## Search found 105 matches

Fri Mar 13, 2020 9:39 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 3
Views: 52

### Re: Catalysts

In a chemical reaction, the transition state is defined as the highest-energy state of the system. If the molecules in the reactants collide with enough kinetic energy and this energy is higher than the transition state energy, then the reaction occurs and products form. Therefore since this is fair...
Fri Mar 13, 2020 9:30 pm
Forum: Second Order Reactions
Topic: half-life for second order runs
Replies: 2
Views: 75

### Re: half-life for second order runs

Half-life of second order reactions decrease at a much faster rate. Length of half life increases as you go down while the concentration of substrate constantly decreases, unlike zero and first order reaction.
Fri Mar 13, 2020 9:19 pm
Forum: Zero Order Reactions
Topic: Catalyst
Replies: 4
Views: 121

### Re: Catalyst

saturating the amount of substrate with catalyst does not speed up the rate of the reaction
Fri Mar 13, 2020 9:17 pm
Forum: Zero Order Reactions
Topic: half life calculations
Replies: 3
Views: 127

### Re: half life calculations

the half-life of zero order reaction decrease as the concentration decrease
the half life of a first order reaction is independent of its initial concentration.
the half-life of a second order reaction only depends on the initial concentration and the rate constant.
Fri Mar 13, 2020 8:49 pm
Forum: General Rate Laws
Topic: Temperature and kinetics
Replies: 5
Views: 103

### Re: Temperature and kinetics

As a substances absorbs heat the particles move faster so the average kinetic energy and therefore the temperature increases
Fri Mar 13, 2020 8:46 pm
Forum: General Rate Laws
Topic: Instantaneous Rate
Replies: 2
Views: 52

### Re: Instantaneous Rate

The instantaneous rate of reaction is the slope of the line (the tangent to the curve) at any time t. If you must find concentration at one specific point instead of at a range of times then draw the best tangent to the line and extend it to convenient points on the axis
Fri Mar 13, 2020 8:32 pm
Forum: General Rate Laws
Topic: Average rate vs unique rate
Replies: 4
Views: 92

### Re: Average rate vs unique rate

Average rate involves seeing how much reactant or product you make over time (average rate of consumption/formation). Unique rate involves dividing the concentration over time by the stoichiometric coefficient . Average looks at one particular time range
Fri Mar 06, 2020 10:43 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Electromotive force (emf)
Replies: 9
Views: 131

### Re: Electromotive force (emf)

Emf is given a positive value if the cell reaction is spontaneous. This implies that the electrode on the left forces electrons into the external circuit and the electrode on the right withdraws them On the other hand, Emf is given a negative value if the cell reaction is nonspontaneous. This implie...
Fri Mar 06, 2020 10:35 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Potentials
Replies: 4
Views: 71

### Re: Standard Potentials

standard potentials is the tendency for a chemical species to be reduced, and is measured in volts at standard conditions. The more positive the potential is the more likely it will be reduced.
Fri Mar 06, 2020 10:33 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E° vs E
Replies: 7
Views: 130

### Re: E° vs E

Ecell = cell potential at non-standard state conditions which can be derived from Ecell = Eocell - (RT/nF) ln Q
Eocell = standard state cell potential and can be derived from Eocell=RTlnk
Fri Mar 06, 2020 10:23 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst
Replies: 10
Views: 143

### Re: Nernst

Nernst equations is used to find Ecell under non-standard conditions. when you are given the Ecell°potential you subtarct it from RT/nF and multiply times ln Q
Fri Mar 06, 2020 10:19 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: acidic solution
Replies: 5
Views: 141

### Re: acidic solution

In acidic solutions, you have to utilize the H+ and H20 to balance
Sun Mar 01, 2020 9:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.5
Replies: 3
Views: 70

### Re: 6M.5

follow up for this question.. what would be the number of moles to obtain delta G?
Fri Feb 28, 2020 7:43 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Work and Gibbs Free Energy
Replies: 2
Views: 50

### Re: Work and Gibbs Free Energy

Gibbs free energy (ΔG) equals the work exchanged by the system with its surroundings, (-) minus the work of the pressure force. (When a system changes from initial to Final state).
Fri Feb 28, 2020 7:32 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Cell Potential
Replies: 3
Views: 48

### Re: Standard Cell Potential

In addition ,The relative reactivities of different half cells can be used to compare the direction of electron flow. A higher means there is a greater tendency for reduction to occur, while a lower one means there is a greater tendency for oxidation to occur.
Fri Feb 28, 2020 7:25 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell diagram
Replies: 3
Views: 27

### Re: cell diagram

yes always make sure the solid is on the outermost side as well as making sure it is the anode that is on the left side and cathode on the right
Fri Feb 28, 2020 7:21 am
Forum: Balancing Redox Reactions
Topic: Water and H+ Ions in Balanced Redox Reactions
Replies: 3
Views: 98

### Re: Water and H+ Ions in Balanced Redox Reactions

H20 and H+ are used to balance a redox rxn when substances are placed in an acidic solution whereas H2O and OH- is used to balanced substances in a basic solution.
Fri Feb 28, 2020 7:18 am
Forum: Balancing Redox Reactions
Topic: REDOX Agents
Replies: 9
Views: 124

### Re: REDOX Agents

A reducing agent is a substance that causes another substance to gain electrons. That said, to identify A reducing agent, it must lose electrons and is oxidized in the chemical reaction. A reducing agent is typically in one of its lower possible oxidation states, and is known as the electron donor.
Thu Feb 20, 2020 3:01 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Second law of thermodynamics
Replies: 6
Views: 158

### Re: Second law of thermodynamics

There are more ways that the energy can exist in the high entropy state than in the low entropy state. The second law in fact requires the first law to be true, otherwise entropy could spontaneously decrease in a process that destroys energy.
Thu Feb 20, 2020 2:50 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Different Types of Entropies
Replies: 6
Views: 163

### Re: Different Types of Entropies

The entropy of the surroundings will increase if energy (heat) is flowing into the surroundings from the system.If we are given the entropy changes of the system and surroundings, we can calculate total entropy change. The total entropy change is simply the sum of the system and the surroundings
Thu Feb 20, 2020 2:48 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Spontaneous
Replies: 10
Views: 250

### Re: Spontaneous

a spontaneous processes is one that occurs without the addition of external energy. A spontaneous process may take place quickly or slowly, because spontaneity is not related to kinetics or reaction rate.
Thu Feb 20, 2020 2:43 pm
Forum: Van't Hoff Equation
Topic: Significance of Van't Hoff Equation
Replies: 8
Views: 111

### Re: Significance of Van't Hoff Equation

The equation expresses the temperature dependence on the equilibrium constant K of a chemical reaction
Thu Feb 20, 2020 2:21 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Equation that relates K
Replies: 4
Views: 58

### Re: Gibbs Free Energy Equation that relates K

∆G is the change of Gibbs (free) energy for a system and ∆G° is the Gibbs energy change for a system under standard conditions (1 atm, 298K). ... Where ∆G is the difference in the energy between reactants and products. In addition ∆G is unaffected by external factors that change the kinetics of the ...
Wed Feb 12, 2020 9:06 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy
Replies: 4
Views: 81

### Re: Entropy

If you increase temperature, you increase entropy because ..
(1) More energy put into a system excites the molecules and the amount of random activity.
(2) As a gas expands in a system, entropy increases.
(3) When a solid becomes a liquid, its entropy increases.
Wed Feb 12, 2020 9:03 pm
Forum: Calculating Work of Expansion
Topic: Constant pressure in a calorimeter
Replies: 3
Views: 73

### Re: Constant pressure in a calorimeter

A constant-pressure calorimeter measures the change in enthalpy of a reaction occurring in a liquid solution. In that case, the gaseous pressure above the solution remains constant, and we say that the reaction is occurring under conditions of constant pressure.
Wed Feb 12, 2020 9:02 pm
Forum: Calculating Work of Expansion
Topic: work in reversible reaction
Replies: 4
Views: 106

### Re: work in reversible reaction

Since we are deriving a change in volume volume known as delta the d is representative of that
Wed Feb 12, 2020 9:00 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Irreversible Expansion
Replies: 7
Views: 103

### Re: Irreversible Expansion

I’m addition free expansion of a gas is an irreversible process because the temperature of a gas undergoing a free expansion is not a meaningful quantity.
Also. When talking about an isothermal free expansion of a gas, we mean that the final temperature is the same as the initial temperature.
Wed Feb 12, 2020 8:56 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: entropy at equilibrium
Replies: 3
Views: 53

### Re: entropy at equilibrium

In equilibrium, the entropy of the system cannot increase (because it is already at a maximum) and it cannot decrease (because that would violate the second law of thermodynamics).
Wed Feb 12, 2020 8:53 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: spontaneity
Replies: 34
Views: 690

### Re: spontaneity

Gibbs free energy change determines if a reaction is spontaneous under the conditions of constant pressure and constant temperature
Fri Feb 07, 2020 7:59 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Property
Replies: 5
Views: 55

### Re: State Property

Enthalpy is a state function because it depends only on two thermodynamic properties such as temperature and pressure, or temperature and entropy, or any pair of other state functions. Not on the process it took to get there
Fri Feb 07, 2020 7:52 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: First Law
Replies: 6
Views: 59

### Re: First Law

states that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy
Fri Feb 07, 2020 7:48 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reversible vs irreversible work
Replies: 7
Views: 83

### Re: reversible vs irreversible work

The work obtained in a reversible is a maximum for the process while the work obtained in a irreversible is not
Fri Feb 07, 2020 7:44 am
Forum: Phase Changes & Related Calculations
Topic: Environment
Replies: 4
Views: 82

### Re: Environment

The use alternative fuels as an energy source is intended to address concerns about fossil fuels, such as its high carbon dioxide emissions, which is an important factor in global warming.
Fri Feb 07, 2020 7:39 am
Forum: Phase Changes & Related Calculations
Topic: Enthalpy
Replies: 4
Views: 55

### Re: Enthalpy

Enthalpy encompasses the heat absorbed or evolved in a reaction
Wed Jan 29, 2020 8:25 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q vs deltaH
Replies: 6
Views: 69

### Re: q vs deltaH

q is the amount of heat transfered to the system. It is one of the two means of energy transfer during most processes studied in thermodynamics. Delta h is a thermodynamic potential, much like internal energy (E). It is essentially a measure of the potential energy of the system
Wed Jan 29, 2020 8:20 am
Forum: Phase Changes & Related Calculations
Topic: Enthalpy and Heat
Replies: 6
Views: 70

### Re: Enthalpy and Heat

Heat is the form of energy transfer from a high temperature to a lower temperature. Enthalpy is the heat transfer at a constant pressure.
Wed Jan 29, 2020 8:10 am
Forum: Phase Changes & Related Calculations
Topic: internal energy
Replies: 3
Views: 40

### Re: internal energy

in the equation ΔU=q+w w=0 and ΔU=q. The internal energy itself , NOT the change is equal to the heat of the system.
Wed Jan 29, 2020 8:02 am
Forum: Phase Changes & Related Calculations
Topic: State Functions
Replies: 9
Views: 86

### Re: State Functions

A state function is a property whose value does not depend on the path taken to reach that specific value. In contrast, functions that depend on the path from two values are call path functions. Both path and state functions are often encountered in thermodynamics.
Wed Jan 29, 2020 7:59 am
Forum: Phase Changes & Related Calculations
Topic: Phase change and temp
Replies: 8
Views: 90

### Re: Phase change and temp

During the phase change, when solid melts into liquid, its temperature remains constant as the heat energy is stored as potential energy.
Wed Jan 29, 2020 7:47 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Cpm vs. Cvm
Replies: 2
Views: 52

### Re: Cpm vs. Cvm

CV is the specific heat at constant volume, and CP is the specific heat at constant pressure. Specific heat is the heat energy required to raise the temperature of a substance (per unit mass) by one degree Celsius. The main difference between CV and CP is that the volume change is zero for a system ...
Fri Jan 24, 2020 3:10 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy and Pressure
Replies: 4
Views: 51

### Re: Enthalpy and Pressure

Most chemical reactions occur at constant pressure, so enthalpy is more often used to measure heats of reaction given off or absorbed during a chemical reaction at constant pressure. However The heat given off or absorbed when a reaction is run at constant volume is equal to the change in the intern...
Fri Jan 24, 2020 2:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q<K
Replies: 11
Views: 91

### Re: Q<K

Q<K means there are more reactants than products therefore in order to reach equilibrium more product is needed and therefore rxn will shift to the right (forward) Q>K means that there are more products than reactants therefore in order to reach equilibrium more reactant is needed and therefore rxn ...
Fri Jan 24, 2020 2:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: salt solutions
Replies: 4
Views: 70

### Re: salt solutions

A buffer solution is one which resists changes in pH when small quantities of an acid or an alkali are added to it. An acidic buffer solution is simply one which has a pH less than 7. Acidic buffer solutions are commonly made from a weak acid and one of its salts - often a sodium salt
Fri Jan 24, 2020 2:44 pm
Forum: Ideal Gases
Topic: pressure
Replies: 10
Views: 112

### Re: pressure

For a gas phase reaction, we express equilibrium constant by pressures, and when there is 1 gas it is the total pressure whereas 2 more gases are referred to as partial gas of each gas implying that the sum of them will make up the total pressure.
Fri Jan 24, 2020 2:32 pm
Forum: Ideal Gases
Topic: Homework problem 5I.11
Replies: 3
Views: 82

### Re: Homework problem 5I.11

1.20x(0.001) or 10^-3/.500L= SO2 0.50x(0.001) or 10^-3/.500L=O2 0.10x(0.001) or 10^-3/.500=SO3 set up the reaction quotient to calculate Qc (product/reactant) (0.0002)^2 _________________ = 6.94 (.001) x (.0024)^2 since this value is more than the provided Kc, more product (SO3)will form shifting to...
Wed Jan 15, 2020 5:22 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: volume's effect on K
Replies: 7
Views: 68

### Re: volume's effect on K

Volume has no effect on K because a change in volume – a decrease in volume causes an increase in pressure. To reduce the pressure, the system will try to reduce the number of gas molecules and the reaction will shift to the side with fewer gas molecules.
Wed Jan 15, 2020 5:16 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 6
Views: 45

### Re: Le Chatelier's Principle

When there is an increase in pressure, the equilibrium will shift towards the side of the reaction with fewer moles of gas. When there is a decrease in pressure, the equilibrium will shift towards the side of the reaction with more moles of gas.
Wed Jan 15, 2020 5:13 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic and exothermic reactions
Replies: 11
Views: 673

### Re: Endothermic and exothermic reactions

Endothermic processes require an input of energy to proceed and are signified by a positive change in enthalpy. Overall an increase in temp will love the forward reaction favoring the products. Exothermic processes release energy upon completion, and are signified by a negative change in enthalpy, p...
Wed Jan 15, 2020 5:02 pm
Forum: Ideal Gases
Topic: equilibrium constant
Replies: 5
Views: 55

### Re: equilibrium constant

K measures the extent to which reactants are converted to products. It refers to the reactions ability to reach a point where the concentrations of the reactant and product are unchanging with time, because the forward and backward reactions have the same rate.
Wed Jan 15, 2020 4:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acids and Base Equilibria
Replies: 4
Views: 55

### Re: Acids and Base Equilibria

Strong acids have a High KA, however a small pKA meaning it dissociate more in water. In contrast, a weak acid is less likely to ionize and release a hydrogen ion, thus resulting in a less acidic solution. The same goes for a strong base in which they will have a high KB but a small pKB.
Wed Jan 08, 2020 10:21 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure's Effect on Equilibrium
Replies: 6
Views: 101

### Re: Pressure's Effect on Equilibrium

Increasing the pressure by adding an inert gas at constant volume has no effect. This is because what matters for the equilibrium are the partial pressures of the reactants and products
Wed Jan 08, 2020 10:19 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Increasing volume
Replies: 5
Views: 389

### Re: Increasing volume

The greater density of molecules increases the number of collisions. When you decrease the pressure, molecules don't hit each other as often and the rate of reaction decreases. By decreasing the volume available to the molecules of gas, you are increasing the concentration of molecules in a specific...
Wed Jan 08, 2020 10:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Concentration
Replies: 3
Views: 50

### Re: Concentration

According to Le Chatelier's principle, adding additional reactant to a system will shift the equilibrium to the right, towards the side of the products because the frequency of successful collisions of that reactant would increase, allowing for an increase in the forward reaction, and thus the gener...
Wed Jan 08, 2020 10:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Are Both L and Aq Excluded From Equilibrium Constant Expressions?
Replies: 4
Views: 61

### Re: Are Both L and Aq Excluded From Equilibrium Constant Expressions?

Pure solids and liquids are not included in the equilibrium constant expression. This is because they do not affect the reactant amount at equilibrium in the reaction, so they are disregarded. We can't increase the concentration of a pure liquid or pure solid and hence they are omitted from the expr...
Wed Jan 08, 2020 9:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant
Replies: 8
Views: 131

### Re: Equilibrium Constant

Kc is the equilibrium constant specifically for concentrations and Kp is the equilibrium constant for partial pressures
Sun Dec 08, 2019 11:26 pm
Forum: Bronsted Acids & Bases
Topic: amphoteric
Replies: 7
Views: 247

### Re: amphoteric

Can react as a base and acid and examples include amino acids and proteins, which have amine and carboxylic acid groups, and self-ionizable compounds such as water.
Sun Dec 08, 2019 11:22 pm
Forum: Naming
Topic: "Ferrate"
Replies: 14
Views: 844

### Re: "Ferrate"

If the complex (inside brackets) is an anion the prefix -ate must be added at the end of the transition metal and iron is part of the exception that uses the beginning of its elemental symbol Fe(rrate)
Sun Dec 08, 2019 11:18 pm
Forum: Hybridization
Topic: pi bonds
Replies: 12
Views: 167

### Re: pi bonds

a pi bond is formed when two p orbitals overlap in a side-by-side fashion with the electron density concentrated above and below the plane of the nuclei of the bonding atoms.
Sun Dec 08, 2019 11:17 pm
Forum: Hybridization
Topic: double and triple bonds
Replies: 6
Views: 255

### Re: double and triple bonds

hybridization only takes into account areas of electron density not the strength of bonds (double or triple) therefore they have no effect
Sun Dec 08, 2019 11:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR and polarity
Replies: 8
Views: 214

### Re: VSEPR and polarity

Trigonal Planar, Linear, Square Planar, and Tetrahedral (if it's the same elements) will be non polar since dipoles cancel, but the rest of the shapes will be polar.
Mon Dec 02, 2019 9:01 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Anion stability
Replies: 6
Views: 95

### Re: Anion stability

The Ka value is the acid dissociation constant which determines a strong or weak acid. A higher Ka will, result in a stronger acid (more hydrogen ions)
Mon Dec 02, 2019 8:52 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids and Bases
Replies: 4
Views: 70

### Re: Conjugate Acids and Bases

A conjugate base is formed when an acid donates a proton (H+) and conjugate acid is formed when a base accepts a proton. Also if an acid is strong then conjugate base is weak and is a base is strong then conjugate acid is weak
Mon Dec 02, 2019 8:47 pm
Forum: Lewis Acids & Bases
Topic: Oxoacids
Replies: 6
Views: 88

### Re: Oxoacids

A couple examples of oxoacids can include Sulfuric acid (H2SO4), phosphoric acid (H3PO4), and nitric acid (HNO3) which suffice in completing one hydrogen, one oxygen, and one other element.
Mon Dec 02, 2019 8:43 pm
Forum: Lewis Acids & Bases
Topic: Long bonds vs Short bonds?
Replies: 9
Views: 184

### Re: Long bonds vs Short bonds?

Strong acids are defined as those that can dissociate by donating an H+ and therefore a long bond which is farther apart and weaker (easier to break) allows for this while a shorter bond doesn't considering it is stronger therefore harder to break.
Mon Dec 02, 2019 8:33 pm
Forum: Lewis Acids & Bases
Topic: Acid Strength
Replies: 4
Views: 109

### Re: Acid Strength

When the Cl-, Br-, and I- anions are placed in water they are stable and remain in their state without pulling an H away from H20. Therefore they are known to be less electronegative (weaker bond), and a weaker bond is directly associated with a stronger acid.
Fri Nov 22, 2019 11:11 am
Forum: Dipole Moments
Topic: boiling point example
Replies: 3
Views: 107

### Re: boiling point example

The greater forces of attraction will result in higher boiling and melting points because It takes more energy to separate the molecules from each other. Meanwhile a nonpolar molecule such as is symmetrical and has no positive or negative end.
Fri Nov 22, 2019 11:02 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: dipole-dipole vs induced dipole
Replies: 9
Views: 111

### Re: dipole-dipole vs induced dipole

dipole dipole occurs between polar molecules (partial negative and partial positive) while induced dipole attraction is a weak attraction that results when a polar molecule induces a dipole in an atom or in a nonpolar molecule by disturbing the arrangement of electrons in the nonpolar species. (ther...
Fri Nov 22, 2019 10:50 am
Forum: Biological Examples
Topic: Ligands
Replies: 6
Views: 511

### Re: Ligands

Ligands in biological process trigger signals and have the ability to bind to the active site of a protein through intermolecular forces (ionic bonds, hydrogen bonds, Van der Waals forces).
Fri Nov 22, 2019 10:46 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs
Replies: 13
Views: 198

### Re: Lone pairs

Only lone pairs present on the central atom are considered when determining shape an dcounting the number of areas with e- density.
Fri Nov 22, 2019 10:44 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape and Polarity
Replies: 5
Views: 91

### Re: Molecular Shape and Polarity

if all the outer atoms are the same and symmetric, the dipole moments cancel each other out and become nonpolar. However, a molecule with an unsymmetric shape will be (at least slightly) polar. Additionally lone pair or pairs of electrons on the central atom guarantee a nonuniform distribution of el...
Fri Nov 15, 2019 6:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 9
Views: 141

### Re: bond angles

Bonding pairs are slightly farther away from the central atom compared to lone pairs which utilize their higher repulsion to push the bonding pairs close together , taking up more space since they tend to be closer to the nucleus.
Fri Nov 15, 2019 6:00 pm
Forum: Dipole Moments
Topic: Hydrogen Bond
Replies: 7
Views: 163

### Re: Hydrogen Bond

A hydrogen bond is one of the stronger dipole dipole interactions due to the difference in electro negativity when bonding with fluorine oxygen or nitrogen. However in its totality is one of the weaker forces considering how easy they are to break when compared to covalent/ ionic bonds
Fri Nov 15, 2019 5:54 pm
Forum: Dipole Moments
Topic: Shape of Molecules affect boiling point?
Replies: 7
Views: 161

### Re: Shape of Molecules affect boiling point?

The idea that molecular geometry affects boiling point involves the concept that the less complex the shape the easier it will be for molecules to move freely
Fri Nov 15, 2019 5:46 pm
Forum: Dipole Moments
Topic: Can nonpolar molecules with polar bonds have dipole dipole interactions?
Replies: 4
Views: 69

### Re: Can nonpolar molecules with polar bonds have dipole dipole interactions?

Dipole dipole interaction have a significant effect only when the molecules involved are close together (touching or almost touching). Therefore since polar bond involve the attraction between the negative and positive end of an atom this causes a greater interaction.
Fri Nov 15, 2019 5:43 pm
Forum: Ionic & Covalent Bonds
Topic: Types of Covalent Bonds
Replies: 4
Views: 55

### Re: Types of Covalent Bonds

The more strongly an atom attracts the electrons in its bonds, the larger its electronegativity. Electrons in a polar covalent bond are shifted toward the more electronegative atom which is the one with the partial negative charge and results in a positive charge in the other atoms which is stronger...
Fri Nov 08, 2019 1:20 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Do higher electronegativity atoms tend to draw more electrons to them?
Replies: 6
Views: 95

### Re: Do higher electronegativity atoms tend to draw more electrons to them?

Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. Therefore a small electronegativity difference leads to a polar covalent bond and large electronegativity difference leads to an ionic bond.
Fri Nov 08, 2019 1:09 pm
Forum: Ionic & Covalent Bonds
Topic: Strength of ionic and covalent bonds
Replies: 5
Views: 81

### Re: Strength of ionic and covalent bonds

In a fully covalent bond, you only have the mixing of the orbitals, as you said. But it's not only that, you also have coulomb interactions between the nuclei, that slightly raise the energy of the molecular orbitals, which results in asymmetric energies. In a fully ionic bond you also have a coulom...
Fri Nov 08, 2019 12:52 pm
Forum: Trends in The Periodic Table
Topic: Polarizability
Replies: 4
Views: 68

### Re: Polarizability

The relationship between polarizability and the factors of electron density, atomic radii, and molecular orientation is as follows: 1. The greater the number of electrons, the less control the nuclear charge has on charge distribution, and thus the increased polarizability of the atom. 2. The greate...
Fri Nov 08, 2019 12:48 pm
Forum: Trends in The Periodic Table
Topic: electronegativity trend
Replies: 3
Views: 153

### Re: electronegativity trend

The positively charged protons in the nucleus attract the negatively charged electrons. As the number of protons in the nucleus increases, the electronegativity or attraction will increase. Therefore electronegativity increases from left to right in a row in the periodic table
Fri Nov 08, 2019 12:45 pm
Forum: Properties of Light
Topic: Frequency vs. Velocity
Replies: 8
Views: 260

### Re: Frequency vs. Velocity

velocity is measured in m/s and corresponds with c which is equal to 3.0 x 10^8 while frequency has units (hz or s^-1) and is obtained by dividing c over wavelength or by dividing energy by planck's constant (h-6.626 x 10^-34).
Sun Nov 03, 2019 2:39 pm
Forum: Ionic & Covalent Bonds
Topic: covalent character of ionic bonds
Replies: 4
Views: 55

### Re: covalent character of ionic bonds

Polarization in ionic bonds refers to the electron cloud distortion of the ions. when a cation is highly charged it will exert a strong electrostatic attraction on the e- of the anion and distort the electron cloud. If the anion has a large electron cloud it will be easily distorted. The greater the...
Sun Nov 03, 2019 2:33 pm
Forum: Ionic & Covalent Bonds
Topic: Electron Distortion
Replies: 4
Views: 59

### Re: Electron Distortion

Highly distorted electrons are described as being HIGHLY POLARIZABLE, which results in an ionic bond with more covalent characters.
Sun Nov 03, 2019 2:29 pm
Forum: Ionic & Covalent Bonds
Topic: Homework 2D #15
Replies: 5
Views: 89

### Re: Homework 2D #15

In order to determine the order of weakest bonds it is important to identify which are the larger atoms (ionic radius=decrease left to right and increase top to bottom) because the larger atoms have a larger distance therefore longer bond length which is weaker and easier to break.
Sun Nov 03, 2019 2:06 pm
Forum: Ionic & Covalent Bonds
Topic: Relationship with Polarity
Replies: 3
Views: 44

### Re: Relationship with Polarity

Non-polar bonding involves the equal sharing of electrons between identical non-metal atoms, polar bonding is the unequal sharing of electrons between two different non metal atoms. Ionic bonding is on one extreme with a complete transfer of electrons forming charged ions.
Sun Nov 03, 2019 1:52 pm
Forum: Ionic & Covalent Bonds
Topic: ionic bonds
Replies: 4
Views: 55

### Re: ionic bonds

Covalent bond normally occur between two nonmetal atoms or between a metalloid and nonmetal which can be determined by looking at the periodic table. On the other hand an ionic bond occurs between a metal and nonmetal which infers that they have completely opposite charges leading one of the atoms t...
Fri Oct 25, 2019 12:09 pm
Forum: Lewis Structures
Topic: Central Atom
Replies: 7
Views: 466

### Re: Central Atom

The central atom is usually the one with the element of lowest electronegativity, and halogens and hydrogen are usually terminal meaning the surrounding that you might have multiple of.
Fri Oct 25, 2019 12:02 pm
Forum: Lewis Structures
Topic: Bond strength
Replies: 7
Views: 107

### Re: Bond strength

Since covalent bonds involve the sharing of electrons in order to complete an octet, the atoms never have as high of an electronegativity as ionic bonds which involve the complete transfer of electrons.
Fri Oct 25, 2019 11:49 am
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 4
Views: 49

### Re: Electron Affinity

Electron affinity increases upward for the groups and from left to right across periods of a periodic table because the electrons added to energy levels become closer to the nucleus, thus a stronger attraction between the nucleus and its electrons.
Fri Oct 25, 2019 11:36 am
Forum: Ionic & Covalent Bonds
Topic: Resonance
Replies: 12
Views: 206

### Re: Resonance

Since Resonance structures lie on the fact that a molecule is able to have two or more valid electron dot structures. therefore in calculating the average (hybrid) of the structures, it will be more stable compared to a single bond.
Fri Oct 25, 2019 11:24 am
Forum: Ionic & Covalent Bonds
Topic: Calculating Number of Valence Electrons
Replies: 7
Views: 126

### Re: Calculating Number of Valence Electrons

The number of valence electrons is obtained by knowing its group number which you can identify by looking at the periodic table ad counting the rows that run down vertical. However if you want to know the general number of total electrons in all shells you look at the atomic number of the element.
Fri Oct 18, 2019 1:29 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 10
Views: 113

### Re: Nodal Planes

Nodal planes are the areas where the probability of finding electrons is zero. The two types of nodal planes are radial nodes and angular nodes.
Fri Oct 18, 2019 1:26 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin State
Replies: 6
Views: 97

### Re: Spin State

The Stern and Gerlach Experiment Electron Spin was meant to utilize silver atoms which have one unpaired electron and pass them through an atom beam that goes through a magnet and arrives at a collection plate that received an upper and lower spin from two different electrons. these spins are identi...
Fri Oct 18, 2019 1:19 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 6
Views: 93

### Re: Photoelectric Effect

If the photon energy matches that of the work function (phi) then the electron only has sufficient energy to be ejected not to be fully removed from metal.
Fri Oct 18, 2019 1:15 pm
Forum: Photoelectric Effect
Topic: Problem 1B.3
Replies: 4
Views: 68

### Re: Problem 1B.3

Electromagnetic radiation has properties of particles because is characterized as being a form of light which is absorbed in discrete units (photons)
Fri Oct 18, 2019 12:58 pm
Forum: Einstein Equation
Topic: HW 1.B.7 (b and c)
Replies: 3
Views: 84

### Re: HW 1.B.7 (b and c)

For part (b) you covert the 5.00mg into .005g Na and divide it by its molar mass of 23g/mol and multiply the answer you get by 6.02 x 10^23 atoms which should result in 1.31x10^20 atoms which you then multiply by the energy obtained in part a and you should get 44.1J. For part (c) you take the 1.00 ...
Sun Oct 13, 2019 5:31 pm
Forum: Quantum Numbers and The H-Atom
Topic: Energy quantized?
Replies: 5
Views: 80

### Re: Energy quantized?

Light is absorbed/emitted in discrete units (quanta or photons).Atoms and Molecules only absorb or emit unique frequencies that are allowed by their unique electronic structure (unlike black bodies that absorb and emit all frequencies).
Sun Oct 13, 2019 5:22 pm
Forum: Photoelectric Effect
Topic: Classic Wave in Photoelectric effect
Replies: 5
Views: 97

### Re: Classic Wave in Photoelectric effect

Since light doesn't behave like a classical wave that is (bigger wave=more intensity). The only way to obtain an emitted electron is to have the energy of a photon be greater than the energy needed to remove an electron. Light sources (short wavelength=high frequency) can eject e- even with low inte...
Sun Oct 13, 2019 5:14 pm
Forum: Photoelectric Effect
Topic: Why do photons not obey the wave equation?
Replies: 6
Views: 135

### Re: Why do photons not obey the wave equation?

Electrons have discrete energies with only certain wavelengths allowed inside one atom. Therfore the wave moel explains why electrons have quantized energy states in atoms
Sun Oct 13, 2019 4:58 pm
Forum: Properties of Electrons
Topic: Electron Excitation
Replies: 6
Views: 93

### Re: Electron Excitation

electron excitation involves the idea that electrons absorbs a particle of light (photon) and move up to a higher energy level hence the word 'excited'.
Sun Oct 13, 2019 4:48 pm
Forum: Properties of Electrons
Topic: electron energy levels
Replies: 6
Views: 70

### Re: electron energy levels

Electrons in the outermost shell have the greatest amount of potential energy because as we know potential energy is defined by energy which an object has because of its position/location, also referring to energy from net electrical charge or stored. Therefore in order to move an electron from an i...