Search found 110 matches
- Thu Mar 12, 2020 6:14 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle
- Replies: 4
- Views: 410
Re: Le Chatelier's Principle
it basically predicts a system's behavior or "reaction" to certain kinds of stress (or changes) including increasing/decreasing temperature or pressure and increasing/decreasing the concentration of a specific substance; the system could shift either way based on the stress.. -increasing t...
- Tue Mar 10, 2020 9:33 pm
- Forum: *Enzyme Kinetics
- Topic: Poison a Catalyst
- Replies: 3
- Views: 283
Re: Poison a Catalyst
it's important to know that it means a catalyst is no longer active and cannot function in speeding up a reaction; this could occur due to exposure to certain chemicals
- Tue Mar 10, 2020 6:31 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: catalysts in balanced equations
- Replies: 6
- Views: 478
Re: catalysts in balanced equations
Jacob Motawakel wrote:So if the catalyst is not present in the products of the final reaction, does that mean it is fully consumed throughout the overall reaction?
a catalyst only speeds up a reaction, but it is NOT consumed!
- Mon Mar 09, 2020 11:31 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Adsorption
- Replies: 7
- Views: 384
Re: Adsorption
805312064 wrote:Okay that makes sense. One more question, what does adhesion/adsorption have to do with catalysts?
it is a term used in heterogeneous catalysis where it is the process by which a catalyst binds (=sits) to surface atoms that are in a different phase than that of the catalyst
- Mon Mar 09, 2020 11:22 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Adsorption
- Replies: 7
- Views: 384
Re: Adsorption
another term used to describe this would be adhesion (ex; a substance adhering to a surface)
- Mon Mar 09, 2020 11:20 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: endothermic reaction
- Replies: 5
- Views: 397
Re: endothermic reaction
if you mean the part of the reaction (reactants or products) in which heat would be written;
with reactants if delta H is + (meaning reaction is endothermic, thus absorbing heat)
with products if delta H is - (meaning reaction is exothermic, thus releasing heat)
with reactants if delta H is + (meaning reaction is endothermic, thus absorbing heat)
with products if delta H is - (meaning reaction is exothermic, thus releasing heat)
- Fri Mar 06, 2020 1:06 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Inert electrode
- Replies: 9
- Views: 538
Re: Inert electrode
whenever there isn’t a solid that would be able to conduct electricity in the oxidation/reduction half-reactions, add Pt(s)
p.s. Hg(l) is an expection as it can conduct electricity, so no need to add Pt(s)
p.s. Hg(l) is an expection as it can conduct electricity, so no need to add Pt(s)
- Fri Mar 06, 2020 1:01 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Units G=-nFE
- Replies: 6
- Views: 816
Re: Units G=-nFE
1 Volt = 1 J/C so the units cancel out when you multiply;
substituting the units in for -nFE, you get
-(mol)x(C/mol)x(V=J/C), and you’re left with J for G
substituting the units in for -nFE, you get
-(mol)x(C/mol)x(V=J/C), and you’re left with J for G
- Fri Mar 06, 2020 12:47 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Adding Pt(s) to a Cell Diagram
- Replies: 14
- Views: 819
Re: Adding Pt(s) to a Cell Diagram
Platinum (Pt(s)) is adder to the cell diagram whenever the oxidation/reduction half-reactions do not have a solid to conduct electricity.
Hg(l) is an exception since it can conduct electricity, so Pt(s) is not needed.
Hg(l) is an exception since it can conduct electricity, so Pt(s) is not needed.
- Tue Mar 03, 2020 12:20 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: lnQ vs logQ
- Replies: 5
- Views: 334
Re: lnQ vs logQ
Yes, I believe it would just depend on which constants you use; so remember that lnQ and logQ are not the same!
- Tue Mar 03, 2020 12:14 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Units for n
- Replies: 5
- Views: 376
Re: Units for n
n is calculated in the unit of mole (abbreviated; mol)
- Thu Feb 27, 2020 8:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cells
- Replies: 5
- Views: 352
Re: cells
galvanic cells (including concentration cells) always have a positive voltage as they have favorable redox reactions (=spontaneous), while electrolytic cells have a negative voltage as they have unfavorable redox reactions (=nonspontaneous) and must be driven by an external power source
- Thu Feb 27, 2020 8:21 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration Cells
- Replies: 6
- Views: 503
Re: Concentration Cells
both concentration and galvanic cells are batteries in which the redox reaction has a positive voltage, however;
concentration cells have the same chemical species (with different concentrations) while galvanic cells have different chemical species
concentration cells have the same chemical species (with different concentrations) while galvanic cells have different chemical species
- Tue Feb 25, 2020 6:58 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode and Cathode
- Replies: 4
- Views: 354
Re: Anode and Cathode
anode is the electrode where oxidation occurs and cathode is the electrode where reduction occurs;
electrons flow from anode (-) to cathode (+)
electrons flow from anode (-) to cathode (+)
- Mon Feb 24, 2020 10:14 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: electrolytic cells
- Replies: 3
- Views: 304
Re: electrolytic cells
electrolytic cells are used in the process of electrolysis which drives a non-spontaneous redox reaction to decompose chemical compounds using electrical energy
- Mon Feb 24, 2020 10:11 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Difference in G's
- Replies: 2
- Views: 206
Re: Difference in G's
I believe the only difference is that ΔG° is ONLY in standard conditions (like it is constant/unchanging for specific measures), however ΔG is not specific, it changes depending on other variables!
- Wed Feb 19, 2020 11:09 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode and Cathode position
- Replies: 5
- Views: 315
Re: Anode and Cathode position
just to make sure, you can double check to see which side is oxidized/negative (=anode) and which side is reduced/positive (=cathode)
- Wed Feb 19, 2020 11:05 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode and Cathode
- Replies: 6
- Views: 394
Re: Anode and Cathode
electrons always flow from the anode (-) to the cathode (+)
in other words, electrons always flow from the oxidation half cell to the reduction half cell.
in other words, electrons always flow from the oxidation half cell to the reduction half cell.
- Wed Feb 19, 2020 11:01 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Potential difference between electrodes
- Replies: 3
- Views: 273
Re: Potential difference between electrodes
I am not too sure, but I hope this helps a little;
E is the electromotive force (EMF) which equals the potential difference when there is no current flow,
since i represents current, it shows that as the current tends to 0, the potential difference is at a maximum.
E is the electromotive force (EMF) which equals the potential difference when there is no current flow,
since i represents current, it shows that as the current tends to 0, the potential difference is at a maximum.
- Wed Feb 19, 2020 10:51 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Battery Dying
- Replies: 4
- Views: 298
Re: Battery Dying
a battery would die at equilibrium because there will no longer be a flow of charge/electrons between the anode and cathode; using a salt bridge (or porous disk) would prevent that
- Wed Feb 19, 2020 10:45 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Gibbs free energy
- Replies: 9
- Views: 681
Re: Gibbs free energy
ΔG denotes conditions that are not at standard state
ΔG° denotes conditions that are at standard state
*standard state: 1 M, 1 atm, and 298 K (= 25°C)
ΔG° denotes conditions that are at standard state
*standard state: 1 M, 1 atm, and 298 K (= 25°C)
- Thu Feb 13, 2020 10:23 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: reaction entropy
- Replies: 7
- Views: 570
Re: reaction entropy
we use, ΔS° = ΣS°(products) - ΣS°(reactants), and i think we can also calculate ΔS using some of the formulas found on the formula sheet, but that depends on what is known/unknown and the system of the reaction
- Thu Feb 13, 2020 9:57 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4.15
- Replies: 1
- Views: 321
Re: 4.15
when calculating ΔH(rxn), we find that all except for ΔH(zinc) in the products is not in its most stable state and therefore not equal to 0. zinc is also the limiting reagent in that reaction, after finding ΔH(rxn) multiply it by moles of zinc which you can find by dividing by molar mass of zinc. th...
- Thu Feb 13, 2020 9:40 pm
- Forum: Ideal Gases
- Topic: initial values
- Replies: 6
- Views: 469
Re: initial values
usually in the question, the initial values are given for both P and V, so make sure to use all the initial values (of all variables) at once in the equation to find n
- Thu Feb 13, 2020 9:37 pm
- Forum: Phase Changes & Related Calculations
- Topic: Relation to entropy?
- Replies: 4
- Views: 329
Re: Relation to entropy?
from lecture notes; "molecules in gaseous phase occupy many more states than liquid and solid"
W(g) > W(l) > W(s) and since S = Kbxln(W) then S(g) > S(l) > S(s)
W(g) > W(l) > W(s) and since S = Kbxln(W) then S(g) > S(l) > S(s)
- Thu Feb 13, 2020 9:33 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: How do I do? [ENDORSED]
- Replies: 2
- Views: 192
Re: How do I do? [ENDORSED]
Gibbs Free Energy can be calculated by using:
1) ∆G = ∆H – T∆S
2) ∆G = – RT ln(K)
3) ∆G = sum of G(products) - sum of G(reactants)
4) Hess's Method (adding or subtracting ∆G(rxn))
1) ∆G = ∆H – T∆S
2) ∆G = – RT ln(K)
3) ∆G = sum of G(products) - sum of G(reactants)
4) Hess's Method (adding or subtracting ∆G(rxn))
- Thu Feb 06, 2020 1:36 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta U equals zero
- Replies: 7
- Views: 315
Re: Delta U equals zero
it would be for an isothermal reaction when the temperature is constant
- Thu Feb 06, 2020 1:31 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Insulated system
- Replies: 5
- Views: 259
Re: Insulated system
we can relate insulation to the effects of temperature on entropy; if a system is insulated, heat cannot be transferred (so temperature won't increase), and therefore there won't be a change in entropy.. hence we can focus instead on how the pressure and volume of such a system would affect entropy
- Tue Feb 04, 2020 6:21 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Statistical Entropy
- Replies: 1
- Views: 69
Re: Statistical Entropy
in general, entropy is a measure of randomness
statistical is when you measure the randomness based on the different microstates that affects entropy
thermodynamic is when you measure the randomness based on the heat transfer that affects entropy
statistical is when you measure the randomness based on the different microstates that affects entropy
thermodynamic is when you measure the randomness based on the heat transfer that affects entropy
- Tue Feb 04, 2020 12:22 am
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Reversible Reactions
- Replies: 1
- Views: 55
Re: Reversible Reactions
reversible reactions are when the reactants that formed the products can go back the other way, so that the products can reform the reactants however, that is not possible for irreversible reactions, where the products cannot reform their reactants (for example, most combustion reactions) in other w...
- Tue Feb 04, 2020 12:18 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat capacity
- Replies: 3
- Views: 113
Re: Heat capacity
heat capacity is the amount of heat energy required to raise the temperature of 1 g of a substance by 1 K constant volume heat capacity; there is no work of expansion, so all heat is contained and used to raise the temperature constant pressure heat capacity; there is work of expansion, so some of t...
- Wed Jan 29, 2020 6:09 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: memorize
- Replies: 6
- Views: 239
Re: memorize
I believe some of the important ones are already included on the formula sheet
- Wed Jan 29, 2020 6:05 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Deriving Equation
- Replies: 3
- Views: 98
Re: Deriving Equation
delta U = delta H - P delta V comes from the equation U = q + w
since q = delta H (change in enthalpy), and w = - P delta V,
when you plug those in instead of q and w, you will get delta U = delta H - P delta V
since q = delta H (change in enthalpy), and w = - P delta V,
when you plug those in instead of q and w, you will get delta U = delta H - P delta V
- Wed Jan 29, 2020 6:01 pm
- Forum: Phase Changes & Related Calculations
- Topic: energy of a system
- Replies: 4
- Views: 174
Re: energy of a system
Before releasing the compressed air, the system will have a high internal energy due to the high pressure inside. After releasing, there will be a work of expansion on the surroundings, and this in turn will decrease the internal energy of the system. In other words, the system loses energy.
- Tue Jan 28, 2020 11:52 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Delta T
- Replies: 4
- Views: 168
Re: Delta T
an exothermic reaction will release heat which will raise the temperature of the surroundings and an endothermic reaction will therefore do the opposite if heat is released for exothermic rxns why is delta t negative? for exothermic reactions, delta T is positive as temperature increases (due to th...
- Tue Jan 28, 2020 11:50 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Delta T
- Replies: 4
- Views: 168
Re: Delta T
delta T (change in temperature) calculated for a system shows whether a reaction is endothermic (absorbs energy) or exothermic (releases energy) if a reaction is endothermic, it absorbs the heat energy, therefore decreases (-) the overall temperature of the system if a reaction is exothermic, it rel...
- Fri Jan 24, 2020 4:51 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Steam
- Replies: 5
- Views: 127
Re: Steam
steam has "stored" energy in its molecules as they move freely;
when steam condenses upon contact with skin, it release said energy because of the difference in temperatures
simply put, steam can cause severe burns due to its high heat energy
when steam condenses upon contact with skin, it release said energy because of the difference in temperatures
simply put, steam can cause severe burns due to its high heat energy
- Fri Jan 24, 2020 4:19 pm
- Forum: Ideal Gases
- Topic: Inert Gas
- Replies: 12
- Views: 660
Re: Inert Gas
inert gas is another term used for noble gas as these gases do not undergo chemical reactions under a set of given conditions (=unreactive)
- Fri Jan 24, 2020 4:13 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Pressure and Enthalpy
- Replies: 5
- Views: 111
Re: Pressure and Enthalpy
when pressure increases, enthalpy increases; and when pressure decreases, enthalpy decreases
- Fri Jan 24, 2020 4:10 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: pka
- Replies: 4
- Views: 271
Re: pka
the higher the pKa, the weaker the acid (less acidic)
- Fri Jan 24, 2020 4:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Percent Ionization
- Replies: 12
- Views: 502
Re: Percent Ionization
% ionization = (acid ionized/initial acid) x 100%
so the value of x divided by the initial molarity, multiplied by a 100%
so the value of x divided by the initial molarity, multiplied by a 100%
- Fri Jan 17, 2020 7:01 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: 6B.9
- Replies: 1
- Views: 173
Re: 6B.9
I'm not sure, but your answer is the same as what I am getting!
6.67x10^-15 seems right because Kw = [H3O+][OH-] = 10^-14
and when you multiply the concentrations, you only get the right value if you use 6.67x10^-15 instead of 1.50x10^-14
6.67x10^-15 seems right because Kw = [H3O+][OH-] = 10^-14
and when you multiply the concentrations, you only get the right value if you use 6.67x10^-15 instead of 1.50x10^-14
- Fri Jan 17, 2020 6:51 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Exercise 6A.19
- Replies: 4
- Views: 146
Exercise 6A.19
6A.19 is asking to calculate the molar concentration of OH- given the molar concentration of H3O+, in part c) [H3O+] = 3.1 mol.L^-1 using [H3O+] [OH-] = 10^-14 (Kw), i keep getting 3.2 x 10^-15 mol.L^-1 (i checked that it is 3.2 x 10^-12 mol.L^-1 in the solution manual) would that be a solution manu...
- Fri Jan 17, 2020 6:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Different types of acids/bases
- Replies: 3
- Views: 122
Re: Different types of acids/bases
Bronsted-Lowry Acid: H+ donor
Bronsted-Lowry Base: H+ acceptor
Arrhenius Acid: produces H+ in H2O
Arrhenius Base: produces OH- in H2O
Lewis Acid: electron pair acceptor
Lewis Base: electron pair donor
hope this helps a little!
Bronsted-Lowry Base: H+ acceptor
Arrhenius Acid: produces H+ in H2O
Arrhenius Base: produces OH- in H2O
Lewis Acid: electron pair acceptor
Lewis Base: electron pair donor
hope this helps a little!
- Fri Jan 17, 2020 6:29 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pH for weak acids
- Replies: 5
- Views: 431
Re: pH for weak acids
pH is a measure of the concentration of H3O+ or H+, so it basically measures the concentration of hydronium ions in a solution. strong acids dissociate/ionize way more compared to weak acids, and therefore release more H+. since pH measures the concentration of H+ in the solution; 1. stronger acids ...
- Wed Jan 15, 2020 2:22 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating Q
- Replies: 16
- Views: 700
Re: Calculating Q
We calculate Q the same way we calculate K, and we account for both aqueous and gaseous states. However, liquids and solids are disregarded when calculating the constants. The only difference is that Q indicates the change in the reaction/system at any time before reaching equilibrium, but K is at e...
- Wed Jan 15, 2020 2:12 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5.39
- Replies: 1
- Views: 89
Re: 5.39
Solution Manual Errors (7th Edition) have been posted on Professor Lavelle’s website:
https://lavelle.chem.ucla.edu/wp-conten ... rs_7Ed.pdf
I’m not quite sure where you made a mistake, but if you don’t find the error in this PDF, try to solve it again.
https://lavelle.chem.ucla.edu/wp-conten ... rs_7Ed.pdf
I’m not quite sure where you made a mistake, but if you don’t find the error in this PDF, try to solve it again.
- Fri Jan 10, 2020 4:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Exercise 5G.1
- Replies: 4
- Views: 208
Exercise 5G.1
5G.1 is true/false c) if one starts with a higher pressure of reactant, the equilibrium constant will be larger d) if one starts with a higher concentrations of reactants, the equilibrium concentrations of the products will be larger my question is, why is c) false and why is d) true, what would the...
- Fri Jan 10, 2020 3:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: PCl5 example in lecture
- Replies: 2
- Views: 116
PCl5 example in lecture
During today's lecture, a student asked what would we change X to if PCl3 had a stoichiometric coefficient of 2 instead of 1, I think Professor Lavelle said that it would be 2X. Is that right? (I wanted to check if my notes were correct!) Also, when would it be 2X^2 for PCl3? (he mentioned it, but I...
- Fri Jan 10, 2020 3:16 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: K vs Q
- Replies: 9
- Views: 1634
K vs Q
can someone please explain the reason why when;
1) Q<K, there is more reactant
2) Q>K, there is more product
anything explaining what results in Q<K or Q>K would help!
1) Q<K, there is more reactant
2) Q>K, there is more product
anything explaining what results in Q<K or Q>K would help!
- Fri Jan 10, 2020 3:12 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Example 5I.4
- Replies: 4
- Views: 144
Re: Example 5I.4
If you mean why we have to use partial pressure, it's because the question mentions that they're in a gas-phase equilibrium. We use partial pressure for gases.
- Fri Jan 10, 2020 2:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K expression involving solids/liquids
- Replies: 7
- Views: 248
K expression involving solids/liquids
why do we not include the concentrations of solids or liquids in the equilibrium constant expression, k?
* do we only account for concentrations in the aqueous state?
* do we only account for concentrations in the aqueous state?
- Fri Dec 06, 2019 11:23 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: HW 9C.9
- Replies: 2
- Views: 220
Re: HW 9C.9
to help you figure those out, you must know that;
in c (en) = bidentate
in d (edta) = hexadentate
*count as binding sites to get the coordination number
in c (en) = bidentate
in d (edta) = hexadentate
*count as binding sites to get the coordination number
- Fri Dec 06, 2019 11:18 pm
- Forum: Dipole Moments
- Topic: London Dispersion Forces
- Replies: 5
- Views: 400
Re: London Dispersion Forces
yes, every molecule has london dispersion forces
- Tue Dec 03, 2019 12:34 am
- Forum: Naming
- Topic: Cobalt vs Cobaltate
- Replies: 3
- Views: 211
Re: Cobalt vs Cobaltate
we only add the suffix -ate to indicate that the coordination compound has a net negative charge
- Mon Dec 02, 2019 11:47 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: H2O as a monodenate ligand
- Replies: 1
- Views: 66
Re: H2O as a monodenate ligand
I believe it's because both lone pairs are on the same (one) oxygen atom, so there would only be one binding site for the metal (since in this case, the metal would only bind to one atom)
- Mon Dec 02, 2019 11:41 pm
- Forum: Naming
- Topic: [CO(SO4)(NH3)5]+
- Replies: 2
- Views: 1162
Re: [CO(SO4)(NH3)5]+
pentaamminesulfatocobalt (III) ion
- Wed Nov 27, 2019 12:30 am
- Forum: Lewis Acids & Bases
- Topic: Identifying Acids and Bases
- Replies: 8
- Views: 435
Re: Identifying Acids and Bases
in addition to the answer above, I have noticed two more things:
weak acids usually have carbon or phosphorus in them (ex. carboxyl group COOH)
weak bases usually have nitrogen in them (ex. amine group NH2 or NH3)
but again, this ISN'T a guideline you should always depend on!
weak acids usually have carbon or phosphorus in them (ex. carboxyl group COOH)
weak bases usually have nitrogen in them (ex. amine group NH2 or NH3)
but again, this ISN'T a guideline you should always depend on!
- Wed Nov 27, 2019 12:03 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: 9c7
- Replies: 1
- Views: 156
Re: 9c7
a chelate consists of a central metal atom binding to a ligand (polydentate: meaning it has multiple binding sites) in a ring structure *a ligand can only chelate a metal atom if it has multiple binding sites (=polydentate) p.s. in that specific question, you must know that the binding sites must be...
- Tue Nov 26, 2019 11:41 pm
- Forum: Lewis Acids & Bases
- Topic: Neutralization reaction
- Replies: 1
- Views: 120
Re: Neutralization reaction
**i noticed this was question J.7 (b) zinc nitrite (not zinc nitrate) a neutralization reaction is a reaction between an acid and a base to produce a salt and water we know the products: the salt produced is zinc nitrite which is written as Zn(NO2)2 and water H2O now, we have to figure out the acid ...
- Tue Nov 26, 2019 11:09 pm
- Forum: Lewis Acids & Bases
- Topic: writing chemical equation
- Replies: 1
- Views: 120
Re: writing chemical equation
that appears to be the net chemical equation
C5H5NHCl dissociates and forms Cl- ions that appear on both sides of the equation, but because the Cl- ions don't affect the overall interaction with water, they would be "removed" from both sides in the net chemical equation
C5H5NHCl dissociates and forms Cl- ions that appear on both sides of the equation, but because the Cl- ions don't affect the overall interaction with water, they would be "removed" from both sides in the net chemical equation
- Tue Nov 26, 2019 11:01 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic spectroscopy vs. molecular spectroscopy
- Replies: 1
- Views: 235
Re: Atomic spectroscopy vs. molecular spectroscopy
I think it's actually the same concept for both, but the difference would be;
atomic spectroscopy: of atoms (a single atom)
molecular spectroscopy: of molecules (two or more atoms)
atomic spectroscopy: of atoms (a single atom)
molecular spectroscopy: of molecules (two or more atoms)
- Thu Nov 21, 2019 12:37 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Homework 3F3
- Replies: 5
- Views: 329
Re: Homework 3F3
even if you put them opposite to each other, remember that tetrahedral structures have bond angle 109.5 degrees, and so they won't even be in complete symmetry to cancel the dipole moments here's a tip; all carbon atom tetrahedral structures are polar, unless the carbon atom is surrounded by 4 atoms...
- Tue Nov 19, 2019 6:16 pm
- Forum: Hybridization
- Topic: Hybridization of H2
- Replies: 2
- Views: 2211
Re: Hybridization of H2
hybridization is a concept used for mixing or overlapping s and p orbitals, and since hydrogen only has a 1s orbital, it doesn't hybridize.
- Tue Nov 19, 2019 6:10 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Drawing dipoles
- Replies: 3
- Views: 241
Re: Drawing dipoles
the arrow/dipole points towards the δ- charge
- Tue Nov 19, 2019 6:08 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E.19
- Replies: 2
- Views: 186
Re: 2E.19
Be would form two bonds (one with each CH3).
If it asked about the shape with respect to the central atom (Be), it would be linear (this would also be the shape of the overall structure).
BUT,
If it asked about the shape with respect to the carbon atom, it would be tetrahedral.
If it asked about the shape with respect to the central atom (Be), it would be linear (this would also be the shape of the overall structure).
BUT,
If it asked about the shape with respect to the carbon atom, it would be tetrahedral.
- Tue Nov 19, 2019 4:38 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: diethyl ether and butanol
- Replies: 1
- Views: 96
Re: diethyl ether and butanol
because diethyl ether can't form hydrogen bonds with other diethyl ether molecules, but butanol can, and so the more the intermolecular forces, the bigger the attraction, and it gets harder to break the molecules apart (leading to a higher boiling point)
- Fri Nov 15, 2019 8:34 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 3
- Views: 172
Bond Angles
can someone please explain why bond angles may differ slightly for molecules with the same formula and general shape?
thanks in advance!
thanks in advance!
- Fri Nov 15, 2019 8:27 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: clouds of electrons
- Replies: 3
- Views: 201
Re: clouds of electrons
I believe you would count that as a one region of electron density
- Tue Nov 12, 2019 5:33 pm
- Forum: Octet Exceptions
- Topic: Octet Exceptions
- Replies: 2
- Views: 264
Re: Octet Exceptions
H and He only require 2 electrons for their highest energy shell to be full (they only have 1s that needs to be filled with only 2 electrons rather than 8). Li and Be are metals that tend to lose electrons rather than gain them to get a positive charge, hence going back to the lower noble gas config...
- Tue Nov 12, 2019 5:29 pm
- Forum: Bond Lengths & Energies
- Topic: Bond lengths in molecules
- Replies: 7
- Views: 460
Re: Bond lengths in molecules
bond length in increasing order is: triple bond < double bond < single bond
- Tue Nov 12, 2019 4:45 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: melting points
- Replies: 5
- Views: 170
Re: melting points
NaCl is an ionic bond, HCl is a covalent bond. Ionic bonds are stronger than coverlet bonds, and due to the higher attractions, they have a higher melting point.
- Thu Nov 07, 2019 2:34 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: London Forces
- Replies: 1
- Views: 133
Re: London Forces
yes, because the rod-shaped molecules have a greater surface area than spherical-shaped molecules, allowing more contact points for attraction forces between molecules (more attraction forces = stronger).
- Thu Nov 07, 2019 2:28 pm
- Forum: SI Units, Unit Conversions
- Topic: Kj
- Replies: 6
- Views: 492
Re: Kj
yes, kilo is always 10^3 in unit conversions. 1 kJ = 1000 J.
- Thu Nov 07, 2019 2:26 pm
- Forum: SI Units, Unit Conversions
- Topic: Photons
- Replies: 3
- Views: 322
Re: Photons
eV (electron volt) is a unit of energy which equals to approximately 1.602×10−19 J, and is commonly used to measure the energy of particles including photons.
- Thu Nov 07, 2019 2:23 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Dispersion forces
- Replies: 6
- Views: 215
Re: Dispersion forces
polarizability is the measure of how easily the electron cloud is distorted, so the higher the polarizability, the stronger the dispersion force because the larger electron clouds allow for more effective overlap resulting in a higher attraction between the molecules.
- Thu Nov 07, 2019 2:10 pm
- Forum: Trends in The Periodic Table
- Topic: Polarizability
- Replies: 4
- Views: 292
Re: Polarizability
generally the trend for polarizability is related to the atomic radii trend; it increases down a group and decreases across a period on the periodic table.
the larger the anion, the more polarizable; they would be arranged like so O2-<N3-<Cl-<Br-
the larger the anion, the more polarizable; they would be arranged like so O2-<N3-<Cl-<Br-
- Wed Oct 30, 2019 11:31 pm
- Forum: Trends in The Periodic Table
- Topic: Does H have the highest ionization energy?
- Replies: 4
- Views: 146
Re: Does H have the highest ionization energy?
ionization energy increases across a period and decreases down a group, so if you look at the periodic table it is clear that helium is the element that has the highest first ionization energy
- Wed Oct 30, 2019 11:19 pm
- Forum: Resonance Structures
- Topic: dislocation
- Replies: 1
- Views: 164
Re: dislocation
Do you mean delocalization of electrons? If yes, it is when the electric charge is spread over the atoms in a certain bond (usually over a few of the atoms and not all of them) as the electrons can move freely and transfer within the structure. For example, in the Lewis structure of CN2(2-) rather t...
- Tue Oct 29, 2019 7:27 pm
- Forum: Ionic & Covalent Bonds
- Topic: Strength of ionic and covalent bonds
- Replies: 2
- Views: 94
Re: Strength of ionic and covalent bonds
Generally, ionic bonds are stronger than covalent bonds as they are harder to break.
Double bonds are stronger than single bonds as they are shorter (the shorter the bond, the stronger).
Double bonds are stronger than single bonds as they are shorter (the shorter the bond, the stronger).
- Tue Oct 29, 2019 7:25 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: FC Charge and Stability
- Replies: 2
- Views: 242
Re: FC Charge and Stability
Yes, for example when a compound has an overall charge on it like the 2- in SO3(2-); where the sulfur and one of the oxygen atoms will have a formal charge of 0 , and the other two atoms of oxygen will have a formal charge of -1 each. We must try to get the FC that is closest to zero to make sure it...
- Tue Oct 29, 2019 7:12 pm
- Forum: Octet Exceptions
- Topic: Can P,S,Cl have less than 8 electrons?
- Replies: 3
- Views: 165
Re: Can P,S,Cl have less than 8 electrons?
I think they could, but they wouldn't be stable then! Since they can use their d-orbitals to expand on the octet rule, these elements can have more than 8 valence electrons to be in their most stable form.
- Fri Oct 25, 2019 1:57 pm
- Forum: Ionic & Covalent Bonds
- Topic: Resonance
- Replies: 7
- Views: 314
Re: Resonance
Can someone explain what resonance is and what the importance of it is? Resonance is a way of describing bonding that might form different structures of a certain molecule or ion where the chemical connectivity is the same but the electrons are distributed differently around the structure. It basic...
- Thu Oct 24, 2019 6:59 pm
- Forum: Trends in The Periodic Table
- Topic: Aufbau Principle
- Replies: 11
- Views: 562
Re: Aufbau Principle
What kind of questions might there be regarding the Aufbau Principle on a test? Questions regarding the electron configurations of elements. So you must be able to know the principles in order to determine the correct electron configurations or to figure out whether or not the electron is in a grou...
- Mon Oct 21, 2019 8:46 pm
- Forum: Trends in The Periodic Table
- Topic: 2nd Ionization Energy
- Replies: 7
- Views: 349
Re: 2nd Ionization Energy
It is much easier to remove an electron from a neutral atom using the first ionization energy, however, after you take the first electron, the atom becomes positive in charge. The positive charge of the atom creates a higher attraction that becomes rather hard to break apart. Therefore, it requires ...
- Mon Oct 21, 2019 8:29 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electrostatic potential energy
- Replies: 2
- Views: 214
Re: Electrostatic potential energy
This is the equation used to show the electrostatic (Coulomb) potential energy for multi-electron atoms (basically non-hydrogen atoms). Each q indicates a charge (typically different level charges), and the r is the distance between the charges. The equation shows that the charges and the distance b...
- Mon Oct 21, 2019 8:25 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity Trends
- Replies: 5
- Views: 580
Electron Affinity Trends
I know that atomic radii increase down a group, but decrease across a period; and ionization energy decrease down a group, but increase across a period.
My question is what is the case for electron affinity? What would be the trend down a group and across a period? And why?
Thanks in advance!
My question is what is the case for electron affinity? What would be the trend down a group and across a period? And why?
Thanks in advance!
- Wed Oct 16, 2019 7:11 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals
- Replies: 4
- Views: 143
Re: Orbitals
These can be described by quantum numbers; specifically the magnetic quantum number (ml). The Px, Py, and Pz describe the orientation (on the 3D axis).
For example; Px has ml = -1, Py has ml = 1, and Pz has ml = 0.
Hope that helps!
For example; Px has ml = -1, Py has ml = 1, and Pz has ml = 0.
Hope that helps!
- Wed Oct 16, 2019 7:01 pm
- Forum: Properties of Electrons
- Topic: Question About Electron State
- Replies: 3
- Views: 93
Re: Question About Electron State
It's basically the orbital. The 2 is the shell (energy and size) determined by the principle quantum number (n), the p is the subshell (shape) determined by the angular momentum quantum number (l), the x is the orbital (orientation) of a subshell determined by the magnetic quantum number (ml).
- Tue Oct 15, 2019 10:58 pm
- Forum: Properties of Light
- Topic: Homework help
- Replies: 4
- Views: 121
Re: Homework help
use the following equation; λ = h/mv to find the wavelength.
m is mass of electron which = 9.109 x 10^-31 kg
v is the speed given which = 3.6 x 10^6 m/s
m is mass of electron which = 9.109 x 10^-31 kg
v is the speed given which = 3.6 x 10^6 m/s
- Tue Oct 15, 2019 3:34 pm
- Forum: DeBroglie Equation
- Topic: 1B.27
- Replies: 1
- Views: 133
Re: 1B.27
We're actually supposed to use Δv= 10, there's an error in the solutions manual for this question!
- Tue Oct 15, 2019 3:30 pm
- Forum: DeBroglie Equation
- Topic: 1B.9 HW Question
- Replies: 8
- Views: 210
Re: 1B.9 HW Question
You first convert the Watts to Joules of energy by multiplying 32 Watts (J.s^-1) by time which is 2 seconds; the units cancel and you're left with Joules of total energy (lamp). Then use E = hc/λ to find the energy of a photon. Now you can divide the total energy (64 J) by the energy of a photon (gi...
- Tue Oct 15, 2019 3:16 pm
- Forum: Properties of Light
- Topic: 1A. 15 HW Problem
- Replies: 2
- Views: 85
Re: 1A. 15 HW Problem
The 102.6 nm here indicates the wavelength (λ) which you'll need to use in the c = λv equation to find the unknown frequency. Then you can plug the values in the Rydberg equation to solve for n2.
- Tue Oct 15, 2019 2:44 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Explanation of Shells
- Replies: 2
- Views: 137
Re: Explanation of Shells
An electron shell is the outside part of an atom that surrounds the atomic nucleus (almost like an outer cloud), and it is where electrons are found. The wave function for an electron in an atom is basically an atomic orbital where electrons are found, that's why there's a high probability of findin...
- Tue Oct 15, 2019 2:41 pm
- Forum: DeBroglie Equation
- Topic: Textbook Question 1B21
- Replies: 3
- Views: 210
Re: Textbook Question 1B21
You should be able to get the answer first converting mass into kilograms (=0.146 kg), and the speed which is given in miles per hour to meters per seconds (=41.1 m/s), (make sure you're using the right converting factors). Then use De Broglie's equation with the given or known values in order to so...
- Thu Oct 10, 2019 4:41 pm
- Forum: Empirical & Molecular Formulas
- Topic: Homework F9
- Replies: 4
- Views: 150
Re: Homework F9
You don't always have to multiply it by 3, it could be 2, for example. You just have to make sure you multiply by the smallest number possible to get whole integers.
- Thu Oct 10, 2019 4:33 pm
- Forum: Properties of Light
- Topic: Online Modules #28A
- Replies: 2
- Views: 127
Re: Online Modules #28A
You use the formula E (kinetic energy) = 1/2mv^2. The velocity is already given, but the mass you should use is the mass of an electron (a constant) which is 9.11 × 10^-31 kilograms.
- Thu Oct 10, 2019 3:51 pm
- Forum: Properties of Light
- Topic: Energy of light
- Replies: 4
- Views: 165
Re: Energy of light
Yes, the shorter the wavelength, the higher the energy; and the higher the frequency, the higher the energy. We get that by the inversely proportional relationship between wavelength and frequency. You can figure out through different formulas that there is a specific constant so only the wavelength...
- Thu Oct 10, 2019 3:45 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: ground/excited electron states
- Replies: 2
- Views: 137
Re: ground/excited electron states
You basically have to follow certain rules/principles to see which state they would be in. If they follow the rules/principles, they are in a ground state, if not, then they are in an excited state. For 1E.7, you are given four different examples; the rule to be followed in order to be considered in...
- Thu Oct 10, 2019 3:21 pm
- Forum: Empirical & Molecular Formulas
- Topic: Converting from grams to percentage
- Replies: 11
- Views: 7571
Re: Converting from grams to percentage
When it is already given in a percentage (of a hundred), we assume it is a 100g sample and use the numbers as they are given. But when you are given a sample of a different mass that is not 100g total, then you have to convert the individual masses by finding their mass percent composition for easie...