Search found 49 matches

by Rana YT 2L
Sun Mar 18, 2018 12:14 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Collision Theory
Replies: 5
Views: 244

Re: Collision Theory

collisions are more likely when the reactants meet at the right orientation and with enough energy. increasing the temperature helps satisfy the need for more molecules of reactant colliding with enough energy
by Rana YT 2L
Sun Mar 18, 2018 12:12 am
Forum: *Enzyme Kinetics
Topic: Enzymes
Replies: 8
Views: 582

Re: Enzymes

the most basic understanding is that enzymes make the reaction faster by providing a different pathway in which the activation energy is lower
by Rana YT 2L
Sun Mar 18, 2018 12:10 am
Forum: *Enzyme Kinetics
Topic: Catalyst and equilibrium constant
Replies: 3
Views: 635

Re: Catalyst and equilibrium constant

the equilibrium constant does not change but the k that is the rate constant does change
by Rana YT 2L
Mon Mar 05, 2018 2:10 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Bimolecular Reactions [ENDORSED]
Replies: 2
Views: 122

Re: Bimolecular Reactions [ENDORSED]

bimolecular refers to any two molecules interacting

whether it be A + A or A+B
by Rana YT 2L
Mon Mar 05, 2018 2:09 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Which Step is Slower?
Replies: 8
Views: 230

Re: Which Step is Slower?

The slow step is also the step with the largest activation energy
by Rana YT 2L
Mon Mar 05, 2018 2:08 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Assuming Elementary Rxn [ENDORSED]
Replies: 2
Views: 134

Re: Assuming Elementary Rxn [ENDORSED]

We didn't just assume that it was the elementary step. He gave us the rate law initially and because the rate law is solely dependent on the slow step, you can determine which of the elementary steps is the slow step by matching that steps rate law to the rate law that was given initially
by Rana YT 2L
Sun Feb 18, 2018 8:28 pm
Forum: Balancing Redox Reactions
Topic: Balancing
Replies: 3
Views: 209

Re: Balancing

yes you do in both acidic and basic solutions
by Rana YT 2L
Sun Feb 18, 2018 8:25 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: cell potential equations
Replies: 3
Views: 319

Re: cell potential equations

depending on your calculator, you might have to put in log with a base of 10 explicitly since some calculators imply that base while others dont
by Rana YT 2L
Sun Feb 18, 2018 8:22 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration Cells
Replies: 3
Views: 336

Re: Concentration Cells

You need the difference in concentration so that in order for the reaction to be spontaneous, the electrons that are lost in the anode must move to the cathode. Therefore, the reactants must have a larger concentration so that the reaction in the anode takes place so that the electrons move from the...
by Rana YT 2L
Sun Feb 18, 2018 8:20 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration
Replies: 3
Views: 180

Re: Concentration

the higher the concentration of products, the higher the value of Q, the more negative the value of Ecell, and therefore the reaction it is un-spontaneous the higher the concentration of reactants, the lower the value of Q, the more positive the value of Ecell, and therefore the reaction is spontane...
by Rana YT 2L
Sun Feb 18, 2018 8:18 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Cell Potentials
Replies: 5
Views: 161

Re: Standard Cell Potentials

yes it is because potentials are intensive properties
by Rana YT 2L
Sun Feb 18, 2018 8:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells 14.3
Replies: 2
Views: 109

Re: Galvanic Cells 14.3

If the reaction takes place in a cell that performs electrical work, then the heat released is diminished by the amount of electrical work done.
by Rana YT 2L
Sun Feb 18, 2018 8:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Platinum electrodes
Replies: 4
Views: 166

Re: Platinum electrodes

platinum electrodes are used when there are no metal solids or only one metal solid. a platinum electrode is not required when BOTH the anode and cathode reactions contain solid metals
by Rana YT 2L
Sun Feb 18, 2018 8:12 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: inert metals
Replies: 1
Views: 92

inert metals

Is there a specific inert metal that must be used in certain reactions or can we generalize it and use any inert metal?
by Rana YT 2L
Sun Feb 18, 2018 8:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 3
Views: 148

Re: Cell Diagrams

They will be written in the way the reaction takes place so the direction does matter
by Rana YT 2L
Mon Feb 05, 2018 11:43 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.35?
Replies: 2
Views: 137

Re: 9.35?

there is an error and C should have the greatest entropy because it has both vibrational and rotational energy
by Rana YT 2L
Mon Feb 05, 2018 11:40 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.31d
Replies: 1
Views: 54

Re: 9.31d

it's not always the same, it depends on the different energies like rotational, etc.
by Rana YT 2L
Mon Feb 05, 2018 11:35 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.85
Replies: 2
Views: 129

Re: 9.85

a) a positive enthalpy would result in the dissolving to be unfavorable because a positive enthalpy would result in a positive ∆G value and a negative enthalpy would result in the dissolving to be favorable because a negative enthalpy would result in negative ∆G.
by Rana YT 2L
Tue Jan 30, 2018 9:44 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Perfect Crystal in terms of Entropy
Replies: 2
Views: 80

Re: Perfect Crystal in terms of Entropy

in addition, Dr. Lavelle mentioned in lecture that an entropy=0 can only occur when the temperature is at 0 K.
by Rana YT 2L
Tue Jan 30, 2018 9:42 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: heat capacity and entropy
Replies: 2
Views: 88

Re: heat capacity and entropy

the entropy increases because a higher heat capacity means that more energy will be needed to increase that substances temperature by 1 Celsius. That extra energy needed is transferred to the substances atoms and molecules and increase their energy. This increase in energy can result in an increase ...
by Rana YT 2L
Tue Jan 30, 2018 9:38 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Cv vs. R
Replies: 1
Views: 115

Cv vs. R

I was looking through the solutions manual and noticed that it uses Cv and R interchangeably for some problems involving ideal gases. Why can is it that this can happen?
by Rana YT 2L
Mon Jan 22, 2018 11:13 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: self test 8.7B
Replies: 2
Views: 135

Re: self test 8.7B

the answers for the B portions of the self test questions can be found in the back of the book under answers> self-test B
by Rana YT 2L
Mon Jan 22, 2018 11:10 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Volume vs Constant Pressure
Replies: 2
Views: 100

Re: Constant Volume vs Constant Pressure

to add onto the previous post,
the actual q equations are the same, you only need to change the value of the specific heat to reflect that of a system under constant pressure or constant volume
q=nCp∆T
or
q=nCv∆T
by Rana YT 2L
Mon Jan 22, 2018 11:06 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.99 Negative Specific Heat Capacity
Replies: 3
Views: 156

Re: 8.99 Negative Specific Heat Capacity

If you put your final answer in Celcius, it is possible that hte temperature could be negative, indicating that is lost heat
by Rana YT 2L
Tue Jan 16, 2018 8:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Problem 8.65
Replies: 2
Views: 121

Re: Problem 8.65

that is the reaction you want because that forms one mole of N2O5 and the equation asks for the enthalpy of formation for N2O5 and that refers to the amount of energy needed for one mole of N2O5 when it is formed by elements in their natural form. the purpose of the reaction you mentioned is to allo...
by Rana YT 2L
Tue Jan 16, 2018 8:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Chapter 8 8.57
Replies: 1
Views: 114

Re: Chapter 8 8.57

you would write out the combustion analyses for each molecule and manipulate the equations and enthalpy values in a way so that you end up with the equation provided when all 3 combustion reactions are added together. you would write the combustion reaction for H2 without it forming CO2. yes, the eq...
by Rana YT 2L
Tue Jan 16, 2018 8:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Heat Capacities
Replies: 6
Views: 136

Re: Heat Capacities

the molar heat capacity is the amount of heat needed to raise the temperature of 1 mole of a substance by 1 degree Celsius or 1 kelvin.
the specific heat capacity is the amount of heat needed to raise the temperature of 1 gram of a substance by 1 degree celsius or 1 kelvin
by Rana YT 2L
Tue Jan 16, 2018 7:56 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.19
Replies: 2
Views: 156

Re: 8.19

the q values for the water and the copper are added in the solution manual because no heat is technically being lost. Instead, heat is simply being transferred into the kettle and then into the water. Because of this, there is no loss in heat in either kettle nor the copper, meaning that no negative...
by Rana YT 2L
Wed Jan 10, 2018 9:25 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 8
Views: 370

Re: Hess's Law

They will always cancel each other out because hess’s Law is just a representation of steps that give the final output. Therefore, if some didn’t cancel out, there would be a different number of products
by Rana YT 2L
Wed Jan 10, 2018 9:21 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy of Freezing
Replies: 4
Views: 226

Re: Enthalpy of Freezing

That is correct but the negative is arbitrary since it depends on the direction of the phase change
by Rana YT 2L
Wed Jan 10, 2018 9:20 pm
Forum: Phase Changes & Related Calculations
Topic: chapter 8
Replies: 6
Views: 268

Re: chapter 8

Yes he is started with the second half which is section 10 to section 20
by Rana YT 2L
Wed Nov 29, 2017 1:30 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Concept Question
Replies: 3
Views: 219

Re: Concept Question

it's all based on the ratios so in order to increase the yield of ammonia, you need to decrease ammonia (take some out) because then the ratio will heavily favor the reactants. for example if at equilibrium the ratio of reactants to products is 2:2 so when you remove the ammonia, the ratio becomes 2...
by Rana YT 2L
Wed Nov 29, 2017 1:27 am
Forum: Ideal Gases
Topic: 11.7 Part a
Replies: 3
Views: 275

Re: 11.7 Part a

If you look at the question, it says that the flasks show dissassociation over time. Therefore, you must pick the flask that has no more change by looking at the next flask. You see this occur at flask 3 as in flask 4 there is no change. However in addition to this you have to make sure that the co...
by Rana YT 2L
Wed Nov 29, 2017 1:26 am
Forum: Ideal Gases
Topic: Units for the formula
Replies: 4
Views: 386

Re: Units for the formula

you should note that the values of R with both the pressure in atm and bar are given values on the constants sheet
by Rana YT 2L
Wed Nov 29, 2017 1:23 am
Forum: Ideal Gases
Topic: 11.7 Part C
Replies: 2
Views: 217

Re: 11.7 Part C

they use that equation because in order to determine partial pressures, you need to look at the number of moles of each gas atom or molecule within the closed volume since the number of moles of gas will determine how the reaction changes as it approaches equilibrium or how the reaction will react i...
by Rana YT 2L
Wed Nov 29, 2017 1:21 am
Forum: Ideal Gases
Topic: Pascal vs Atmosphere
Replies: 3
Views: 341

Re: Pascal vs Atmosphere

Lavelle does prefer atm however you need to double check what the original units are for the partial pressure given and match those units. if no units are given but an R (gas constant) value is given, double check to see whether that value of R represents the pressure in atm or bar.
by Rana YT 2L
Wed Nov 29, 2017 1:19 am
Forum: Hybridization
Topic: general hybridization
Replies: 2
Views: 156

Re: general hybridization

all you need to do is count the areas of electron density and add them. for example, 2 areas of high electron density would be sp, 3 would be sp^2, 4 would be sp^3, 5 would be sp^3d, and 6 would be sp^3d^2
by Rana YT 2L
Wed Nov 29, 2017 1:16 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Dipole moments
Replies: 2
Views: 184

Re: Dipole moments

put succinctly, you need to look at the geometry of the bond and the electronegativity of the atoms within the compound in order to determine whether dipole moments do or do not cancel out
by Rana YT 2L
Thu Nov 09, 2017 11:55 am
Forum: Dipole Moments
Topic: Polarity
Replies: 5
Views: 481

Re: Polarity

In addition to the posts above, if you would like to get a general sense as to whether a molecule is polar or not, you can also compare the relative electronegativity of each of the atoms that occupy it. If the difference in their electronegativity is great (based on periodic trends), then you can a...
by Rana YT 2L
Thu Nov 09, 2017 11:52 am
Forum: Dipole Moments
Topic: Finding Dipole Moments
Replies: 3
Views: 417

Re: Finding Dipole Moments

To continue on with the previous post, when looking at the most electronegative element, however, you have to look at it in comparison to the other atom. This means that you need to see if there is a significant difference in electronegativity between the two elements
by Rana YT 2L
Sun Nov 05, 2017 11:57 pm
Forum: Lewis Structures
Topic: Problem 3.59 Part A
Replies: 4
Views: 211

Re: Problem 3.59 Part A

The ion is able to exist only because the extra electron becomes part of another bond
by Rana YT 2L
Sun Nov 05, 2017 11:56 pm
Forum: Lewis Structures
Topic: 3.25 part d
Replies: 2
Views: 138

Re: 3.25 part d

Hydrogen can act as a cation because of its low ionization energy
by Rana YT 2L
Wed Oct 25, 2017 11:02 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Energy level for n=3 and n=4?
Replies: 3
Views: 283

Re: Energy level for n=3 and n=4?

The 3d sub shell is higher than 4s when the 4s subshell is full but the 3d subshell is completely empty. However, the minute that 3d gains an electron, the 4s subshell becomes the higher energy subshell.
by Rana YT 2L
Wed Oct 25, 2017 10:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: HW Question 2.43
Replies: 4
Views: 223

Re: HW Question 2.43

The answer is correct because when you put [Xe] you are saying that the electron configuration already consists of the electron configuration for Xe
by Rana YT 2L
Thu Oct 19, 2017 11:36 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 1.6b
Replies: 2
Views: 176

Re: 1.6b

make sure that when you're calculating it using the bohr relationship that you convert the values into kilograms and m/s before you calculate the wavelength.
by Rana YT 2L
Thu Oct 19, 2017 11:33 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Uncertainty Equation
Replies: 7
Views: 378

Re: Heisenberg Uncertainty Equation

You can expect the uncertainty to be greater for an electron because an electron has a smaller mass, and since mass is inversely proportional to velocity, would have a greater speed and momentum in comparison to the marble
by Rana YT 2L
Thu Oct 05, 2017 10:48 pm
Forum: Significant Figures
Topic: E29 (d) Significant Figures
Replies: 3
Views: 330

Re: E29 (d) Significant Figures

The number of sig figs only depends on the original number of sig figs in the original values given. So you simply have to look back at the original values, but don't forget to take into consideration the fact that the rules for addition and subtraction can affect that value.
by Rana YT 2L
Thu Oct 05, 2017 10:43 pm
Forum: Limiting Reactant Calculations
Topic: Reactant vs. Reagent [ENDORSED]
Replies: 23
Views: 9451

Re: Reactant vs. Reagent [ENDORSED]

While they may have different definitions, when they are used in a question, the two terms can essentially be used interchangeably.

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