Search found 60 matches

by CynthiaLy4F
Fri Jan 17, 2020 11:56 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quadratic
Replies: 10
Views: 30

Re: Quadratic

If you use the quadratic formula and get two positive answers, you would choose the answer where if you subtract it from any of the initial conditions given it would be result in a reasonable and nonnegative concentration or pressure.
by CynthiaLy4F
Fri Jan 17, 2020 10:09 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and Equilibrium
Replies: 9
Views: 25

Re: Solids and Equilibrium

Solids and liquids do not affect equilibrium or the equilibrium constant because solids do not have concentrations and and pure liquids usually act as a solvent in large excess so its concentration is relatively unchanged.
by CynthiaLy4F
Fri Jan 17, 2020 10:06 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Tips for Test
Replies: 16
Views: 48

Re: Tips for Test

I would recommend doing all the assigned homework problems, reading the textbook, and going over the concepts on the outlines posted on the class website.
by CynthiaLy4F
Fri Jan 17, 2020 10:00 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: increasing N2
Replies: 5
Views: 25

Re: increasing N2

When you increase the amount of N2, it will shift towards the products to make more ammonia. This will result in a decrease in the amount of H2 because the reactants are being used to make products.
by CynthiaLy4F
Fri Jan 17, 2020 9:55 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 6D.5
Replies: 1
Views: 15

Re: Textbook question 6D.5

The percent protonation should be 1.5%. I believe it was just a typo in the solutions manual.
by CynthiaLy4F
Fri Jan 10, 2020 10:35 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: predicting effects
Replies: 8
Views: 22

Re: predicting effects

Removing SO3 would result in an increase of NO because the reaction will try to make more product to minimize the effect of that change.
by CynthiaLy4F
Fri Jan 10, 2020 10:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5I.13 Part C
Replies: 2
Views: 17

Re: 5I.13 Part C

Cl2 is more thermodynamically stable relative to its atoms because it is less likely to dissociate due to its smaller equilibrium constant.
by CynthiaLy4F
Fri Jan 10, 2020 9:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating K 5I.33
Replies: 2
Views: 17

Re: Calculating K 5I.33

Yes, you would first find the moles of both the products and then calculate their concentrations and plug it into the equilibrium expression to find Kc.
by CynthiaLy4F
Fri Jan 10, 2020 9:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for K
Replies: 10
Views: 44

Re: Units for K

K is unitless because it is the activities of products over the activities of reactants. Since activities do not have units, K will not have units.
by CynthiaLy4F
Fri Jan 10, 2020 8:53 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Calculating the Equilibrium Quotient
Replies: 3
Views: 20

Re: Calculating the Equilibrium Quotient

The reaction basically measures the relative amounts of products and reactants present at any stage of the reaction. It is calculated similarly to how you would calculate for equilibrium constant where the activities of the partial pressures or molar concentrations of the products are divided by the...
by CynthiaLy4F
Sat Dec 07, 2019 12:21 am
Forum: Naming
Topic: writing formula of a given name
Replies: 5
Views: 60

Re: writing formula of a given name

I don't think writing the ligands in alphabetical order when writing the formula from the name matters.
by CynthiaLy4F
Sat Dec 07, 2019 12:10 am
Forum: Naming
Topic: Coordination Number
Replies: 3
Views: 23

Re: Coordination Number

The coordination number is determined based on the number of points ligands are attached to the central metal atom.
by CynthiaLy4F
Sat Dec 07, 2019 12:03 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: HW 9C.9
Replies: 2
Views: 18

Re: HW 9C.9

en would be a bidentate because it binds to the central atom at two points because of the lone pairs on two of its nitrogens. edta would be a hexadentate and bind to the central atom at six points.
by CynthiaLy4F
Fri Dec 06, 2019 11:51 pm
Forum: Dipole Moments
Topic: London Dispersion Forces
Replies: 4
Views: 35

Re: London Dispersion Forces

Yes, all molecules have London dispersion forces because there are always instantaneous dipole moments happening as electrons are moving around the molecule.
by CynthiaLy4F
Fri Dec 06, 2019 11:43 pm
Forum: Conjugate Acids & Bases
Topic: determining conj. acids& bases
Replies: 2
Views: 28

Re: determining conj. acids& bases

A conjugate base of an acid is the species remaining when an acid donates a proton. For example, the conjugate base of HCN would be CN-. A conjugate acid of a base is the species remaining when the acid donates a proton. For example, the conjugate acid of NH3 would be NH4+.
by CynthiaLy4F
Fri Nov 29, 2019 5:37 pm
Forum: Lewis Acids & Bases
Topic: acidic oxide/basic oxide
Replies: 2
Views: 33

Re: acidic oxide/basic oxide

Acidic oxides are molecular compounds, usually of non-metals, that form acids when they react with water. Basic oxides are oxides that react with water to form metal hydroxides.
by CynthiaLy4F
Fri Nov 29, 2019 5:14 pm
Forum: Lewis Acids & Bases
Topic: 6A.13
Replies: 7
Views: 34

Re: 6A.13

Ag+ is considered a Lewis acid because it is an electron pair acceptor. The electrons are electrostatically attracted to its positive charge.
by CynthiaLy4F
Fri Nov 29, 2019 5:09 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted vs. Lewis
Replies: 5
Views: 20

Re: Bronsted vs. Lewis

A Bronsted acid is a proton donor and a Bronsted base is a proton acceptor. A Lewis acid is an electron pair acceptor and a Lewis base is an electron pair donor.
by CynthiaLy4F
Fri Nov 29, 2019 5:02 pm
Forum: Student Social/Study Group
Topic: Midterm 2a
Replies: 4
Views: 31

Re: Midterm 2a

I think Lavelle got the equation v=E/h by just manipulating the equation E=h*v.
by CynthiaLy4F
Fri Nov 29, 2019 4:56 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: coordination number
Replies: 8
Views: 34

Re: coordination number

The coordination number is based off of the number of points at which ligands are attached to the central metal atom of the complex.
by CynthiaLy4F
Fri Nov 22, 2019 7:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AXE Format
Replies: 34
Views: 121

Re: AXE Format

When there is only one X or one E, writing just X or E would be fine.
by CynthiaLy4F
Fri Nov 22, 2019 7:41 pm
Forum: Octet Exceptions
Topic: Homework 2E.19d
Replies: 3
Views: 28

Re: Homework 2E.19d

SnCl2 is not a radical because it has an even number of electrons. Sn does not need a complete octet because bonding with two chlorine atoms and having one lone pair will give it stable formal charge of 0.
by CynthiaLy4F
Fri Nov 22, 2019 7:28 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: 9
Views: 41

Re: london forces

The molecule with the greater number of electrons will have stronger London dispersion forces.
by CynthiaLy4F
Fri Nov 22, 2019 7:24 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: 3F.5
Replies: 4
Views: 30

Re: 3F.5

Butanol has a higher melting point because it is capable of having a hydrogen bond unlike diethyl ether. This can be seen when drawing out the lewis structures.
by CynthiaLy4F
Fri Nov 22, 2019 7:18 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polarizability
Replies: 9
Views: 63

Re: polarizability

The higher the polarizability, the higher the boiling/melting points due to stronger intermolecular forces.
by CynthiaLy4F
Fri Nov 15, 2019 7:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-shaped
Replies: 3
Views: 23

Re: T-shaped

A t-shaped molecule has three bonds and 2 lone pairs. A molecule with a trigonal planar shape has only 3 bonds and a molecule with a trigonal pyramidal shape has 3 bonds and 1 lone pair.
by CynthiaLy4F
Fri Nov 15, 2019 7:47 pm
Forum: Electronegativity
Topic: Ionization Energy vs. Electronegativity
Replies: 9
Views: 44

Re: Ionization Energy vs. Electronegativity

Ionization energy is the amount of energy required to remove an electron. Electronegativity is the likelihood that an atom will gain an electron.
by CynthiaLy4F
Fri Nov 15, 2019 7:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Notation used in VSEPR
Replies: 8
Views: 42

Re: Notation used in VSEPR

I think it would be very helpful to know it because it'll help determine the different molecular shapes of molecules.
by CynthiaLy4F
Fri Nov 15, 2019 7:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E problem #13b.
Replies: 3
Views: 30

Re: 2E problem #13b.

The bond angles are not distorted because there are no lone pairs on the central atom. Therefore, the angles are still expected to be 109.5 degrees because it has a tetrahedral shape.
by CynthiaLy4F
Fri Nov 15, 2019 7:25 pm
Forum: Dipole Moments
Topic: CH
Replies: 3
Views: 32

Re: CH

No, there is no dipole moment when carbon is bonded to hydrogen because they have very similiar electronegativities.
by CynthiaLy4F
Sat Nov 09, 2019 12:26 am
Forum: Trends in The Periodic Table
Topic: atomic radius
Replies: 7
Views: 46

Re: atomic radius

Atomic radius decreases across the periodic table because the increased number of protons causes a greater effective nuclear charge that pulls electrons in, resulting in a smaller radius.
by CynthiaLy4F
Sat Nov 09, 2019 12:21 am
Forum: Quantum Numbers and The H-Atom
Topic: Quantum numbers
Replies: 12
Views: 97

Re: Quantum numbers

L is the quantum number for angular momentum. It can be any value from 0 to n-1.
by CynthiaLy4F
Sat Nov 09, 2019 12:18 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar v. Nonpolar
Replies: 11
Views: 298

Re: Polar v. Nonpolar

A molecule is polar when there is an unequal sharing of electrons between two atoms that arise due to differences in electronegativity. A molecule is nonpolar if electrons are shared equally, resulting in no dipole moment.
by CynthiaLy4F
Sat Nov 09, 2019 12:06 am
Forum: Student Social/Study Group
Topic: Dipole Moment
Replies: 5
Views: 37

Re: Dipole Moment

A dipole moment is basically what occurs when two atoms share electrons unequally. When one atom is more electronegative than the other, that atom is pulling more tightly on the shared pair of electrons. The differences in electronegativity give rise to partial positive or partial negative charges o...
by CynthiaLy4F
Fri Nov 08, 2019 11:57 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 18
Views: 107

Re: Resonance Structures

Resonance structures are other possible equivalent lewis structures that show the delocalization of electrons without changing the position of the atoms.
by CynthiaLy4F
Wed Oct 30, 2019 8:09 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 5
Views: 38

Re: Ionization Energy

The ionization energy increases from left to right because as atomic radius decreases, electrons become more attracted to the nucleus. This means that they are more tightly bound and harder to remove.
by CynthiaLy4F
Wed Oct 30, 2019 8:05 pm
Forum: Lewis Structures
Topic: 2B. 1C
Replies: 5
Views: 42

Re: 2B. 1C

It's better to put a double bond between O and N and a single bond between N and F because this structure has all the formula charges as 0, which means it is the most stable.
by CynthiaLy4F
Wed Oct 30, 2019 7:58 pm
Forum: Lewis Structures
Topic: Bonds:
Replies: 3
Views: 21

Re: Bonds:

One bond represents 2 electrons.
by CynthiaLy4F
Wed Oct 30, 2019 7:55 pm
Forum: Lewis Structures
Topic: Creating Lewis Structures
Replies: 7
Views: 53

Re: Creating Lewis Structures

The central atom would be the one that has the lowest ionization energy or is the least electronegative which in this case is Nitrogen.
by CynthiaLy4F
Wed Oct 30, 2019 7:53 pm
Forum: Octet Exceptions
Topic: Can P,S,Cl have less than 8 electrons?
Replies: 3
Views: 28

Re: Can P,S,Cl have less than 8 electrons?

They usually do not have less that 8 electrons because that would mean they are not stable. Since these elements have d-orbitals, they could have expanded octets to fit more than 8 electrons.
by CynthiaLy4F
Fri Oct 25, 2019 10:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Effective Nuclear Charge
Replies: 2
Views: 18

Re: Effective Nuclear Charge

The effective nuclear charge is the net charge an electron experiences in an atom when there are other electrons.
by CynthiaLy4F
Fri Oct 25, 2019 10:01 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 4
Views: 23

Re: Electron Affinity

Electron affinity is negative when energy is released when an electron is added and positive when energy is needed in order to add an electron.
by CynthiaLy4F
Fri Oct 25, 2019 9:54 pm
Forum: Properties of Light
Topic: Hz vs. frequency
Replies: 7
Views: 75

Re: Hz vs. frequency

Hertz is just a unit for frequency. Frequency is usually expressed in Hertz (s^-1).
by CynthiaLy4F
Fri Oct 25, 2019 9:40 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1D. 17 prob
Replies: 2
Views: 16

Re: 1D. 17 prob

Yes, that's right. The magnetic quantum number takes values of +l, l-1, and -l.
by CynthiaLy4F
Fri Oct 25, 2019 9:28 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 5
Views: 36

Re: Magnetic Quantum Number

You cannot say ml is equal to 5 because it is not the actual value. It's best to list them all out.
by CynthiaLy4F
Sat Oct 19, 2019 3:30 pm
Forum: Properties of Electrons
Topic: 1B.15
Replies: 4
Views: 39

Re: 1B.15

You could use De Broglie's equation.
by CynthiaLy4F
Sat Oct 19, 2019 3:24 pm
Forum: Properties of Light
Topic: Baler v. Lyman Series
Replies: 10
Views: 64

Re: Baler v. Lyman Series

The Balmer series corresponds to the visible light region of the spectrum and the Lyman Series corresponds to the UV region of the spectrum. In the Balmer series, the electrons come to rest at the energy level n=2 and in the Lyman series, the electrons come to rest at n=1.
by CynthiaLy4F
Sat Oct 19, 2019 3:14 pm
Forum: DeBroglie Equation
Topic: 1B.15 a
Replies: 4
Views: 26

Re: 1B.15 a

The mass would be that of an electron which is 9.1095*10^-31 kg.
by CynthiaLy4F
Sat Oct 19, 2019 2:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Paired Electrons
Replies: 5
Views: 36

Re: Paired Electrons

When electrons are paired, they occupy the same orbital with opposite spin. There can be no more than 2 electrons in an orbital based on the Pauli Exclusion Principle. When electrons are parallel, they occupy different orbitals with the same spin. This occurs because there is electron repulsion betw...
by CynthiaLy4F
Sat Oct 19, 2019 2:45 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Inner e- and Outer e-
Replies: 14
Views: 83

Re: Inner e- and Outer e-

The outer electrons feel a reduced electrostatic attraction because the inner electrons shield the outer electrons from the positive nucleus.
by CynthiaLy4F
Fri Oct 11, 2019 9:10 pm
Forum: Einstein Equation
Topic: E=hv
Replies: 8
Views: 68

Re: E=hv

The h represents Planck's constant, which is 6.626*10^-34 J*s.
by CynthiaLy4F
Fri Oct 11, 2019 9:00 pm
Forum: Limiting Reactant Calculations
Topic: percent yield
Replies: 10
Views: 145

Re: percent yield

You don't have to worry about finding the percent yield unless the question specifically asks for you to find it.
by CynthiaLy4F
Fri Oct 11, 2019 8:53 pm
Forum: Empirical & Molecular Formulas
Topic: empirical = molecular?
Replies: 15
Views: 165

Re: empirical = molecular?

If the molar mass is the same for the empirical and molecular formula, then the chemical formula would just be the same for both.
by CynthiaLy4F
Fri Oct 11, 2019 8:47 pm
Forum: Significant Figures
Topic: Sig Figs
Replies: 5
Views: 72

Re: Sig Figs

It's best to just use the correct number of sig figs in your final answer to reduce any small errors from rounding in the middle of your calculations.
by CynthiaLy4F
Fri Oct 11, 2019 8:42 pm
Forum: Limiting Reactant Calculations
Topic: Exercise M.1
Replies: 3
Views: 64

Re: Exercise M.1

First you divide you're 35.0 g of NH3 by the molar mass of NH3 and then use mole ratios to find the number of moles of N2H2. Then multiply the number of moles of N2H4 by its molar mass and you will get the theoretical yield of N2H4. Divide the actual yield of N2H4 by the theoretical yield and multip...
by CynthiaLy4F
Wed Oct 02, 2019 9:08 pm
Forum: SI Units, Unit Conversions
Topic: Sig figs
Replies: 18
Views: 178

Re: Sig figs

No, the number of sig figs can vary because it is based on the least amount of sig figs present in the problem. However, any conversion factors do not count when determining the number of sig figs.
by CynthiaLy4F
Tue Oct 01, 2019 3:50 pm
Forum: Limiting Reactant Calculations
Topic: Another question on E9 but now on part b
Replies: 2
Views: 23

Re: Another question on E9 but now on part b

Yes, you would find the moles of the compound first by dividing the number of grams given by the molar mass of magnesium sulfate heptahydrate and then multiply it by Avogadro's constant (6.022 X 10^23) to get the number of formula units of the compound.
by CynthiaLy4F
Tue Oct 01, 2019 1:51 pm
Forum: Significant Figures
Topic: Sig Fig Decimal
Replies: 10
Views: 87

Re: Sig Fig Decimal

They both have three sig figs but I think 114 would be the better answer just because the extra decimal after 114 seems unnecessary.
by CynthiaLy4F
Tue Oct 01, 2019 1:46 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs Covalent
Replies: 29
Views: 379

Re: Ionic vs Covalent

Ionic bonds are stronger than covalent bonds, because there is a stronger attraction between ions that have opposite charges, which is why it takes a lot of energy to separate them. Covalent bonds are bonds that involve the sharing of electron pairs between atoms.
by CynthiaLy4F
Tue Oct 01, 2019 10:24 am
Forum: SI Units, Unit Conversions
Topic: Unit Conversions
Replies: 11
Views: 117

Re: Unit Conversions

To convert from atoms to moles, you would divide the number of atoms by 6.022 x 10^23 (Avogadro's constant) to get the number of moles. It would be helpful to memorize that the number of objects (ions, atoms, or molecules) = amount of moles x Avogadro's constant and rearrange the equation to solve f...

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