Search found 149 matches

by jisulee1C
Sat Nov 30, 2019 11:41 pm
Forum: Student Social/Study Group
Topic: Preparing for the final
Replies: 25
Views: 243

Re: Preparing for the final

The learning objectives are on the class website under learning outcomes.
by jisulee1C
Sat Nov 30, 2019 11:41 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 22

Re: Polydentate

Polydentate ligands range in the number of atoms used to bond to a central metal atom or ion. For example, Bidentate ligands will have two donor atoms which allow them to bind a central metal atom or ion at two points (ex. ethylenediamine). To determine the dentate the number of lone pairs that can ...
by jisulee1C
Tue Nov 19, 2019 11:40 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear Shape
Replies: 6
Views: 47

Re: Linear Shape

Even though shape of linear is non polar if there are different atoms on each side of the central atom then even if the shape is non polar there will be unequal dipoles and therefore the molecule can be polar an example might be HCN.
by jisulee1C
Tue Nov 19, 2019 11:32 am
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Gas Phase Question
Replies: 5
Views: 136

Re: Gas Phase Question

Neon has less London dispersion forces than Argon. Because there are less dispersion forces holding the Neon molecules together it is easier to break and the bonds are therefore weaker. Because the bonds are weaker it is more likely to be a gas (gas molecules are able to move around more freely than...
by jisulee1C
Tue Nov 19, 2019 11:28 am
Forum: Determining Molecular Shape (VSEPR)
Topic: polarity
Replies: 5
Views: 44

Re: polarity

Even though a tetrahedral shape is non polar because there are different atoms bonded on each side of the central atom there will be dipoles. And because the dipoles are unequal they will not cancel each other out and therefore it will be a polar molecule.
by jisulee1C
Mon Nov 18, 2019 9:58 pm
Forum: Hybridization
Topic: Stability of bonds
Replies: 3
Views: 32

Re: Stability of bonds

A sigma bond results in the direct overlapping while a pi bond results from overlap sideways. Therefore a sigma bond is stronger than a pi bond.
by jisulee1C
Mon Nov 18, 2019 9:57 pm
Forum: Ionic & Covalent Bonds
Topic: Is ionic or covalent stronger?
Replies: 4
Views: 88

Re: Is ionic or covalent stronger?

It depends on the situation. In biology you hear that covalent bonds are stronger because you are usually comparing covalent bonds with ionic bonds in water. When ionic bonds are in water they are much weaker. However, in chemistry you usually say that ionic bonds are stronger because they are harde...
by jisulee1C
Mon Nov 18, 2019 9:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: CS2
Replies: 1
Views: 25

Re: CS2

yes. because the CS2 shape (symmetrical) is linear the dipoles cancel each other out and therefore the molecule is non polar.
by jisulee1C
Mon Nov 18, 2019 9:54 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: Determining the greater boiling point
Replies: 4
Views: 47

Re: Determining the greater boiling point

It depends on what you are comparing. But the most important factors should be the IMF (intermolecular forces) that are broken when the molecule is boiled. For example if comparing anything with a hydrogen bond (ex. HF) to another molecules say with only London dispersion forces (ex. HCl) then the m...
by jisulee1C
Mon Nov 18, 2019 9:46 pm
Forum: Hybridization
Topic: Test 2
Replies: 6
Views: 70

Re: Test 2

hybridization will not be on test 2. test 2 will cover only up to sigma and pi bonds.
by jisulee1C
Mon Nov 18, 2019 9:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs & Polarity
Replies: 3
Views: 36

Re: Lone Pairs & Polarity

Polarity depends on the molecule. If the molecule has a symmetric shape and the dipoles cancel out then even molecules with lone pairs can be non polar. For example, another example of a non polar shape is square planar with four bonded atoms and two lone pairs of electron. But even symmetric shapes...
by jisulee1C
Mon Nov 18, 2019 9:42 pm
Forum: Ionic & Covalent Bonds
Topic: Lone pairs
Replies: 4
Views: 55

Re: Lone pairs

Depending on the shape and structure, the lone electrons can be either found on axial or equatorial electrons. This depends on the fact that electrons want to be placed far away from each other because electron electron repulsion is the greatest repulsion.
by jisulee1C
Fri Nov 15, 2019 12:36 pm
Forum: Trends in The Periodic Table
Topic: Question
Replies: 17
Views: 258

Re: Question

Ionization energy increases across the periodic table as does electronegativity which is a result electrons being more tightly held due to the nuclear pull increasing.
by jisulee1C
Fri Nov 15, 2019 12:32 pm
Forum: Lewis Structures
Topic: Ground-State Electron Configuration
Replies: 5
Views: 49

Re: Ground-State Electron Configuration

For both ground state electron configurations and electron configurations remember that if they ask for the full electron configuration you should not use noble gas configuration and instead start from 1s2 and list out the states.
by jisulee1C
Fri Nov 15, 2019 12:28 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: nonpolar molecules
Replies: 5
Views: 40

Re: nonpolar molecules

Some examples of nonpolar molecules are the diatomic gases such as H2. Also for molecules if dipole moments are canceled out by each other the molecule is nonpolar. An example of a nonpolar molecule because dipoles cancel each other out is carbon dioxide because the bonds are on exact opposite sides...
by jisulee1C
Fri Nov 15, 2019 12:18 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 6
Views: 49

Re: Polarity

A nonpolar molecule will only have Van Der Waals forces because they all have the same pull for electrons (electronegativity) while polar molecules have dipole forces because the two atoms have a difference in electronegativity that’s makes KWon atom pull them electron more than the other atom.
by jisulee1C
Fri Nov 15, 2019 12:14 pm
Forum: Dipole Moments
Topic: Shape of Molecules affect boiling point?
Replies: 7
Views: 79

Re: Shape of Molecules affect boiling point?

Also considering Van Der Waals forces it’s important to consider surface area. The larger the surface area the more forces there are. Because rod shaped has a larger surface area than spherical shape molecules it has more Van Der Waals forces and therefore will have a higher boiling point.
by jisulee1C
Fri Nov 08, 2019 11:35 pm
Forum: Dipole Moments
Topic: Dipole moments
Replies: 2
Views: 25

Re: Dipole moments

A pure dipole moment occurs between atoms that have a difference in electronegativity while induced dipole moment occurs due to the electrostatic attraction of electrons.
by jisulee1C
Fri Nov 08, 2019 11:33 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: H bonds and Intermolecular Forces
Replies: 4
Views: 36

Re: H bonds and Intermolecular Forces

Hydrogen bonds are a type of intermolecular force. Even though they are called hydrogen "bonds" they are attractions between molecules (NOF bonded with hydrogen) and another molecules (NOF bonded with hydrogen). Because the atom is highly electronegative atom (NOF) the attraction is so str...
by jisulee1C
Fri Nov 08, 2019 11:30 pm
Forum: Dipole Moments
Topic: Polar
Replies: 9
Views: 111

Re: Polar

Polar forces usually occur between those with a difference of electronegativity while dispersion forces occur between all molecules. For example, carbon dioxide has polar forces while chloride gas has dispersion forces.
by jisulee1C
Fri Nov 08, 2019 11:28 pm
Forum: Bond Lengths & Energies
Topic: dissociation energy
Replies: 5
Views: 33

Re: dissociation energy

For dissociation energy, the stronger the bond the higher the dissociation energy. A shorter bond has higher dissociation energy. For example, comparing a single bond to a double bond. A single bond is longer in length when compared to the double bond and therefore has a lower dissociation energy.
by jisulee1C
Fri Nov 08, 2019 11:26 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dispersion Force
Replies: 3
Views: 26

Re: Dispersion Force

Dispersion forces are a type of intermolecular force. Intermolecular forces occur between two molecules while intramolecular forces hold atoms together in a molecule.
by jisulee1C
Fri Nov 08, 2019 11:24 pm
Forum: Student Social/Study Group
Topic: midterm grades
Replies: 8
Views: 111

Re: midterm grades

And I think grades will be coming out next Wednesday.
by jisulee1C
Fri Nov 01, 2019 5:39 pm
Forum: Dipole Moments
Topic: identification
Replies: 3
Views: 41

Re: identification

Remember there are also induced dipoles that occur between atoms even if there isn’t a big difference of electro negativity. A dipole dipole moment occurs between t have a high difference of electronegativity such as as HF and HF while an induced dipole occurs between NN (even those without big elec...
by jisulee1C
Fri Nov 01, 2019 5:34 pm
Forum: Dipole Moments
Topic: Dipole Arrow
Replies: 3
Views: 27

Re: Dipole Arrow

The arrow always points toward the more negative atom because the more negative atom is pulling the electrons from the more positive atom.
by jisulee1C
Fri Nov 01, 2019 5:30 pm
Forum: Dipole Moments
Topic: induced dipole
Replies: 4
Views: 47

Re: induced dipole

An induced reaction is the attraction between atoms in a molecule because of their electrons. It is also known as dispersion, Van Der Waals, and London. All molecules have induced dipoles which are created because of the arrangement of electrons.
by jisulee1C
Fri Nov 01, 2019 5:13 pm
Forum: Bond Lengths & Energies
Topic: dissociation energy
Replies: 7
Views: 69

Re: dissociation energy

Dissociation energy is always positive because then dissociation energy is the energy required to break a bond and breaking a bond will always require an input of energy while forming bonds release energy.
by jisulee1C
Fri Nov 01, 2019 5:12 pm
Forum: Dipole Moments
Topic: direction of arrow
Replies: 2
Views: 28

Re: direction of arrow

In a dipole moment the dipole is represented by an arrow that points toward the partial negative because the more negative element has more attraction to the electron.
by jisulee1C
Sat Oct 26, 2019 11:59 am
Forum: Trends in The Periodic Table
Topic: ionic radius
Replies: 3
Views: 29

Re: ionic radius

I don't think we would have to calculate it since it is a periodic trend it would be helpful to remember that ionic radius generally decreases going across the periodic table (rows) and increases going down the periodic table (columns).
by jisulee1C
Sat Oct 26, 2019 11:56 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Formal Charge
Replies: 3
Views: 39

Re: Formal Charge

If the molecule cannot achieve a formal charge of zero for all the elements, remember that the more electronegative atom will keep the extra electrons. For example in sulfate ion (SO4 2-) the most stable structure is when two oxygens are double bonded to sulfur and the other two oxygens carry a form...
by jisulee1C
Sat Oct 26, 2019 11:53 am
Forum: Lewis Structures
Topic: Knowing bond types
Replies: 2
Views: 48

Re: Knowing bond types

Overall, it depends on the element that is being bonded with. For example, hydrogen can only form one bond while other atoms such as carbon and oxygen can form four bonds (want to fill valence shell to an octet). However, elements like Sulfur, Phosphorus, and Chloride can accommodate more than 8 val...
by jisulee1C
Sat Oct 26, 2019 11:50 am
Forum: Properties of Light
Topic: emission vs absorption
Replies: 2
Views: 37

Re: emission vs absorption

The absorption spectrum is when light has been absorbed by the atom thus you see a dip in the spectrum while emission spectra is when atoms releases photons that have certain wavelengths. Each element will have their own emission spectrum however, the Lyman and Balmer series is only applicable to hy...
by jisulee1C
Sat Oct 26, 2019 11:46 am
Forum: Ionic & Covalent Bonds
Topic: Partial Bond
Replies: 2
Views: 34

Re: Partial Bond

Partial bonds are when the structure can resonate or flip between two or more conformations. The nitrate ion has partial bonds because the double bonded oxygen can be at multiple locations (3 positions) therefore the actual structure would be a blend between the 3 structures.
by jisulee1C
Sat Oct 19, 2019 2:30 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Inner e- and Outer e-
Replies: 14
Views: 110

Re: Inner e- and Outer e-

The difference in position of the outer electron also determines the ionization energy needed to remove an electron. If there are more inner electrons, the outer electrons also receive less attraction from the neutron and therefore it will be easier to remove the outer electrons.
by jisulee1C
Sat Oct 19, 2019 2:26 pm
Forum: Trends in The Periodic Table
Topic: Problem 1.13
Replies: 2
Views: 46

Re: Problem 1.13

so this depends on the electron configuration of oxygen. because oxygen has 8 electrons the electron configuration will be 1s2 2s2 2p4 which means one of the electrons in the 2p orbital will occupy the same orbital as another electron which will result in electron electron repulsion therefore taking...
by jisulee1C
Sat Oct 19, 2019 2:21 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Balmer vs. Lyman Series
Replies: 4
Views: 52

Re: Balmer vs. Lyman Series

For the Lyman series,which corresponds to UV light, the electrons come to rest at the energy level n=1. and then for the Balmer series, which corresponds to visible light, the electrons come to rest at the energy level n=2
both can be used to compare lines for other elements.
by jisulee1C
Sat Oct 19, 2019 2:18 pm
Forum: Photoelectric Effect
Topic: One photon one atom interaction
Replies: 14
Views: 141

Re: One photon one atom interaction

After the energy of light surpasses the minimum energy needed to eject an electron, increasing the energy of light (frequency) will increase the amount of electrons. in fact they will share a direct relationship where one million photons will eject one million electrons.
by jisulee1C
Sat Oct 19, 2019 2:15 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Paired vs Parallel electrons
Replies: 5
Views: 32

Re: Paired vs Parallel electrons

^^yes. electrons will fill up each orbital until each orbital is occupied and then they will start to pair up. this is because the electrons will have electron to electron repulsion if they are in the same orbital which is not favorable.
by jisulee1C
Fri Oct 11, 2019 2:42 pm
Forum: Significant Figures
Topic: Sig Figs in Answer
Replies: 8
Views: 142

Re: Sig Figs in Answer

I would do to the hundredths place if it was a percentage or to 4 sig figs if there was no numbers given in the problem.
by jisulee1C
Fri Oct 11, 2019 2:37 pm
Forum: Properties of Electrons
Topic: Energy
Replies: 6
Views: 82

Re: Energy

When an electron is in an excited state it cannot maintain that high level of energy or that state therefore what happens is it falls back to the original or a lower energy level. And when it falls to a lower energy level the electron emits a photon of light otherwise known as a quanta.
by jisulee1C
Fri Oct 11, 2019 2:35 pm
Forum: Limiting Reactant Calculations
Topic: percent yield
Replies: 10
Views: 228

Re: percent yield

Usually the problem will ask specifically for the percentage yield and if it is not asked for then you don't need to calculate it.
by jisulee1C
Fri Oct 11, 2019 2:34 pm
Forum: Student Social/Study Group
Topic: Best Sessions
Replies: 12
Views: 116

Re: Best Sessions

I agree! The assigned homework problems and the post tests posted on Lavelle's website seem to be the best practice for tests in my opinion.
by jisulee1C
Fri Oct 11, 2019 2:33 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Accuracy and Precision
Replies: 8
Views: 137

Re: Accuracy and Precision

Accuracy vs Precision is going to be more applicable when we start analyzing lab data and looking at the results. Also accuracy relates to the concept of percentage yield because an accurate result would yield 100% or close to.
by jisulee1C
Mon Sep 30, 2019 9:42 pm
Forum: Limiting Reactant Calculations
Topic: 2 Limiting Reactants
Replies: 9
Views: 83

Re: 2 Limiting Reactants

Yes if the two limiting reactants form the same amount of product and it is less than the third reactant than this is possible although highly unlikely.
by jisulee1C
Mon Sep 30, 2019 9:40 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: What is a formula unit? (Question E9 from Handout #1)
Replies: 3
Views: 44

Re: What is a formula unit? (Question E9 from Handout #1)

A formula unit indicates the lowest whole number ratio of ions in an ionic compound. Compared to a molecule which would be the smallest for a covalently bonded compound.
by jisulee1C
Mon Sep 30, 2019 9:39 pm
Forum: Empirical & Molecular Formulas
Topic: Percentage Yield
Replies: 3
Views: 53

Re: Homework Problem M.1

Convert the grams of ammonia to moles of ammonia using molar mass of ammonia. Then using mole ratio convert the moles of ammonia to moles of hydrazine. Using the moles of hydrazine and the molar mass of hydrazine convert the moles to mass of hydrazine. After getting the expected yield of hydrazine, ...
by jisulee1C
Mon Sep 30, 2019 9:35 pm
Forum: Balancing Chemical Reactions
Topic: Fundamental L
Replies: 2
Views: 68

Re: Fundamental L

You have to start off with a balanced reaction where 2K (potassium metal) + H2 (hydrogen gas) = 2KH (potassium hydride). Then convert the grams of hydrogen to moles of hydrogen using molar mass. Use the mole ratio and dimensional analysis to convert the moles of hydrogen to moles of potassium and th...
by jisulee1C
Mon Sep 30, 2019 9:24 pm
Forum: Limiting Reactant Calculations
Topic: 2 Limiting Reactants
Replies: 9
Views: 83

Re: 2 Limiting Reactants

It depends on the chemical reaction but remember to convert to moles and find the amount each reactant makes of a specific product. Compare the amounts made by the two reactants and the one that makes less of the same product is the limiting reactant. There can be more than one limiting reactant but...
by jisulee1C
Sat Sep 28, 2019 10:32 pm
Forum: Limiting Reactant Calculations
Topic: Mass Yield of Product
Replies: 4
Views: 110

Re: Mass Yield of Product

After balancing the equation you can use the molar ratio where 1 mol of C6H9Cl3 is equal to 3 moles of AgCl and using this ratio and dimensional analysis will yield you 0.012 moles AgCl which you can then multiply by the molar mass of AgCl to get the final mass of AgCl produced.

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