Search found 60 matches

by Miriam Villarreal 1J
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: 24

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.
by Miriam Villarreal 1J
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: 10

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.
by Miriam Villarreal 1J
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: 33

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...
by Miriam Villarreal 1J
Wed Jan 15, 2020 5:02 pm
Forum: Ideal Gases
Topic: equilibrium constant
Replies: 5
Views: 26

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.
by Miriam Villarreal 1J
Wed Jan 15, 2020 4:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acids and Base Equilibria
Replies: 4
Views: 34

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.
by Miriam Villarreal 1J
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: 56

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
by Miriam Villarreal 1J
Wed Jan 08, 2020 10:19 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Increasing volume
Replies: 5
Views: 212

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...
by Miriam Villarreal 1J
Wed Jan 08, 2020 10:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Concentration
Replies: 3
Views: 25

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...
by Miriam Villarreal 1J
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: 31

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...
by Miriam Villarreal 1J
Wed Jan 08, 2020 9:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant
Replies: 8
Views: 57

Re: Equilibrium Constant

Kc is the equilibrium constant specifically for concentrations and Kp is the equilibrium constant for partial pressures
by Miriam Villarreal 1J
Sun Dec 08, 2019 11:26 pm
Forum: Bronsted Acids & Bases
Topic: amphoteric
Replies: 7
Views: 71

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.
by Miriam Villarreal 1J
Sun Dec 08, 2019 11:22 pm
Forum: Naming
Topic: "Ferrate"
Replies: 14
Views: 126

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)
by Miriam Villarreal 1J
Sun Dec 08, 2019 11:18 pm
Forum: Hybridization
Topic: pi bonds
Replies: 3
Views: 36

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.
by Miriam Villarreal 1J
Sun Dec 08, 2019 11:17 pm
Forum: Hybridization
Topic: double and triple bonds
Replies: 6
Views: 40

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
by Miriam Villarreal 1J
Sun Dec 08, 2019 11:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR and polarity
Replies: 8
Views: 59

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.
by Miriam Villarreal 1J
Mon Dec 02, 2019 9:01 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Anion stability
Replies: 6
Views: 52

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)
by Miriam Villarreal 1J
Mon Dec 02, 2019 8:52 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids and Bases
Replies: 4
Views: 31

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
by Miriam Villarreal 1J
Mon Dec 02, 2019 8:47 pm
Forum: Lewis Acids & Bases
Topic: Oxoacids
Replies: 6
Views: 38

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.
by Miriam Villarreal 1J
Mon Dec 02, 2019 8:43 pm
Forum: Lewis Acids & Bases
Topic: Long bonds vs Short bonds?
Replies: 9
Views: 56

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.
by Miriam Villarreal 1J
Mon Dec 02, 2019 8:33 pm
Forum: Lewis Acids & Bases
Topic: Acid Strength
Replies: 4
Views: 31

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.
by Miriam Villarreal 1J
Fri Nov 22, 2019 11:11 am
Forum: Dipole Moments
Topic: boiling point example
Replies: 3
Views: 40

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.
by Miriam Villarreal 1J
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: 59

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...
by Miriam Villarreal 1J
Fri Nov 22, 2019 10:50 am
Forum: Biological Examples
Topic: Ligands
Replies: 6
Views: 311

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).
by Miriam Villarreal 1J
Fri Nov 22, 2019 10:46 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs
Replies: 13
Views: 56

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.
by Miriam Villarreal 1J
Fri Nov 22, 2019 10:44 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape and Polarity
Replies: 5
Views: 32

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...
by Miriam Villarreal 1J
Fri Nov 15, 2019 6:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 9
Views: 40

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.
by Miriam Villarreal 1J
Fri Nov 15, 2019 6:00 pm
Forum: Dipole Moments
Topic: Hydrogen Bond
Replies: 7
Views: 46

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
by Miriam Villarreal 1J
Fri Nov 15, 2019 5:54 pm
Forum: Dipole Moments
Topic: Shape of Molecules affect boiling point?
Replies: 7
Views: 30

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
by Miriam Villarreal 1J
Fri Nov 15, 2019 5:46 pm
Forum: Dipole Moments
Topic: Can nonpolar molecules with polar bonds have dipole dipole interactions?
Replies: 4
Views: 36

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.
by Miriam Villarreal 1J
Fri Nov 15, 2019 5:43 pm
Forum: Ionic & Covalent Bonds
Topic: Types of Covalent Bonds
Replies: 4
Views: 26

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...
by Miriam Villarreal 1J
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: 25

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.
by Miriam Villarreal 1J
Fri Nov 08, 2019 1:09 pm
Forum: Ionic & Covalent Bonds
Topic: Strength of ionic and covalent bonds
Replies: 5
Views: 24

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...
by Miriam Villarreal 1J
Fri Nov 08, 2019 12:52 pm
Forum: Trends in The Periodic Table
Topic: Polarizability
Replies: 4
Views: 36

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...
by Miriam Villarreal 1J
Fri Nov 08, 2019 12:48 pm
Forum: Trends in The Periodic Table
Topic: electronegativity trend
Replies: 3
Views: 30

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
by Miriam Villarreal 1J
Fri Nov 08, 2019 12:45 pm
Forum: Properties of Light
Topic: Frequency vs. Velocity
Replies: 8
Views: 81

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).
by Miriam Villarreal 1J
Sun Nov 03, 2019 2:39 pm
Forum: Ionic & Covalent Bonds
Topic: covalent character of ionic bonds
Replies: 4
Views: 31

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...
by Miriam Villarreal 1J
Sun Nov 03, 2019 2:33 pm
Forum: Ionic & Covalent Bonds
Topic: Electron Distortion
Replies: 4
Views: 29

Re: Electron Distortion

Highly distorted electrons are described as being HIGHLY POLARIZABLE, which results in an ionic bond with more covalent characters.
by Miriam Villarreal 1J
Sun Nov 03, 2019 2:29 pm
Forum: Ionic & Covalent Bonds
Topic: Homework 2D #15
Replies: 5
Views: 46

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.
by Miriam Villarreal 1J
Sun Nov 03, 2019 2:06 pm
Forum: Ionic & Covalent Bonds
Topic: Relationship with Polarity
Replies: 3
Views: 28

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.
by Miriam Villarreal 1J
Sun Nov 03, 2019 1:52 pm
Forum: Ionic & Covalent Bonds
Topic: ionic bonds
Replies: 4
Views: 36

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...
by Miriam Villarreal 1J
Fri Oct 25, 2019 12:09 pm
Forum: Lewis Structures
Topic: Central Atom
Replies: 7
Views: 281

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.
by Miriam Villarreal 1J
Fri Oct 25, 2019 12:02 pm
Forum: Lewis Structures
Topic: Bond strength
Replies: 7
Views: 45

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.
by Miriam Villarreal 1J
Fri Oct 25, 2019 11:49 am
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 4
Views: 29

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.
by Miriam Villarreal 1J
Fri Oct 25, 2019 11:36 am
Forum: Ionic & Covalent Bonds
Topic: Resonance
Replies: 12
Views: 93

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.
by Miriam Villarreal 1J
Fri Oct 25, 2019 11:24 am
Forum: Ionic & Covalent Bonds
Topic: Calculating Number of Valence Electrons
Replies: 7
Views: 53

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.
by Miriam Villarreal 1J
Fri Oct 18, 2019 1:29 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 10
Views: 53

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.
by Miriam Villarreal 1J
Fri Oct 18, 2019 1:26 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin State
Replies: 6
Views: 51

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...
by Miriam Villarreal 1J
Fri Oct 18, 2019 1:19 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 6
Views: 33

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.
by Miriam Villarreal 1J
Fri Oct 18, 2019 1:15 pm
Forum: Photoelectric Effect
Topic: Problem 1B.3
Replies: 4
Views: 33

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)
by Miriam Villarreal 1J
Fri Oct 18, 2019 12:58 pm
Forum: Einstein Equation
Topic: HW 1.B.7 (b and c)
Replies: 3
Views: 31

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 ...
by Miriam Villarreal 1J
Sun Oct 13, 2019 5:31 pm
Forum: Quantum Numbers and The H-Atom
Topic: Energy quantized?
Replies: 5
Views: 42

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).
by Miriam Villarreal 1J
Sun Oct 13, 2019 5:22 pm
Forum: Photoelectric Effect
Topic: Classic Wave in Photoelectric effect
Replies: 5
Views: 44

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...
by Miriam Villarreal 1J
Sun Oct 13, 2019 5:14 pm
Forum: Photoelectric Effect
Topic: Why do photons not obey the wave equation?
Replies: 6
Views: 86

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
by Miriam Villarreal 1J
Sun Oct 13, 2019 4:58 pm
Forum: Properties of Electrons
Topic: Electron Excitation
Replies: 6
Views: 29

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'.
by Miriam Villarreal 1J
Sun Oct 13, 2019 4:48 pm
Forum: Properties of Electrons
Topic: electron energy levels
Replies: 6
Views: 31

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...
by Miriam Villarreal 1J
Sun Oct 06, 2019 6:11 pm
Forum: Balancing Chemical Reactions
Topic: Question H17
Replies: 1
Views: 23

Question H17

Steps into solving H17.
Write a balanced equation for the complete combustion (reaction with oxygen gas) of liquid heptane , C7H16 a component typical of the hydrocarbons in gasoline to carbon dioxide gas and water vapor
by Miriam Villarreal 1J
Sun Oct 06, 2019 6:05 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question G7
Replies: 2
Views: 26

Re: Question G7

1. Find out how much grams of KNO3 are in the 510 gram sample 2. Divide the 5.45% by 100 to get .0545 3. Multiply .0545g (percent of KNO3) by 510g to determine the amount of KNO3in solution which equals 27.8g 4. Take the total amount of 510g and subtract by 27.8 to find out how much of the aqueous s...
by Miriam Villarreal 1J
Sun Oct 06, 2019 6:02 pm
Forum: Molarity, Solutions, Dilutions
Topic: G. 13
Replies: 5
Views: 50

Re: G. 13

Dilution Formula: M1V1=M2V2
Therefore, (0.20NH4No3)(1.0L)=M2(4.0L) - you add the 3.0L and 1.0L
=.05 mol NH4NO3
by Miriam Villarreal 1J
Sun Oct 06, 2019 5:59 pm
Forum: Molarity, Solutions, Dilutions
Topic: G5
Replies: 6
Views: 110

Re: G5

-1st step involves calculating the moles of Na2CO3

2.111gNa2CO3
_____________________ = .01992 mol NaCo3
105.991 g/mol Na2CO3

-2nd step
.01992 mol/.250L=.0769 mol/L or about .080mol/L

(a) Convert mmol to mol .002015 mol Na/0.16 mol/L = 0.013 L Na x 1000ml = 13 mL Na is needed to transfer
by Miriam Villarreal 1J
Sun Oct 06, 2019 5:44 pm
Forum: Molarity, Solutions, Dilutions
Topic: Volumetric Analysis
Replies: 2
Views: 34

Volumetric Analysis

L37) Part b: How many milliliters of 0.20M NaOH(aq) could be neutralized by 100.mL of the diluted solution?

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