Search found 50 matches

by Joelle 3L
Mon Dec 02, 2019 6:08 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: increasing pH and decreasing pH
Replies: 4
Views: 47

Re: increasing pH and decreasing pH

Yes, the pH scale and proton concentration works in reverse direction, so when one increases the other decreases.
by Joelle 3L
Mon Dec 02, 2019 6:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.9
Replies: 2
Views: 48

Re: 2E.9

Because ICl3 has two lone pairs and 3 bonds, it is t shape, which means that its bond angles would be 180 and less than 90 degrees.
by Joelle 3L
Mon Dec 02, 2019 6:01 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Quick Question
Replies: 4
Views: 167

Re: Quick Question

The l would be 1 following that sis l=0,p is l=1, d is l=2, and f is l=3
by Joelle 3L
Mon Dec 02, 2019 5:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.7
Replies: 2
Views: 36

Re: 2E.7

Because socl2 has 3 bonds and one lone pair, its shape is trigonal pyramidal. The bonds would be the same, which are less than 109.5.
by Joelle 3L
Mon Dec 02, 2019 5:57 pm
Forum: Conjugate Acids & Bases
Topic: Ligands
Replies: 12
Views: 112

Re: Ligands

A ligand is an ion or molecule that binds to a central metal atom in order to form a coordination complex. Essentially, it is an electron pair donor
by Joelle 3L
Thu Nov 28, 2019 3:48 pm
Forum: Hybridization
Topic: single vs double vs triple bonds
Replies: 4
Views: 55

Re: single vs double vs triple bonds

Single, double, and triple bonds each represent only one region of electron density. Other regions of electron density would include lone pairs. In C2H4 the hybridization of the carbon would be sp2 since there are three regions of electron density.
by Joelle 3L
Thu Nov 28, 2019 3:41 pm
Forum: Hybridization
Topic: PCl6
Replies: 3
Views: 83

Re: PCl6

The P in PCl6 has six regions of electron density. Therefore, to account for all these six regions the hybridization would be sp3d2. The p orbital can only hold up to three valence electrons
by Joelle 3L
Thu Nov 28, 2019 3:37 pm
Forum: Hybridization
Topic: 2F.15
Replies: 3
Views: 33

Re: 2F.15

Generally, the bond angle increases, s-character increase in the hybrid bond with a proportional relationship. The more s-character of hybrid orbital a molecule has, the greater the angle between the bond.
by Joelle 3L
Thu Nov 28, 2019 3:28 pm
Forum: Hybridization
Topic: Sigma and Pi Bonds
Replies: 21
Views: 150

Re: Sigma and Pi Bonds

Every single bond will be a sigma bonds. Every double bond would have one sigma bond then a pi bond. Triple bonds include one sigma bond and two pi bonds.
by Joelle 3L
Thu Nov 28, 2019 3:22 pm
Forum: Hybridization
Topic: double bonds
Replies: 7
Views: 76

Re: double bonds

When focusing on hybridization, you look at the regions of electron density. Therefore, a single, double, or triple bond between atoms would all be considered one electron density region. On the other hand, lone pairs would be considered as well in hybridization.
by Joelle 3L
Thu Nov 21, 2019 4:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 3
Views: 31

Re: bond angles

In the solutions at the back of the book, it says "slightly less than 109.5 degrees" so I think it is sufficient to answer in this way and we do not need to actually say the bond angles but give an approximation
by Joelle 3L
Thu Nov 21, 2019 4:41 pm
Forum: Hybridization
Topic: hybridization on the test?
Replies: 10
Views: 141

Re: hybridization on the test?

The announcement on his website said the material on the test covers material after midterm to end of sigma and pi bonds. So there will not be hybridization
by Joelle 3L
Thu Nov 21, 2019 4:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Octahedral
Replies: 6
Views: 74

Re: Octahedral

Although it is a six bond geometry it is called octahedral because when connected and focusing on the geometry, there are eight faces, therefore having the prefix octa-.
by Joelle 3L
Thu Nov 21, 2019 4:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 6
Views: 76

Re: Bond Angles

Yes, lone pairs on the central atom would cause bond angles to be slightly less since electrons repel each other and this repulsion must be minimized by arranging them in a particular manner in 3D space.
by Joelle 3L
Thu Nov 21, 2019 4:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: XA2E2
Replies: 9
Views: 86

Re: XA2E2

Yes, it would be called bent since there are actually two bonds. This is because lone pairs do influence molecular shape but only atom positions are used to name the shape.
by Joelle 3L
Wed Nov 13, 2019 11:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.11
Replies: 1
Views: 30

Re: 2E.11

When drawing iodine trichloride there are five electron groups, however it also has two lone pairs of electrons. Therefore, it is t-shaped. Trigonal planar only has three electron groups and no lone pairs of electrons
by Joelle 3L
Wed Nov 13, 2019 11:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: arrangment and strength of IMFS
Replies: 4
Views: 55

Re: arrangment and strength of IMFS

Dispersion forces increase with in strength with increasing molecular size. Also molecular shape affects intermolecular attraction. The greater the surface contact the greater boiling point and therefore long dispersion forces.
by Joelle 3L
Wed Nov 13, 2019 11:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E9
Replies: 3
Views: 45

Re: 2E9

Trigonal bipyramidal does have does have five groups of electrons. However, it does not have any lone pairs like the ones you drew in the lewis structure. A structure with five electron groups and 2 lone pairs is called T shape. You should look at the number of lone pairs when naming.
by Joelle 3L
Wed Nov 13, 2019 11:16 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: What’s the Difference
Replies: 6
Views: 213

Re: What’s the Difference

The tendency of an anion to become polarized by the cation is polarizability while the ability of a cation to distort an anion is polarization power. When looking at more polarizability you would look at a higher electron to proton ration and when looking at polarization power you would look at high...
by Joelle 3L
Wed Nov 13, 2019 11:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Problem 2E 7
Replies: 5
Views: 91

Re: Problem 2E 7

The bond lengths would equal the same due to delocalized electrons, meaning there would be resonance structures if you drew it out. The bonds would be the average and the same.
by Joelle 3L
Sat Nov 09, 2019 12:42 am
Forum: Student Social/Study Group
Topic: midterm grades
Replies: 8
Views: 144

Re: midterm grades

My TA said we will be getting our midterm after Wednesday's lecture next week.
by Joelle 3L
Sat Nov 09, 2019 12:38 am
Forum: Quantum Numbers and The H-Atom
Topic: Quantum numbers
Replies: 12
Views: 291

Re: Quantum numbers

The angular momentum is denoted as l and is the quantum number associated with the angular momentum of an atomic electron. It determines the shape of the electron's orbital.
by Joelle 3L
Sat Nov 09, 2019 12:36 am
Forum: Trends in The Periodic Table
Topic: atomic radius
Replies: 7
Views: 149

Re: atomic radius

When you go across a period there are more protons in an element, making it have a greater effective nuclear charge. The electrons would be added to the same energy levels but since there are more protons going across a period the protons would have a tronger pull making the atomic radius smaller.
by Joelle 3L
Sat Nov 09, 2019 12:32 am
Forum: Dipole Moments
Topic: Polar
Replies: 9
Views: 140

Re: Polar

Non-polar would show charge distribution as symmetric while polar molecules would show an asymmetric charge distribution. You can also use electronegativity to determine this.
by Joelle 3L
Sat Nov 09, 2019 12:27 am
Forum: Student Social/Study Group
Topic: Dipole Moment
Replies: 5
Views: 83

Re: Dipole Moment

A dipole moment happens when there is a separation of charge. It can occur in both ionic bonds and covalent bonds and are due to difference in electronegativity. It describes two opposite charges separated by distance.Essentially, it is a measure of the polarity of the molecule.
by Joelle 3L
Sat Nov 02, 2019 12:29 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Energy change and Energy of photon
Replies: 5
Views: 55

Re: Energy change and Energy of photon

The energy in a hydrogen atom depends on the energy of the electron. When you move from a higher state to a lower state, it decreases energy and the atom emits photons. The photon energy will always be positive.
by Joelle 3L
Sat Nov 02, 2019 12:13 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Indeterminacy Equation
Replies: 6
Views: 227

Re: Heisenberg Indeterminacy Equation

Delta x and delta p were multiplied to find the value. So if one uncertainty is reduced the other increases and vice versa. I think they used advanced mathematics and showed that the best was done with for the measurement of position and moment was with the inclusion of 4 pi
by Joelle 3L
Sat Nov 02, 2019 12:06 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Energy of orbitals
Replies: 2
Views: 37

Re: Energy of orbitals

The energy of orbitals refers to the energy required to take an electron present in that orbital or the energy released when an electron is dded to the orbital.
by Joelle 3L
Sat Nov 02, 2019 11:56 am
Forum: Trends in The Periodic Table
Topic: Noble Gases
Replies: 10
Views: 149

Re: Noble Gases

Noble gases would not follow any of the periodic trends. They are the least reactive elements and are nearly inert because they have a full valence electron shell, with little tendency to donate or accept electrons.
by Joelle 3L
Sat Nov 02, 2019 11:50 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1F.19: s-block
Replies: 2
Views: 45

Re: 1F.19: s-block

s-blocks elements are typically more reactive because they have one or two electrons in their outermost shell. Therefore, they become stable by giving up an electron (low ionization energy), making them more reactive than a p-block element that has higher ionization energy.
by Joelle 3L
Sat Oct 26, 2019 2:44 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge and Molecules
Replies: 4
Views: 63

Re: Formal Charge and Molecules

It is not a coincidence since the sum of the formal charges in an ion should always equal the charge of the ion.
by Joelle 3L
Sat Oct 26, 2019 2:40 pm
Forum: Sigma & Pi Bonds
Topic: Difference between Sigma & Pi
Replies: 5
Views: 90

Re: Difference between Sigma & Pi

Both sigma and pi bonds are covalent bonds and form by overlap of atomic orbitals. Sigma bonds are formed by end-to-end overlapping and Pi bonds are when the lobe of one atomic orbital overlaps another. Generally sigma bonds are stronger than pi bonds. They can occur in the same molecule.
by Joelle 3L
Sat Oct 26, 2019 2:32 pm
Forum: Lewis Structures
Topic: D-block
Replies: 2
Views: 52

Re: D-block

To determine the amount of valence electrons the D-block elements have look at their group number, which is equal to the number of electrons in the "valence shell." This should work if you are using the definition of valence shell to being the outermost shell.
by Joelle 3L
Sat Oct 26, 2019 2:26 pm
Forum: Ionic & Covalent Bonds
Topic: Expanded Valence Shells
Replies: 4
Views: 46

Re: Expanded Valence Shells

An expanded valence shell is when there are more than eight valence electrons. Elements that have an expanded valence shell includes phosphorus or sulfur. These can only occur when the valence shell has enough orbitals to accommodate the extra electrons.
by Joelle 3L
Sat Oct 26, 2019 2:23 pm
Forum: Resonance Structures
Topic: Lewis Structure vs. Resonance Structure
Replies: 4
Views: 67

Re: Lewis Structure vs. Resonance Structure

When more than one Lewis Structure can be drawn, the molecule or ion is said to have resonance. The individual Lewis structures are called resonance structures. Therefore, resonance structures are used when one Lewis structure for a single molecules can't fully be described by the bonding that occur...
by Joelle 3L
Sun Oct 20, 2019 2:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework for week 4
Replies: 3
Views: 34

Re: Homework for week 4

In my discussion my TA said we will be working on quantum world for Monday and chemical bonding for the rest of the week. So we can choose either quantum world or chemical bonding for week 4 homework.
by Joelle 3L
Sun Oct 20, 2019 2:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 6
Views: 45

Re: Nodal Planes

In an orbitals, nodes are non-spherical regions where the electron cannot exist. This can be a nodal plane or nodal cone. The s- orbitals do not have a nodal plane because the entire orbital is the same phase.
by Joelle 3L
Sun Oct 20, 2019 2:27 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Pauli Exclusion Principle
Replies: 9
Views: 513

Re: Pauli Exclusion Principle

The Pauli Exclusion Principle says that no two electrons can have the same sign. For instance, an orbital can contain two electrons at most and both electrons must have opposing signs. This can be represented an upward and downward arrow visually.
by Joelle 3L
Sun Oct 20, 2019 2:22 pm
Forum: Trends in The Periodic Table
Topic: Atomic radii
Replies: 9
Views: 135

Re: Atomic radii

Atomic radii is one of the periodic trends. Atomic radius decreases as you move to the right of the period table because electrons are being added to the same shell but also protons are added to the nucleus. This would mean it makes it more positively charged and therefore greater nuclear attraction...
by Joelle 3L
Sun Oct 20, 2019 2:14 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Aufbau Principle
Replies: 3
Views: 37

Re: Aufbau Principle

The Aufbau principle means that electrons are added to orbitals as protons are added to the atom. Therefore, lower electron orbitals fill before the higher orbitals. This process can be seen as "building up" the electron shell. It outlines the rules on how electrons are organized in electr...
by Joelle 3L
Sat Oct 12, 2019 2:35 pm
Forum: Photoelectric Effect
Topic: Energy in Photoelectric Effect
Replies: 5
Views: 41

Re: Energy in Photoelectric Effect

Energy below a certain threshold frequency, no matter how intense, will not cause any electrons to be emitted. Energy above the threshold frequency, even if it's not very intense, will always cause electrons to be emitted.
by Joelle 3L
Sat Oct 12, 2019 2:26 pm
Forum: Properties of Electrons
Topic: wave properties of electrons
Replies: 4
Views: 26

Re: wave properties of electrons

I think the electron would exhibit wave-particle duality. Everything has a wavelength, but the wave properties of matter are only observable for very small objects. Therefore I think it would still exhibit wavelength properties to a lesser extent.
by Joelle 3L
Sat Oct 12, 2019 2:15 pm
Forum: Properties of Light
Topic: Color of Light
Replies: 2
Views: 44

Re: Color of Light

Light is made up of wavelengths of light, each with their own color. This region is visible light. In the atomic Spectra, an electric current is passed through a low-pressure sample of hydrogen gas. The electric field strips off electrons from the H2 molecules. These then form energetically excited ...
by Joelle 3L
Sat Oct 12, 2019 2:04 pm
Forum: Properties of Light
Topic: Adding formulas
Replies: 5
Views: 64

Re: Adding formulas

Plank's equation, E=hv and the wave equation equation, c=wavelength*frequency can be rearranged. Frequency can be replaced with c/lambda, resulting in the equation. This shows the energy of a photon is directly proportional to its frequency and inversely proportional to the wavelength
by Joelle 3L
Sat Oct 12, 2019 1:55 pm
Forum: Properties of Light
Topic: 1A.11
Replies: 2
Views: 41

1A.11

In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series or Lyman series, as shown in Fig. 1A.10). What is common to the lines within a series that makes grouping them together logical?
by Joelle 3L
Thu Oct 03, 2019 3:22 pm
Forum: Significant Figures
Topic: General sig figs question
Replies: 5
Views: 101

Re: General sig figs question

When determining the amount of sig figs for adding and subtracting you would just round the least amount of decimal places. For example 45.777+23.1=68.9. However for multiplying and subtracting, the rules are different. The least amount of sig figs in the number would determine how you would round. ...
by Joelle 3L
Thu Oct 03, 2019 3:17 pm
Forum: Empirical & Molecular Formulas
Topic: Test Materials
Replies: 13
Views: 223

Re: Test Materials

I read from another forum that we will be given the periodic table and formula sheet for quizzes, midterms, and final. But in my opinion we should memorize the constant and other commonly used forumlas just in case.
by Joelle 3L
Thu Oct 03, 2019 3:13 pm
Forum: Balancing Chemical Reactions
Topic: H.25 Question
Replies: 3
Views: 102

H.25 Question

The question states phosphorus and oxygen react to form two different phosphorus oxides. The mass percentage of phosphorus in one of these oxides is 43.64%; in the other, it is 56.34%. I answer parts a and b correctly, but for c I got it incorrect because I did not know phosphorus alone had the subs...
by Joelle 3L
Thu Oct 03, 2019 3:06 pm
Forum: SI Units, Unit Conversions
Topic: Finding Molar Mass
Replies: 3
Views: 56

Re: Finding Molar Mass

The chemical equation would be Na2CO3 * 10H2O -> Na2CO3 + 10H2O. You would find the molar mass of this equation by multiplying the factors by their respective molar masses. Therefore, 2(22.99) + 12.01 + 3(16) +10(18.02) = 286.19g.
by Joelle 3L
Thu Oct 03, 2019 3:01 pm
Forum: SI Units, Unit Conversions
Topic: knowing how many sig figs to use
Replies: 17
Views: 283

Re: knowing how many sig figs to use

I remember in class him saying not to round till the very last step but in showing work he would round in the lecture slides to neatly show the steps since the focus in the recent lectures were not actual sig figs. I suggest doing this on homework as well

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