which of the following is most likely an ideal gas?
Ne, CO2, H2O, Xe |
| Ne, because it has the least amount of IMF's and it is the lightest while still fulfilling the two major ideal assumptions |
| What increases the solubility of HCl in H2O? (2 things) |
| Decrease temperature, increase pressure |
Which of the following increases BP the most? Why? BaSO4, KCl, CH3OH, CaCl2 |
| CaCl2 because it dissociates into the most ions |
| If Kf = 1.86 and the freezing point = -0.62, what is the molality? |
-1.86 * m = -0.62
m = 0.33 |
Which of the following has the highest freezing point? Why
1.5m CH3CH2OH, 0.7m AlCl3, 1.2m C8NO3, 1m NaCl |
| 1.5m CH3CH2OH becaues it doesn't dissovle and thus has the lowest [ ] of dissolved species |
Which of the following has the highest freezing point?Why?
1.5 m CH3CH2OH, 0.7m AlCl3, 1.2m C8NO3, 1m NaCL |
| 0.7 m AlCl3 because it has the highest [ ] of dissolved species |
| What would be the freezing point of a solution prepared by dissolving 117g of NaCl in 1kg H2O (KF,water=1.86°C/m)? Why? |
| -7.44 because of the vant Hoff factor of 2 thus it would NOT be -3.72 |
|
[image] because valid rate expressions are positive for products and negative for reactants. Thus, choice 1 would be correct if if were 1/5 instead of 5/1 |
| If a second order reactant is increased by a factor of 10 how much is the rate of reaction increased by? |
| 100 |
| If the [ ] of 1st order is doubled and the [ ] of the second order is tripled, what is the overall net rate of reaction? |
2*1=2 3^2=9
9*2=18
18 |
| What are the only things that can affect K? |
| temperature change and catalyst |
In the following equation, what will maximize CO production?
2C(s) + O2(g) ---> 2CO(g) delta H = -566kJ
Decrease the volume, decrease temperature, remove O2, increase pressure |
| Decrease the temperature. Since it is an exothermic reaction, heat is assumed to be a product and if you lower the temperature it will shift the reaction to the right |
| What is the molar solubility of AB3, Ksp = 3.0*10^-19 ? |
3x^3*x = 27x^4=3.0*10^-19
3.0*10^-19/27=x^4 1.0*10^-20=x^4
x=1.0*10^-5 |
What is the Ksp if the molar solubility of MX2 is 2.0*10^-6 M?
|
4x^3=Ksp 4(2.0*10^-6)^3=Ksp
4*8.0*10^-18 = Ksp
Ksp = 3.2*10^-17 |
What is the molar solubility of BaF2 in 0.1M NaF Ksp, BaF2 = 3.2*10^-8
|
3.2*10^-8 = x * 0.1^2
3.2*10^-8/0.1^2 = x
x = 3.2*10^-6 M |
| If Ksp > Qsp, which way does the reaction shift? What is the result (precipitate or not)? |
| Shift right. No ppt occurs |
Which of the following will AgCl be least soluble? Why?
.15M AgNO3, .08M MgCl2, Pure H2O, 0.1M HCl |
| .08M MgCl2 because it has the highest [ ] of common ion with AgCl. |
What is the strongest acid listed here? How do you know?
H2O, H2S, H2Te, H2Se |
| H2Te because it is furthest down the periodic table |
| How much more acidic is pH 1.5 than pH 4.0? |
| 10^2.5 = 300 or so |
| Strong Acid: If [H+] = 2.0*10^-4 M what is the pH? If this were a weak acid, what would be needed to solve this problem? |
-log(2.0*10^-4) = 3.8
If this were for a weak acid, Ka would be needed to solve this problem |
What is the pH of 0.1M HCN (Ka = 5.0*10^-10)?
|
Ka=([H+][A-])/[HA]
5.0*10^-10*0.1=x^2 5.0*10^-11=x^2 -log(5.0*10^-5.5)=x
x=5.2 |
Which of the following has a pH closest to 7 and why?
KClO2, CaCl2, Al(NO3)3, NaHCO3 |
| CaCl2 because both Ca and Cl are negligible ions meaning that it is a neutral salt. |
Which of the following would form a buffer solution and why? .1M HBr and .1M KBr .1M HClO4 and .1M KOH .1M HClO2 and .1M NaClO2 .1M HF and .1M NaOH |
| .1M HClO2 and .1M NaClO2 because this is the only choice that contains a weak acid (HClO2) and its conjugate base (NaClO2) |
What is the pH of a solution with .05M HF and .05M NaF Ka, HF = 6.8*10^-4
|
.05/.05 = 1 so pH = pKa -log6.8*10^-4 = pKa
pKa=pH=3.2 |
What is the pH of a solution containing .003M HF and .02M NaF? Ka, HF = 6.8*10^-4 |
pH = pKa + log[A-]/[HA] pKa=-logKa=3.2 .02/.003 = 6.67*10^1 log6.67*10^1=.8
3.2+.8 = 4.0 |
How much heat is released when 120 grams of Ca(s) reacts with O2 Delta H not = -1271 kJ
2Ca(s) + O2 (g) ---> 2CaO(s) |
120g*(1/40g)*(1271/2mol Ca) = 1.5
1271*1.5 = 1907 kJ |
| When is entropy change observed at a value of close to zero? |
| When the moles of gas in the products and reactants are the same |
Which of the following is a formation reaction? Why?
C + O2 (g) ----> CO2(g) N2(g) + H2(g) ---> 2NH3(g) C+CO2(g) --->2CO(g) 1/2 H2(g) + 1/2 N2(g) + 3/2 O2(g) --->HNO3(g) |
1/2 H2(g) + 1/2 N2 (g) + 3/2 O2(g) ---> HNO3(g)
because all of the reactants are in their standard state and there is only one mole of product |
Which of the following is false about an electrolytic cell and why?
E is consumed, e- from anode to cathode, oxidation @ cathode, electricity is used |
| oxidation occurs at cathode because the cathode has a negative charge so the more positive species will be attracted to the cathode. Thus, it will gain electrons fitting the definition of being reduced |
| What are the products of molten electrolysis of NaCl? |
| Na and Cl2 |
| What is the 1/2 reaction at the CATHODE for the molten electrolysis of CdCl2? |
| Cd2+ + 2e- ---> Cd |
How many moles of e- are produce by the electrolysis of NiCl2 using 10 Amps for 30 min. F=96500
(Not exact number just the intermediate step to solve for the answer) |
| 10 * 1800/(2*96500) = # moles |
| Metals are said to be malleable and ductile. What do each of these mean, respectively? |
Malleable- deformed w/o breaking ductile- drawn into wires |
| What is Dalton's Law? |
| Total pressure is the sum of all the partial pressures |
