Search found 51 matches

by Sejal Parsi 3K
Thu Dec 17, 2020 7:59 am
Forum: Lewis Acids & Bases
Topic: Are these actually acidic?
Replies: 5
Views: 24

Re: Are these actually acidic?

I believe they would show up as being acidic.
by Sejal Parsi 3K
Thu Dec 17, 2020 7:58 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating H+
Replies: 17
Views: 46

Re: Calculating H+

You would do 10^(-pH) to get the H+ concentration.
by Sejal Parsi 3K
Thu Dec 17, 2020 7:56 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Why isn't HF a strong acid?
Replies: 23
Views: 130

Re: Why isn't HF a strong acid?

It’s because fluorine is so electronegative that in a solution, it won’t give up its hydrogen easily, and strong acids tend to dissociate easier in solutions.
by Sejal Parsi 3K
Thu Dec 17, 2020 7:53 am
Forum: Photoelectric Effect
Topic: Decimals
Replies: 6
Views: 38

Re: Decimals

I think it is normally based on significant figures, but I typically keep between 4-5.
by Sejal Parsi 3K
Thu Dec 17, 2020 7:53 am
Forum: Sigma & Pi Bonds
Topic: Pi Bonds
Replies: 15
Views: 96

Re: Pi Bonds

Pi bonds only apply to covalent bonds!
by Sejal Parsi 3K
Thu Dec 17, 2020 7:52 am
Forum: Quantum Numbers and The H-Atom
Topic: Why does nickel have an expanded octet?
Replies: 5
Views: 33

Re: Why does nickel have an expanded octet?

Nickel can hold up to 10 total valence electrons because of its 3d and 4s subshells.
by Sejal Parsi 3K
Thu Dec 17, 2020 7:50 am
Forum: Lewis Acids & Bases
Topic: Water
Replies: 62
Views: 483

Re: Water

Water is amphoteric so it can act as both!
by Sejal Parsi 3K
Thu Dec 17, 2020 7:48 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Organic vs Inorganic
Replies: 5
Views: 52

Re: Organic vs Inorganic

Organic molecules have carbon-hydrogen bonds while inorganic molecules don’t have carbon-hydrogen bonds.
by Sejal Parsi 3K
Thu Dec 17, 2020 7:47 am
Forum: Calculating the pH of Salt Solutions
Topic: pH formula?
Replies: 46
Views: 932

Re: pH formula?

pH= -log[H+] and you don’t need to know how to derive it.
by Sejal Parsi 3K
Thu Dec 17, 2020 7:46 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Hard/Soft Water
Replies: 4
Views: 29

Re: Hard/Soft Water

Hard water contains more mineral ions like Ca2+ and Mg2+, soft water is less alkaline.
by Sejal Parsi 3K
Thu Dec 17, 2020 7:43 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Difference between pH and pOH
Replies: 12
Views: 60

Re: Difference between pH and pOH

As everyone has said, pH and pOH are the H+ and OH- concentrations. Kb is the base dissociation constant, so the larger the Kb the stronger the bases and pKb is also just another way to write Kb.
by Sejal Parsi 3K
Tue Dec 01, 2020 3:19 am
Forum: Biological Examples
Topic: Biological function of sigma and pi bonds
Replies: 4
Views: 48

Re: Biological function of sigma and pi bonds

I think that is almost everything you need to know. You should probably also know that pi bonds form when orbitals overlap side-to-side and sigma bonds form when orbitals overlap end-to-end.
by Sejal Parsi 3K
Tue Dec 01, 2020 3:02 am
Forum: Hybridization
Topic: unhybridized orbitals
Replies: 4
Views: 49

Re: unhybridized orbitals

Hi! As stated above, generally all sigma bonds are in hybridized orbitals.
by Sejal Parsi 3K
Tue Dec 01, 2020 2:53 am
Forum: Naming
Topic: Order of Molecules
Replies: 6
Views: 57

Re: Order of Molecules

Hi! As they said above, I think the order of the ligands doesn't matter so long as the cation is the first one.
by Sejal Parsi 3K
Tue Dec 01, 2020 2:38 am
Forum: Hybridization
Topic: Sigma and Pi bonds
Replies: 21
Views: 147

Re: Sigma and Pi bonds

Sigma bonds are single bonds and pi bonds are in double and triple bonds. In a double bond, one bond will be a sigma bond and the other a pi bond, and for triple bonds, there is one sigma bond and two pi bonds.
by Sejal Parsi 3K
Tue Dec 01, 2020 2:33 am
Forum: Hybridization
Topic: How to simply determine hybridization
Replies: 27
Views: 184

Re: How to simply determine hybridization

To determine hybridization, you count the number of atoms that are bonded to the atom and add this number to the number of lone pairs there are around the atom. sp goes with 2, sp2 goes with 3, etc.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:39 am
Forum: Lewis Structures
Topic: Central Atom Question
Replies: 20
Views: 132

Re: Central Atom Question

Because Hydrogen only likes to form one bond, it can’t be the central atom. They are normally added to the end of Lewis structures because of this.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:37 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Stable Structures
Replies: 10
Views: 65

Re: Stable Structures

Yes, as stated above, I think we always consider the most stable structure while determining the shapes of molecules.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:35 am
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Boiling and Melting point
Replies: 18
Views: 117

Re: Boiling and Melting point

The higher the boiling point or melting point is, it takes more energy to break the bonds, which would be the intermolecular forces.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:31 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape Names
Replies: 50
Views: 284

Re: Shape Names

Yes, it can be called bent or angular!
by Sejal Parsi 3K
Sat Nov 21, 2020 4:30 am
Forum: Hybridization
Topic: pi bonds
Replies: 12
Views: 203

Re: pi bonds

A pi bond is created when two p orbitals overlap side by side, with electron density concentrated above and below the plane of the bonding atoms.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:27 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair E-
Replies: 47
Views: 257

Re: Lone Pair E-

Yes, lone pair electrons do count and will affect the shape because of their strong repulsion.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:22 am
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 33
Views: 200

Re: Covalent Character

Yes, I agree with the post above. I remember Lavelle saying that the smaller the electronegativity between the atoms, the more covalent they are.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:21 am
Forum: Dipole Moments
Topic: Polarity
Replies: 30
Views: 152

Re: Polarity

Thought there are dipole moments happening between atoms in a molecule, they can cancel out, making the molecule non polar.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:18 am
Forum: Formal Charge and Oxidation Numbers
Topic: Best Formal Charge Equations
Replies: 24
Views: 130

Re: Best Formal Charge Equations

I agree with the dots and lines method as well. It seems easier to understand and do as well, counting each dot and line as 1.
by Sejal Parsi 3K
Sat Nov 21, 2020 4:04 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook 2E #27c
Replies: 6
Views: 23

Re: Textbook 2E #27c

Hi! Like they said above, the C-Cl bond is polar while the C-H bond is non-polar, so the dipoles won’t cancel out.
by Sejal Parsi 3K
Mon Nov 09, 2020 4:29 am
Forum: Ionic & Covalent Bonds
Topic: Difference Between Ionic & Covalent Bonds
Replies: 11
Views: 63

Re: Difference Between Ionic & Covalent Bonds

Ionic bonds are formed when a metal transfers its electron to a nonmetal to form an electrostatic attraction between them, while covalent bonds are from the sharing of electrons between nonmetals.
by Sejal Parsi 3K
Mon Nov 09, 2020 4:27 am
Forum: Trends in The Periodic Table
Topic: positive and negative ion
Replies: 14
Views: 73

Re: positive and negative ion

Hi! An element with a negatively charged ion will have a larger radius because it has additional electrons than one that's positively charged. It's good to check the periodic table and follow trends if it is not for the same element though.
by Sejal Parsi 3K
Mon Nov 09, 2020 4:20 am
Forum: Ionic & Covalent Bonds
Topic: Size of Bonds
Replies: 28
Views: 99

Re: Size of Bonds

Double bonds are shorter because they have two more electrons than single bonds, so their attraction to the nucleus is stronger, pulling them closer and making the bond shorter.
by Sejal Parsi 3K
Mon Nov 09, 2020 4:18 am
Forum: Ionic & Covalent Bonds
Topic: Electronegativity
Replies: 16
Views: 90

Re: Electronegativity

This because it only needs one electron to complete its shell, so it is highly reactive.
by Sejal Parsi 3K
Mon Nov 09, 2020 4:02 am
Forum: Electronegativity
Topic: Confusion between electronegativity and electron affinity
Replies: 15
Views: 109

Re: Confusion between electronegativity and electron affinity

Electronegativity describes how well an atom attracts electrons while electron affinity shows the amount of energy released when an electron is added to make it negative. Electronegativity is also a calculated value.
by Sejal Parsi 3K
Tue Nov 03, 2020 2:25 am
Forum: Properties of Light
Topic: Wavelenght
Replies: 17
Views: 109

Re: Wavelenght

Gamma rays have the shortest wavelength, but the highest energy or frequency.
by Sejal Parsi 3K
Tue Nov 03, 2020 2:23 am
Forum: Lewis Structures
Topic: sides
Replies: 12
Views: 120

Re: sides

Yes, I believe it does not matter what side you put it.
by Sejal Parsi 3K
Tue Nov 03, 2020 2:20 am
Forum: Trends in The Periodic Table
Topic: # of electrons
Replies: 23
Views: 118

Re: # of electrons

Hi! The number of electrons would be the same as the atomic number and if you are referring to the valence electrons, it would be the amount of electrons in the incomplete shell of the element.
by Sejal Parsi 3K
Tue Nov 03, 2020 2:16 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 11
Views: 333

Re: Formal Charge

Regardless of the fact that it is an electron, it will be 1-.
by Sejal Parsi 3K
Tue Nov 03, 2020 2:14 am
Forum: Lewis Structures
Topic: charge by square bracket
Replies: 8
Views: 61

Re: charge by square bracket

Hi! The sign corresponds to the charge of the molecule since the structure itself may not show it. If the ion is positive, there will be a positive sign outside the bracket; if the ion is negative, there will be a negative sign outside the bracket.
by Sejal Parsi 3K
Thu Oct 29, 2020 2:32 am
Forum: Molarity, Solutions, Dilutions
Topic: Dilution module
Replies: 6
Views: 65

Re: Dilution module

As stated above, typically you use the same units across the problem, but if the answer is in another unit, you can simply convert your answer! Also, out of practicality in labs, they may use mL instead of L if that seems more reasonable to use for the measurement.
by Sejal Parsi 3K
Thu Oct 29, 2020 2:22 am
Forum: DeBroglie Equation
Topic: Conversions
Replies: 9
Views: 94

Re: Conversions

Hi! I don’t think we will need to memorize those, and mostly everything needed will be on the reference sheet, periodic table, or given in the problem!
by Sejal Parsi 3K
Thu Oct 29, 2020 2:20 am
Forum: General Science Questions
Topic: polyatomic ions
Replies: 6
Views: 97

Re: polyatomic ions

Hi! I believe Dr. Lavelle mentioned in a lecture that we would not have to memorize polyatomic ions and that if there is something we have not covered, he would provide us with any needed information!
by Sejal Parsi 3K
Thu Oct 29, 2020 2:18 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3d and 4s orbitals
Replies: 9
Views: 77

Re: 3d and 4s orbitals

Hi, until the 4s level is completely filled, the electrons won’t go into the 3d level. But once electrons go into 3d, that will be the level with lower energy, so 3d is written first.
by Sejal Parsi 3K
Thu Oct 29, 2020 2:14 am
Forum: Einstein Equation
Topic: E=pc vs E=hv
Replies: 15
Views: 144

Re: E=pc vs E=hv

I think we use E=hv to find the energy of a photon using Plank's constant and the frequency of light, so most of the times when we are dealing with frequency. While E=pc also finds the energy of a photon, it uses the speed of light and momentum of the photon, so it's important for De Broglie's equat...
by Sejal Parsi 3K
Mon Oct 19, 2020 3:31 am
Forum: Properties of Light
Topic: Frequency vs Wavelength
Replies: 22
Views: 141

Re: Frequency vs Wavelength

As said, frequency plays a role in characteristics of waves because if the frequency is higher, then the wave will be shorter. And if the frequency is lower, the wave will be higher because frequency and wavelength are inversely proportional as shown by the equation.
by Sejal Parsi 3K
Mon Oct 19, 2020 3:26 am
Forum: General Science Questions
Topic: Sig Figs
Replies: 14
Views: 80

Re: Sig Figs

I think it’s best to use the amount of sig figs given in the problem, and to not round your answer until the very end to keep it accurate. I believe my TA said we could be partially penalized if our sig figs are way off.
by Sejal Parsi 3K
Mon Oct 19, 2020 3:24 am
Forum: Properties of Electrons
Topic: Electrons Excited or Ejected
Replies: 19
Views: 142

Re: Electrons Excited or Ejected

I believe the simple explanation is that excited electrons are electrons with energy that move up energy levels within an atom, while ejected electrons are electrons that have been removed from the atom itself.
by Sejal Parsi 3K
Mon Oct 19, 2020 3:19 am
Forum: Properties of Electrons
Topic: Energy levels
Replies: 8
Views: 56

Re: Energy levels

Hey! I think this is because the closer you are to the nucleus, the harder it is to go up energy levels because of the positive pull from the nucleus. But as you get further away from the nucleus, the pull is less so the energy levels are smaller and take less energy to get to.
by Sejal Parsi 3K
Mon Oct 19, 2020 3:16 am
Forum: Photoelectric Effect
Topic: Light Intensity
Replies: 23
Views: 107

Re: Light Intensity

Hey! That’s correct, increasing the intensity of the light meant increasing the brightness which is more photons. Had they increased the frequency/changed the wavelength, the experiment would have worked.
by Sejal Parsi 3K
Fri Oct 09, 2020 2:18 am
Forum: SI Units, Unit Conversions
Topic: Sig figs and molar mass
Replies: 18
Views: 101

Re: Sig figs and molar mass

Hi, as said by everyone above, it is best to use as many sig figs as given on the periodic table, and then to round your final answer appropriately to the sig figs given within the problem.
by Sejal Parsi 3K
Fri Oct 09, 2020 2:16 am
Forum: Balancing Chemical Reactions
Topic: Naming compounds
Replies: 21
Views: 192

Re: Naming compounds

I don’t think we have to memorize just yet how to name compounds according to what Dr. Lavelle said during a lecture. I assume we may have to know basic ones in the future though.
by Sejal Parsi 3K
Fri Oct 09, 2020 2:11 am
Forum: Balancing Chemical Reactions
Topic: Fractions
Replies: 14
Views: 108

Re: Fractions

I think it is preferred that moles always be in the nearest whole number. If you get moles as a fraction, you could multiply it with the closest number in order to get a whole number and do so to the rest of the equation if applicable.
by Sejal Parsi 3K
Fri Oct 09, 2020 2:08 am
Forum: Significant Figures
Topic: Sig Fig usage on exams
Replies: 11
Views: 109

Re: Sig Fig usage on exams

I think sig figs are typically important to keep in mind as it gives accuracy to the problem based on the numbers given. If you are rounding, you should probably round to a reasonable number or round in order to get the right amount of sig figs. I also saw someone ask about when to use scientific no...
by Sejal Parsi 3K
Fri Oct 09, 2020 2:03 am
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Reactions Order
Replies: 31
Views: 236

Re: Balancing Chemical Reactions Order

Hi, as everyone has said above, there is no specific order to balance equations, but there are some tricks that can make it easier. My high school teacher also taught me to balance metals, nonmetals, hydrogen, and then oxygen as the numbers are easier to clean up that way. Also, in a lot of the equa...

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