Search found 62 matches

by Andrew Yoon 3L
Fri Jan 15, 2021 8:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant
Replies: 2
Views: 11

Re: Equilibrium Constant

I'm not entirely sure if there is a high pressure that there will be an higher equilibrium constant. All that is important is that the equilibrium constant stays the same if we change the pressure or the volume. Only a change in temperature will change the k value.
by Andrew Yoon 3L
Fri Jan 15, 2021 8:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Problem 5I #15
Replies: 3
Views: 16

Re: Textbook Problem 5I #15

Since the problem gives the moles of NH3 in the beginning of the reaction, you would write 0.2 mol/L for the initial concentration for NH3. Then, you would solve for x just how you would for any other ICE box.
by Andrew Yoon 3L
Fri Jan 15, 2021 8:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #3
Replies: 5
Views: 33

Re: Sapling #3

When your squaring your products, make sure you are squaring both the variable and the coefficient. (2x)^2 should equal 4x^2. Next, you should multiply out the denominator. Then, you should solve for x using the quadratic formula.
by Andrew Yoon 3L
Fri Jan 15, 2021 8:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong Acid and Base
Replies: 4
Views: 20

Re: Strong Acid and Base

H+ or OH- would have molar concentrations because when strong acids/bases react with water, they completely dissociate. H+ can also be written as H3O+. Since H+ and OH- are products in the reaction, they must have a concentration. Dissociation does not mean they disappear.
by Andrew Yoon 3L
Fri Jan 15, 2021 8:41 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: K in endo and exo when temp. decreases
Replies: 11
Views: 42

Re: K in endo and exo when temp. decreases

When decreasing the temp, the k value will increase. This is an exothermic reaction. You can also see if the reaction is exothermic if delta H is negative.
by Andrew Yoon 3L
Thu Jan 07, 2021 10:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE tables
Replies: 11
Views: 63

Re: ICE tables

Just to ask, if we are given a value for the products in the question as well has initial values for the reactants, would we include them in the I part of the ICE table?
by Andrew Yoon 3L
Thu Jan 07, 2021 10:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.i #11
Replies: 4
Views: 24

Re: 5.i #11

You have to change mmol to mol/L. First change to mmol to mol and then divide by volume (L) to get the molarity.
by Andrew Yoon 3L
Thu Jan 07, 2021 10:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW problem
Replies: 4
Views: 51

Re: HW problem

For this question, you would need to add two or more equations together. Adding equations together is the same as adding numbers except the substances on their sides, stay on their respective sides (so like on the left or on the right). Next, in order to get the equation to exactly match with all th...
by Andrew Yoon 3L
Thu Jan 07, 2021 10:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: dobule arrows
Replies: 6
Views: 49

Re: dobule arrows

"<<" refers to how much smaller (or larger depending on what you're looking at) the number/variable is compared to the other number/variable.
by Andrew Yoon 3L
Thu Jan 07, 2021 10:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc
Replies: 11
Views: 36

Re: Kc

For Kc, you would use the molar concentration of the substances in the system. If the question asked you to find the Kp, you would use partial pressures of the substances in the system.
by Andrew Yoon 3L
Tue Dec 15, 2020 2:40 pm
Forum: Air Pollution & Acid Rain
Topic: acid rain
Replies: 5
Views: 184

Re: acid rain

For acid rain, you should know that it is formed in the atmosphere when carbon dioxide reacts with water, which produces carbonic acid and becomes acid rain.

H2O + CO2 --> H2CO3
by Andrew Yoon 3L
Tue Dec 15, 2020 2:25 pm
Forum: Conjugate Acids & Bases
Topic: Fundamental J.13 Part C
Replies: 4
Views: 41

Re: Fundamental J.13 Part C

For bronsted acid and bases and lewis acids and bases, it's pretty clear on what is a conjugate acid/base. However, I'm not entirely sure if neutralized reactions have a conjugate acid and base. I don't think they do because the products are water and a salt.
by Andrew Yoon 3L
Tue Dec 15, 2020 2:12 pm
Forum: Amphoteric Compounds
Topic: Recognizing Amphoteric Compounds
Replies: 9
Views: 153

Re: Recognizing Amphoteric Compounds

^^ yeah an amphoteric compound is a compound that can be an acid or base in a reaction. The most basic example is water, H2O. Since it can both accept or donate an H+, it can be bronsted acid or base.
by Andrew Yoon 3L
Tue Dec 15, 2020 2:09 pm
Forum: Polyprotic Acids & Bases
Topic: Polyprotic Acids and Bases
Replies: 4
Views: 43

Re: Polyprotic Acids and Bases

Yeah so polyprotic acid and bases accept/donate more than 1 proton, in other words H+.
by Andrew Yoon 3L
Tue Dec 15, 2020 2:05 pm
Forum: Calculating the pH of Salt Solutions
Topic: Solving PH/PoH
Replies: 11
Views: 84

Re: Solving PH/PoH

Yeah just know the relationship between pH, pOH, [H+], [OH-]. If you know the relationships among them well, you should be good!
by Andrew Yoon 3L
Sun Dec 06, 2020 10:34 pm
Forum: Identifying Acidic & Basic Salts
Topic: Types of Salts
Replies: 7
Views: 214

Re: Types of Salts

There are no such things as a strong or weak salt because salts do not affect the pH.
by Andrew Yoon 3L
Sun Dec 06, 2020 10:21 pm
Forum: Conjugate Acids & Bases
Topic: NH3
Replies: 4
Views: 15

Re: NH3

When NH3 interacts with H2O, it doesn't give up an H to H2O because H3O is very unstable. So rather, it will accept an H from H2O. The products would be NH4+ and OH-. Since it is accepting an H, which can be thought of as a proton, NH3 is an base and H2O is an acid.
by Andrew Yoon 3L
Sun Dec 06, 2020 10:15 pm
Forum: Lewis Acids & Bases
Topic: lewis vs bronsted
Replies: 10
Views: 61

Re: lewis vs bronsted

Lewis acids and bases focus on the transfer of lone pairs of electrons. Bronstead acids and bases focus on the transfer protons.
by Andrew Yoon 3L
Sun Dec 06, 2020 10:06 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Sapling 5
Replies: 6
Views: 37

Re: Sapling 5

(en) refers to ethylenediamine ligand, or NH2CH2CH2NH2. Ethylenediamine ligand is a bidentate ligand which has a coordination number of 2, and since there are 2 of en, the coordination number would 4. For CO, since there are 2 of it, it will form one ligand each as a monodentate, which will have a c...
by Andrew Yoon 3L
Sun Dec 06, 2020 9:30 pm
Forum: *Molecular Orbital Theory Applied To Transition Metals
Topic: Transition metals
Replies: 11
Views: 200

Re: Transition metals

The transition metals are elements in the d-block, which are groups 3-12. They also have valence electrons in at least two shells.
by Andrew Yoon 3L
Sun Dec 06, 2020 8:05 pm
Forum: Naming
Topic: sapling problem #1
Replies: 5
Views: 45

Re: sapling problem #1

You have most of the name correct. The only parts you have wrong in the name is the chlorine and the cobalt. Since there are 2 Cl anions in the backets, it would be dichloro instead of chloro. For the cobalt, it would be cobalt (III) because of the assigned charge. Since, we don't know the oxidation...
by Andrew Yoon 3L
Fri Nov 27, 2020 7:51 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: ionic liquids
Replies: 7
Views: 86

Re: ionic liquids

An ionic liquid is a salt in a liquid state. It has a low melting point
by Andrew Yoon 3L
Fri Nov 27, 2020 7:48 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: Dipole-Induced-Dipole and Dipole-Dipole
Replies: 10
Views: 96

Re: Dipole-Induced-Dipole and Dipole-Dipole

Dipole-dipole interactions occur when both molecules that are interacting with one another are polar all the time. Dipole-induced-dipole interactions occur when there is a polar molecule interacting with a nonpolar molecule.
by Andrew Yoon 3L
Fri Nov 27, 2020 7:41 pm
Forum: Biological Examples
Topic: Hemoglobin
Replies: 12
Views: 226

Re: Hemoglobin

Both hemoglobins and myoglobins are hemeproteins. However, hemoglobins are found in red blood cells and diffuses oxygen throughout the body. This oxygen goes through the blood and tissues of the body. Myoglobins are found in muscle cells, and they store oxygen in the muscle cells.
by Andrew Yoon 3L
Fri Nov 27, 2020 7:31 pm
Forum: Bronsted Acids & Bases
Topic: Main Difference
Replies: 8
Views: 200

Re: Main Difference

Lewis acid is when accept electrons, while lewis bases donate electrons. Bronsted acids accept hydrogen protons, while Bronsted bases donate hydrogen protons
by Andrew Yoon 3L
Fri Nov 27, 2020 7:28 pm
Forum: Lewis Acids & Bases
Topic: Molecules With Polar Double Bonds
Replies: 5
Views: 50

Re: Molecules With Polar Double Bonds

SO2, is a nonmetal oxide, which makes it a lewis acid. In addition, the shape of the SO2 is bent and it is polar. This causes the oxygen to attract more electrons, making it a lewis acid.
by Andrew Yoon 3L
Sun Nov 22, 2020 1:54 pm
Forum: Bond Lengths & Energies
Topic: Bond Length vs Size of Molecule
Replies: 14
Views: 123

Re: Bond Length vs Size of Molecule

Although bond length definitely affects the strength of the bond, we also have to consider the intermolecular forces. Although both compounds only have LDF's. CCl4 has a higher boiling point than CH4 because it has stronger LDF interacting. This is due to it having more electron shells, which increa...
by Andrew Yoon 3L
Sun Nov 22, 2020 1:46 pm
Forum: Dipole Moments
Topic: Focus Problem 3F.1
Replies: 5
Views: 41

Re: Focus Problem 3F.1

First, I would draw out the lewis structures for all of the compounds. You know all of them have LDP. Next, I would check for hydrogen bonding. That only happens between H and O, N, or F. Dipole-dipole interactions occur when a partially negative part apolar molecule is attracted to a partially posi...
by Andrew Yoon 3L
Sun Nov 22, 2020 1:25 pm
Forum: Bond Lengths & Energies
Topic: electron repulsion
Replies: 15
Views: 122

Re: electron repulsion

Electron repulsion occurs when two of the same sign (negative and negative) come close to each other. They will repulse each other. Yes, electron repulsion does play a part in forming the shape of an atom.
by Andrew Yoon 3L
Sun Nov 22, 2020 1:20 pm
Forum: Electronegativity
Topic: Relationship between Dispersion and Electronegativity
Replies: 6
Views: 30

Re: Relationship between Dispersion and Electronegativity

Dispersion forces are forces between molecules; they hold the two molecules together. They are classified as intermolecular forces. Electronegativity is how often an atom attracts a shared pair of electrons, which connects two atoms together. Electronegativity determines intramolecular forces. Inter...
by Andrew Yoon 3L
Sun Nov 22, 2020 12:53 pm
Forum: Octet Exceptions
Topic: octet rule
Replies: 8
Views: 73

Re: octet rule

Cl has 17 electrons. It has 2 electrons in the first shell, 8 in the second shell, and 7 in the valence shell. The octet rule states that atoms will have 8 electrons in its valence electron. Cl will need one more electron to fill the valence shell and complete the octet rule. So 17 + 1 = 18 electrons.
by Andrew Yoon 3L
Sun Nov 15, 2020 7:29 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 9
Views: 78

Re: Electronegativity

@Maddie Turk

Yes, as the atomic radius increases, the electronegativity decreases. Because the electrons are further and further away from the nucleus of the element, the element becomes less active to attract electrons.
by Andrew Yoon 3L
Sun Nov 15, 2020 7:00 pm
Forum: Resonance Structures
Topic: Formal Charge
Replies: 11
Views: 65

Re: Formal Charge

Yes the more stable molecule/better lewis structure would be when the central atom has a formal charge that is or very close to zero.
by Andrew Yoon 3L
Sun Nov 15, 2020 7:00 pm
Forum: Resonance Structures
Topic: Formal Charge
Replies: 11
Views: 65

Re: Formal Charge

Yes the more stable molecule/better lewis structure would be when the central atom has a formal charge that is or very close to zero.
by Andrew Yoon 3L
Sun Nov 15, 2020 6:46 pm
Forum: Formal Charge and Oxidation Numbers
Topic: 2.A.13
Replies: 5
Views: 48

Re: 2.A.13

The electron that will removed is going to be from the last orbital of the element. Because this electron is furthest from the nucleus, it requires the least amount of energy to be removed. In order to find out which orbital the electron is being removed from, I would write out the electron configur...
by Andrew Yoon 3L
Sun Nov 15, 2020 5:32 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation Number
Replies: 11
Views: 106

Re: Oxidation Number

To find the oxidation number of the example you gave, first you need to set up an equation. Since the final charge of the molecule is given (-1), we can set that equal to the charges of the Cl and O. -1 = (Cl) + 4(O). For O, we can assume it has a -2 charge. So then, we can solve the charge for Cl. ...
by Andrew Yoon 3L
Sun Nov 15, 2020 4:02 pm
Forum: Lewis Structures
Topic: Sapling #4
Replies: 8
Views: 65

Re: Sapling #4

Hi, so for this problem, you have both structures correct. However for structure C, both O's (oxygens) should have a negative charge rather than C (carbon) having a negative charge. N (nitrogen) has the correct charge.
by Andrew Yoon 3L
Sun Nov 08, 2020 11:53 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Parallel electrons
Replies: 7
Views: 53

Re: Parallel electrons

Electrons would be parallel when ground state electrons would fill two or more orbitals before pairing together in the same orbital. This means that the electrons in each orbital would have the same spin rather than when 2 electrons are in the same orbital and when they have opposite spins.
by Andrew Yoon 3L
Sun Nov 08, 2020 11:47 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 7
Views: 23

Re: Ionization Energy

The second ionization energy is greater than the first ionization energy because there are less electrons in the element. With one less electron, the remaining electron(s) will face a greater attraction/pull from the nucleus of the element. In order to remove the second electron that is experiencing...
by Andrew Yoon 3L
Sun Nov 08, 2020 11:42 pm
Forum: Sigma & Pi Bonds
Topic: pi bonds
Replies: 8
Views: 227

Re: pi bonds

Yes, a triple bond is considered one sigma bond and two pi bonds right
by Andrew Yoon 3L
Sun Nov 08, 2020 11:28 pm
Forum: Sigma & Pi Bonds
Topic: Hybridization for p
Replies: 4
Views: 139

Re: Hybridization for p

Pi bonds only have p hybridization and not spx because they can only form with p orbitals.
by Andrew Yoon 3L
Sun Nov 08, 2020 11:26 pm
Forum: Ionic & Covalent Bonds
Topic: Electronegativity
Replies: 16
Views: 90

Re: Electronegativity

Fluorine is the electronegative because it has 7 valence electrons. It only needs one more electron in order for it to have a noble gas configuration (electron octet). Therefore, it easily attracts electron and is highly reactive.
by Andrew Yoon 3L
Sun Nov 01, 2020 12:40 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Equations Coefficient Question
Replies: 15
Views: 108

Re: Balancing Equations Coefficient Question

If your equation has any stoichiometric coefficients that are fractions, you need to convert them to whole numbers. Since you can't have a fraction of a compound, you need to multiply whatever number on one side to the other as well in order for it to be balanced.
by Andrew Yoon 3L
Sun Nov 01, 2020 12:13 pm
Forum: *Shrodinger Equation
Topic: For Ms (spin up, spin down)
Replies: 6
Views: 81

Re: For Ms (spin up, spin down)

For +1/2, I think it is supposed to represent spin up, and -1/2 is supposed to represent spin down.
by Andrew Yoon 3L
Sun Nov 01, 2020 12:00 pm
Forum: Ionic & Covalent Bonds
Topic: Homework due date
Replies: 49
Views: 334

Re: Homework due date

All of the Sapling hw and chem community posts are due at Sunday night at 11:59 pm.
by Andrew Yoon 3L
Sun Nov 01, 2020 11:57 am
Forum: Einstein Equation
Topic: E=pv and E=pc
Replies: 6
Views: 103

Re: E=pv and E=pc

I think that those equations are derived from E = mc^2 and c = (λ)(v, frequency), P = (m)(v, velocity), and E = (h)(v, frequency)
by Andrew Yoon 3L
Sun Nov 01, 2020 1:07 am
Forum: Properties of Light
Topic: Is c always the speed of light?
Replies: 88
Views: 453

Re: Is c always the speed of light?

For now, c will always be equal to the speed of light, which is 3x10^8 m/s.
by Andrew Yoon 3L
Sun Oct 25, 2020 10:16 pm
Forum: Molarity, Solutions, Dilutions
Topic: Stuck on Sapling HW
Replies: 14
Views: 199

Re: Stuck on Sapling HW

The first step is to convert 3.39g of CuNO3 into moles. You can do this using the molar mass of CuNO3. Once you have converted the mass to moles, use the molarity equation (M = n/v) to solve for the volume. Make sure to convert to milliliters.
by Andrew Yoon 3L
Sun Oct 25, 2020 10:08 pm
Forum: DeBroglie Equation
Topic: n1 and n2
Replies: 15
Views: 56

Re: n1 and n2

In this case, n=1 would be the final energy and n=2 would be the initial energy level. In order for it to be less confusing, you can replace n1 and n2 with nfinal and ninitial
by Andrew Yoon 3L
Sun Oct 25, 2020 9:50 pm
Forum: *Black Body Radiation
Topic: Midterm 1
Replies: 15
Views: 271

Re: Midterm 1

No, Black Body radiation will not be on the midterm.
by Andrew Yoon 3L
Sun Oct 25, 2020 9:31 pm
Forum: Properties of Light
Topic: Amplitude
Replies: 9
Views: 64

Re: Amplitude

Amplitude is only used in the wave model. Increasing the amplitude means that there is a higher intensity. Decreasing the amplitude means that there is a lower intensity. With more a higher intensity, the brightness increases and vice versa. In order to change the energy, we have to change the frequ...
by Andrew Yoon 3L
Sun Oct 25, 2020 9:21 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Sapling #19
Replies: 4
Views: 71

Re: Sapling #19

Hi, so for this question, you still use the equation (delta momentum)(delta position) > or equal to (h/4pi). However, for delta momentum, change the mass to helium. In order for helium to match with the units in the equation, first change the molar mass from g/mol to kg/mol. Next, multiply it my Avo...
by Andrew Yoon 3L
Sun Oct 18, 2020 9:58 pm
Forum: SI Units, Unit Conversions
Topic: Metric Conversions
Replies: 9
Views: 117

Re: Metric Conversions

There is an acronym:
King Henry Doesn’t Usually Drink Chocolate Milk

K- kilo
H- hecto
D- deca
U- base unit
D- deci
C- centi
M- milli
by Andrew Yoon 3L
Sun Oct 18, 2020 9:49 pm
Forum: Significant Figures
Topic: How to deal with significant figures in decimals with zeros.
Replies: 20
Views: 194

Re: How to deal with significant figures in decimals with zeros.

Once you have your answer, find the number with the least sig figs, and then apply the number of sig figs in that number to your answer.
by Andrew Yoon 3L
Sun Oct 18, 2020 9:41 pm
Forum: *Shrodinger Equation
Topic: Schrodinger for exam
Replies: 20
Views: 444

Re: Schrodinger for exam

I think the concept an how the equation is used is important for us and for the exam.
by Andrew Yoon 3L
Sun Oct 18, 2020 9:39 pm
Forum: Properties of Light
Topic: Chemistry Community Points
Replies: 10
Views: 85

Re: Chemistry Community Points

Hi! Yes, questions, comments, and replies are all counted as points. You need at least 5 of any of the three by Sunday at 11:59.
by Andrew Yoon 3L
Sun Oct 18, 2020 9:35 pm
Forum: SI Units, Unit Conversions
Topic: Do I need to do very single textbook question on the syllabus?
Replies: 34
Views: 256

Re: Do I need to do very single textbook question on the syllabus?

I would because it just gives you a lot of practice. Doing all the problems, is however, really hard to do.
by Andrew Yoon 3L
Sat Oct 10, 2020 8:40 pm
Forum: Empirical & Molecular Formulas
Topic: Sapling Week 1 #8
Replies: 23
Views: 234

Re: Sapling Week 1 #8

To find the molecular formula, count the number of carbons, hydrogens, and oxygens, respectively. The order of the elements in the molecular should be CHO. Once you have found the number of each element (C6H8O6), you can find find the molecular mass of the compound. The molar mass of carbon, hydroge...
by Andrew Yoon 3L
Sat Oct 10, 2020 8:09 pm
Forum: Balancing Chemical Reactions
Topic: Naming compounds
Replies: 21
Views: 192

Re: Naming compounds

Hi!

Yeah I had the same problem too. What I suggest is to just go over the main chemical formulas (i.e. sulfide, bicarbonate, hydroxide, etc.). Those are kind of the basic formulas, but I don't think we are required to memorize anything more complicated than the examples.

Hope it helps!
by Andrew Yoon 3L
Sat Oct 10, 2020 8:01 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: HW E.15
Replies: 4
Views: 47

Re: HW E.15

The first step that I took to solve this problem was to figure out the mass of M. Since we know the mysterious compound has a molar mass of 74.10 g/mol and the molar mass of (OH)2, we can figure out the molar mass of M by subtracting 34.08 g/mol from 74.10 g/mol. This mass turns out to be 40.08g/mol...
by Andrew Yoon 3L
Sat Oct 10, 2020 5:33 pm
Forum: SI Units, Unit Conversions
Topic: When to convert units?
Replies: 12
Views: 100

Re: When to convert units?

I would only write/convert my final answer to the unit that the question specifies. Also I think that even if the question doesn't ask for a specific, I would keep the answer to a SI unit just to keep it safe.
by Andrew Yoon 3L
Mon Oct 05, 2020 12:22 pm
Forum: Limiting Reactant Calculations
Topic: Week 1 Sapling HW Chem 14A Problem 10
Replies: 10
Views: 198

Re: Week 1 Sapling HW Chem 14A Problem 10

Hello! I was also struggling with this problem. As I was balancing out the equation, I realized that on the product side, there was no magnesium or bromine. So I was wondering how to balance out the equation and figure out that 2-butanone would be the limiting reactant. I mean I understand that sinc...

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