Search found 91 matches

by Brian Nguyen 2I
Sun Feb 28, 2021 11:08 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Diamond vs. Graphite
Replies: 21
Views: 66

Re: Diamond vs. Graphite

Yes, this is possible. But given the high activation energy, it will take a long period of time to form such diamonds, and even so, the diamonds formed will most likely be minuscule in size.
by Brian Nguyen 2I
Sun Feb 28, 2021 11:07 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Instantaneous Rate
Replies: 22
Views: 296

Re: Instantaneous Rate

The instantaneous rate will decrease over time, as there becomes less reactants to be used up.
by Brian Nguyen 2I
Sun Feb 28, 2021 11:05 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Thermodynamics delta G
Replies: 13
Views: 179

Re: Thermodynamics delta G

Delta G of Gibbs' free energy determines whether something is thermodynamically favorable. This is basically spontaneity. A negative delta G is spontaneous.
by Brian Nguyen 2I
Sun Feb 28, 2021 11:05 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Thermodynamics delta G
Replies: 13
Views: 179

Re: Thermodynamics delta G

Delta G of Gibbs' free energy determines whether something is thermodynamically favorable. This is basically spontaneity. A negative delta G is spontaneous.
by Brian Nguyen 2I
Sun Feb 28, 2021 10:32 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode/Cathode
Replies: 45
Views: 82

Re: Anode/Cathode

Yes, the order matters. Always remember that the anode goes on the left while the cathode goes on the right of the diagram.
by Brian Nguyen 2I
Sun Feb 28, 2021 9:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Moles in ΔG = -nFE
Replies: 42
Views: 86

Re: Moles in ΔG = -nFE

When you plug in n, you're plugging in the value of the number of electrons that are transferred in the redox reaction. This means that you use the number of electrons calculated when balancing the reaction itself.
by Brian Nguyen 2I
Sun Feb 21, 2021 5:26 pm
Forum: Balancing Redox Reactions
Topic: Anode and Cathode
Replies: 11
Views: 28

Re: Anode and Cathode

Yes, electrons will always leave from the anode. Losing electrons is oxidation, so this is indeed the oxidized side.
by Brian Nguyen 2I
Sun Feb 21, 2021 5:24 pm
Forum: Balancing Redox Reactions
Topic: Cell/battery
Replies: 26
Views: 76

Re: Cell/battery

Yes, these should be the same and you can use them interchangeably.
by Brian Nguyen 2I
Sun Feb 21, 2021 5:22 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Comparing Molar Entropies of Different Compounds
Replies: 9
Views: 38

Re: Comparing Molar Entropies of Different Compounds

Yes, larger molecules have more complexity and thus have more entropy. Also, gases will have more entropy than liquids, and liquids will have more entropy than solids. Solids have the least entropy out of the phases.
by Brian Nguyen 2I
Sun Feb 21, 2021 5:10 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Textbook 4F.17
Replies: 4
Views: 15

Re: Textbook 4F.17

Entropy is a state function, thus meaning that it doesn't matter which path is taken. You're asked to calculate the entropy of vaporization at 85 degrees, but you only are given the entropy values at 100 degrees, so you must create a path where 85 degrees is the start and end point. This is why you ...
by Brian Nguyen 2I
Sun Feb 21, 2021 5:00 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Thermodynamically Favorable
Replies: 27
Views: 65

Re: Thermodynamically Favorable

Thermodynamically favorable is when the reaction is spontaneous, which would thus mean that the Gibbs' free energy is negative. When the Gibbs' free energy is positive, the reaction is nonspontaneous and thus thermodynamically unfavorable.
by Brian Nguyen 2I
Sat Feb 13, 2021 12:28 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Equations
Replies: 8
Views: 41

Re: Equations

We won't have to use the integral equations. The integrals were just used as a way to prove the equations we have to memorize in class for entropy, such as deltaS= nCv(lnT2/T1) or deltaS = nR(lnV2/V1). Those equations are just for you to understand conceptually why we use the equations we use.
by Brian Nguyen 2I
Sat Feb 13, 2021 12:26 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: R constants
Replies: 40
Views: 882

Re: R constants

Try to remember the units of R in order to solve. Look at the context of the situation by looking at the units in the equation you're trying to solve, and make sure that the R you use properly cancels out the units.
by Brian Nguyen 2I
Sat Feb 13, 2021 12:24 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Low temp making DeltaG negative?
Replies: 8
Views: 27

Re: Low temp making DeltaG negative?

This cannot occur. You cannot have a negative delta G. By taking a look at the equation ∆G = ∆H-T∆S, a negative entropy or deltaS will cancel out the minus sign in the equation, thus making T∆S a positive value. This positive value added with a positive enthalpy or positive delta H will give you a p...
by Brian Nguyen 2I
Sat Feb 13, 2021 12:22 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous as Written
Replies: 10
Views: 27

Re: Spontaneous as Written

Yes, that's correct. If delta G is negative, then the reaction is always considered spontaneous.
by Brian Nguyen 2I
Sat Feb 13, 2021 12:15 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: deltaS equations
Replies: 8
Views: 37

Re: deltaS equations

deltaS = q/T is used for when temperature is constant. deltaS = nR*ln(V2/V1), we use when there is a change in volume. Temperature is constant here. deltaS = nC*ln(T2/T1) is when temperature changes. C values are used depending on whether pressure or volume is constant. Cp is used when pressure is c...
by Brian Nguyen 2I
Sun Feb 07, 2021 6:44 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Cp and Cv
Replies: 7
Views: 47

Re: Cp and Cv

Cp will be greater than Cv. Usually, the equation used will be Cp = Cv + R.
by Brian Nguyen 2I
Sun Feb 07, 2021 6:40 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy definition
Replies: 27
Views: 74

Re: Entropy definition

Entropy is how much disorder there is in a system. A positive entropy means there is more disorder, whereas negative means that there is less. The equation for entropy is S = kB(lnW).
by Brian Nguyen 2I
Sun Feb 07, 2021 6:37 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: converting T to kelvin
Replies: 46
Views: 483

Re: converting T to kelvin

It depends on what the kind of T is used. If it is delta T, it won't make a difference between Celsius and Kelvin. Since Kelvin is converted by adding 273.15 to the Celsius measurement, either unit does not matter with change in temperature. It only matters when it is T by itself. With just T, eithe...
by Brian Nguyen 2I
Sun Feb 07, 2021 5:59 pm
Forum: Calculating Work of Expansion
Topic: Reversible vs. Irreversible
Replies: 4
Views: 23

Re: Reversible vs. Irreversible

Reversible reactions will stay in equilibrium, whereas irreversible reactions do not stay at equilibrium with the surroundings. Pressure is constant with irreversible reactions, hence the reason why one simply multiplies the negative pressure by the change in volume (-P x delta V) to calculate work....
by Brian Nguyen 2I
Sun Feb 07, 2021 5:48 pm
Forum: Calculating Work of Expansion
Topic: Work on the surroundings
Replies: 4
Views: 18

Re: Work on the surroundings

Systems will perform work on the surroundings when the work is negative. Work is performed on the system when work is positive.
by Brian Nguyen 2I
Sun Jan 31, 2021 8:50 pm
Forum: Phase Changes & Related Calculations
Topic: Salt
Replies: 19
Views: 49

Re: Salt

Salts are acidic if they contain a weak base anion and strong acid cation. They are basic if they contain a strong base anion and weak acid cation. They are neutral if they have a cation from a strong acid and an anion from a strong base.
by Brian Nguyen 2I
Sun Jan 31, 2021 8:49 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Focus 4.31
Replies: 8
Views: 29

Re: Textbook Focus 4.31

To solve the problem, you use the equation PV=nRT and solve plugging in what's given to you in the equation. As for the pressure, you just need to remember that 760 torr is equivalent to 1 atm. The R value can be found on the equation sheet we're given. From here, you can solve the equation.
by Brian Nguyen 2I
Sun Jan 31, 2021 8:36 pm
Forum: Phase Changes & Related Calculations
Topic: Examples of sublimation
Replies: 12
Views: 92

Re: Examples of sublimation

Other examples can include snow and ice. I also found online that iodine will sublime from solid to purple gas at 100 degrees Celsius. It also says that moth balls can also sublime.
by Brian Nguyen 2I
Sun Jan 31, 2021 8:33 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Neutralization
Replies: 25
Views: 105

Re: Neutralization

Neutralization is just when an acid and base react to each other. In this case, the acid would be HCl and the base would be NaOH. These two react to form a salt and water. In this case, H2O and NaCl is formed.
by Brian Nguyen 2I
Sun Jan 31, 2021 8:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Diatomic molecules standard enthalpy of formation
Replies: 22
Views: 112

Re: Diatomic molecules standard enthalpy of formation

Yes, I would assume that these diatomic molecules are in their most stable state. Thus, the enthalpy would be zero.
by Brian Nguyen 2I
Sun Jan 24, 2021 7:56 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Diatomic Molecules
Replies: 6
Views: 52

Re: Diatomic Molecules

A molecule is considered diatomic so long that there are two atoms involved. O2, Br2, H2, etc are considered diatomic elements, since there are two atoms of the same element in a molecule.
by Brian Nguyen 2I
Sun Jan 24, 2021 7:45 am
Forum: Phase Changes & Related Calculations
Topic: State Property
Replies: 46
Views: 161

Re: State Property

State properties mean that you only need to focus on the final and initial values. In this case, for enthalpy, it is a state property since enthalpy is only calculated using the initial heat and final heat values.
by Brian Nguyen 2I
Sun Jan 24, 2021 7:41 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Exothermic and Endothermic Reactions
Replies: 9
Views: 36

Re: Exothermic and Endothermic Reactions

Catalysts will lower the activation energy of a reaction. This does not affect the change in enthalpy, as enthalpy is a state reaction. Thus, this does not affect whether a reaction is exothermic and endothermic, which can be indicated from the change in enthalpy.
by Brian Nguyen 2I
Sun Jan 24, 2021 7:34 am
Forum: Phase Changes & Related Calculations
Topic: Endothermic v. Exothermic
Replies: 107
Views: 341

Re: Endothermic v. Exothermic

Yes, this is definitely true. Exothermic reactions are always labeled by a negative delta H, whereas endothermic reactions are always labeled by a positive delta H. This is due to how exothermic reactions release heat, whereas endothermic reactions absorb heat.
by Brian Nguyen 2I
Sun Jan 24, 2021 7:31 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Direction of arrows
Replies: 11
Views: 40

Re: Direction of arrows

If there's just one arrow, it means that the reaction usually proceeds in that direction most of the time. It doesn't necessarily mean that it will proceed only in that way, but just probably that for the majority of the time, it proceeds in such direction.
by Brian Nguyen 2I
Sun Jan 17, 2021 7:35 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure Increase
Replies: 7
Views: 19

Re: Pressure Increase

If the pressure increase did nothing to shift the reaction, chances are this is because the gas involved was an inert gases. Pressure increases and decreases can change concentrations in reactions, which shifts the reaction, but inert gases will not change volume. Thus, there is no change to concent...
by Brian Nguyen 2I
Sun Jan 17, 2021 7:29 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Ka and Kb
Replies: 5
Views: 40

Re: Ka and Kb

Ka and Kb added together make Kw, which is always 1.0 times 10^14. Thus, as Kw always remains the same, as Ka increases, Kb will also decrease at the same time. This is also applied vice versa.
by Brian Nguyen 2I
Sun Jan 17, 2021 7:19 pm
Forum: Ideal Gases
Topic: reversing reactions
Replies: 83
Views: 461

Re: reversing reactions

When you reverse a reaction, K is just equal to the reciprocal of K instead. This is 1 divided by K.
by Brian Nguyen 2I
Sun Jan 17, 2021 7:18 pm
Forum: Ideal Gases
Topic: Ice method
Replies: 14
Views: 73

Re: Ice method

To use the ICE method, you have to know what ICE stands for. I stands for initial, C stands for change, and E stands for equilibrium. Using this method means you are trying to solve for E. First, you have to balance the equation given. Then for I, write out the initial concentrations given in the pr...
by Brian Nguyen 2I
Sun Jan 17, 2021 7:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ice Box Method
Replies: 14
Views: 95

Re: Ice Box Method

Whenever something is being produced, you use a positive sign for what is being made. For what we use to get to that end point, we use a negative sign. For example, if there is a shift to the right in the reaction, for the products you will use an add sign. You will use the subtract sign on the reac...
by Brian Nguyen 2I
Sun Jan 10, 2021 10:06 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O
Replies: 44
Views: 334

Re: H2O

H2O is not included because solids and liquids are not included in equilibrium equations. The only exception would be if H2O was a gas.
by Brian Nguyen 2I
Sun Jan 10, 2021 8:46 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Change inn temperature
Replies: 6
Views: 40

Re: Change inn temperature

K is affected by temperature based on whether the reaction is exothermic and endothermic. The reaction will favor product formation if the reaction is endothermic. The reaction will favor reactant formation is the reaction is exothermic.
by Brian Nguyen 2I
Sun Jan 10, 2021 7:02 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing pressure
Replies: 7
Views: 43

Re: Changing pressure

As long as the gas isn't inert, then changing the pressure will change the reaction due to a change in volume. The change in volume changes the concentration of the products and reactants, which thus causes a reaction change.
by Brian Nguyen 2I
Sun Jan 10, 2021 6:46 pm
Forum: Ideal Gases
Topic: Units for Pressure
Replies: 41
Views: 850

Re: Units for Pressure

Don't convert to pascals. We use atm or barr in these problems involving pressure, so there is no need for conversion.
by Brian Nguyen 2I
Sun Jan 10, 2021 6:37 pm
Forum: Ideal Gases
Topic: Advice on how to navigate Chem Community
Replies: 17
Views: 110

Re: Advice on how to navigate Chem Community

When I use this website, I usually just scroll down to the topics on the home page and find the topic that we learned about for the week. Then I answer questions under certain posts. I usually use quick links a lot because it helps me check to see how many posts I've made so far. Sometimes, if you w...
by Brian Nguyen 2I
Thu Dec 17, 2020 3:31 am
Forum: Lewis Acids & Bases
Topic: Lewis vs Bronsted
Replies: 20
Views: 115

Re: Lewis vs Bronsted

The Bronsted definition involves protons, where as the Lewis definition involves electron pairs. Lewis acids are electron pairs acceptors, whereas Lewis bases are electron pair donors. Bronsted acids are proton donors, whereas Bronsted bases are proton acceptors.
by Brian Nguyen 2I
Thu Dec 17, 2020 3:13 am
Forum: Naming
Topic: oxidation number
Replies: 8
Views: 76

Re: oxidation number

To find the oxidation number, I just take the overall charge of the compound and then take into account the charges of other elements or compounds within the cation to find the charge of the metal ion.
by Brian Nguyen 2I
Thu Dec 17, 2020 2:49 am
Forum: General Science Questions
Topic: Study Habits
Replies: 16
Views: 81

Re: Study Habits

Honestly, I just like to focus on solely textbook problems. The more practice I get, the more confident I feel about topics, since most of the exam questions are structured like the textbook problems.
by Brian Nguyen 2I
Thu Dec 17, 2020 2:41 am
Forum: General Science Questions
Topic: 14B enrollment
Replies: 9
Views: 135

Re: 14B enrollment

Most of the concepts that we go over in 14A will be applied in 14B. This is probably especially seen with the material we covered with acids and bases, since we only touched on the surface of this subject before the final.
by Brian Nguyen 2I
Thu Dec 17, 2020 2:06 am
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 187
Views: 109117

Re: Reading the textbook [ENDORSED]

Reading the textbook is just helpful if I find that I need to find other ways to understand the material if lectures confuse me. Generally, the textbook is most useful as a source of practice, since I mainly do practice problems from there. The more practice problems I do, the more prepared I am for...
by Brian Nguyen 2I
Sun Dec 06, 2020 9:48 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: tetradentate
Replies: 8
Views: 73

Re: tetradentate

Dentate indicates that there is a binding site. The prefix indicates how many binding sites there are. For example, bidentate means there are two binding sites. In your case, tetradentate would have four binding sites.
by Brian Nguyen 2I
Sun Dec 06, 2020 9:45 pm
Forum: Naming
Topic: Order of Ligands/naming
Replies: 28
Views: 147

Re: Order of Ligands/naming

You order based on the actual ligand name, not by prefix. Let's say we had tetraammine and dichloro. Dichloro would not go before tetraammine because ammine comes before chloro alphabetically.
by Brian Nguyen 2I
Sun Dec 06, 2020 9:43 pm
Forum: Naming
Topic: Sapling 1
Replies: 34
Views: 182

Re: Sapling 1

It's based on chloro and ammine. Thus, tetraammine would go first and then dichloro.
by Brian Nguyen 2I
Sun Dec 06, 2020 9:39 pm
Forum: Naming
Topic: Ferrate
Replies: 5
Views: 42

Re: Ferrate

From what I remember silver and gold are some exceptions. However, I remember someone asked my TA if we were required to know any exceptions, and she said that you probably wouldn't have to remember them except probably the one for iron.
by Brian Nguyen 2I
Sun Dec 06, 2020 9:26 pm
Forum: Naming
Topic: Naming in alphabetical order?
Replies: 10
Views: 71

Re: Naming in alphabetical order?

You name the ligands in alphabetical order. The prefixes are not taken into account when u order the ligands in alphabetical order. The ligand name is listed before the metal cation.
by Brian Nguyen 2I
Sun Nov 29, 2020 5:13 pm
Forum: Bond Lengths & Energies
Topic: Boiling vs. Melting Point
Replies: 15
Views: 106

Re: Boiling vs. Melting Point

Boiling point is the point at which a liquid turns into a gas. Melting point is the point at which a solid turns into a liquid. The more intermolecular forces that are present, the higher the boiling and melting points of a substance will be.
by Brian Nguyen 2I
Sun Nov 29, 2020 5:05 pm
Forum: Dipole Moments
Topic: H-Bonds
Replies: 14
Views: 131

Re: H-Bonds

Yes, it does happen when you have another compound with a lone pair of electrons. However, you also have to keep in mind that these form when the other compound has a hydrogen bonded to a fluorine, oxygen, or nitrogen atom.
by Brian Nguyen 2I
Sun Nov 29, 2020 4:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar/non-polar bonds vs molecules
Replies: 5
Views: 33

Re: Polar/non-polar bonds vs molecules

Polar bonds are formed based on if there is a notable difference in electronegativity between two elements within a molecule. Polar molecules are formed when the dipole moments formed due to polar bonds don't cancel out. If they do cancel out, then these molecules are nonpolar.
by Brian Nguyen 2I
Sun Nov 29, 2020 4:40 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 Dispersion
Replies: 33
Views: 182

Re: London Dispersion

Yes, London dispersion forces are always present. However, these forces are only significantly strong the larger the mass of the molecule.
by Brian Nguyen 2I
Sun Nov 29, 2020 3:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar vs non-polar
Replies: 7
Views: 62

Re: polar vs non-polar

Just look at the electronegativity. If there's a notable difference between the two electronegativities, then the bond is polar. If there isn't a notable difference, then the bond is non-polar.
by Brian Nguyen 2I
Sun Nov 22, 2020 9:56 pm
Forum: Resonance Structures
Topic: Resonance Structures and Energy
Replies: 21
Views: 147

Re: Resonance Structures and Energy

Yes, they prefer the resonance structure with the lowest energy. This would be mean the formal charges are closest to zero on the atom.
by Brian Nguyen 2I
Sun Nov 22, 2020 9:55 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 30
Views: 165

Re: Polarity

You can have a nonpolar molecule even if there are polar bonds due to the fact that the dipoles formed from polar bonds are cancelled out from the overall shape of the molecule.
by Brian Nguyen 2I
Sun Nov 22, 2020 9:45 pm
Forum: Dipole Moments
Topic: Boiling/Melting Points
Replies: 15
Views: 142

Re: Boiling/Melting Points

Higher boiling and melting points are indicated by if there are stronger intermolecular forces present. For example, if u have a molecule with dipole-dipole forces and London dispersion forces and a molecule with only London dispersion forces, then the molecule that has dipole-dipole forces has a hi...
by Brian Nguyen 2I
Sun Nov 22, 2020 9:32 pm
Forum: Octet Exceptions
Topic: Identifying Radicals
Replies: 24
Views: 197

Re: Identifying Radicals

You can identify a radical when there is the presence of a lone unpaired electron. One example is CH3.
by Brian Nguyen 2I
Sun Nov 22, 2020 5:17 pm
Forum: Coordinate Covalent Bonds
Topic: Hydrogen bonds
Replies: 19
Views: 175

Re: Hydrogen bonds

Carbon and hydrogen's electronegativity difference is too small compared to that of hydrogen with the elements nitrogen, oxygen, and fluorine. Thus, it can't form partial charges for hydrogen bonds to occur.
by Brian Nguyen 2I
Fri Nov 13, 2020 5:41 pm
Forum: Bond Lengths & Energies
Topic: reactive
Replies: 10
Views: 84

Re: reactive

Double bonds are stronger than single bonds. Thus, they are more stable than single bonds and less reactive than single bonds.
by Brian Nguyen 2I
Fri Nov 13, 2020 5:39 pm
Forum: Electronegativity
Topic: Finding electronegativity values
Replies: 6
Views: 43

Re: Finding electronegativity values

I don't think you have to memorize the actual values. It just matters if you know what the electronegativity trend is, as we've been taught in lecture.
by Brian Nguyen 2I
Fri Nov 13, 2020 5:38 pm
Forum: Electronegativity
Topic: Fluorine and Helium
Replies: 6
Views: 48

Re: Fluorine and Helium

Usually when it comes to helium, it's a noble gas, so we don't need to worry about it in terms of electronegativity. It has a filled outer energy level. It fulfills the duet rule.
by Brian Nguyen 2I
Fri Nov 13, 2020 5:32 pm
Forum: Lewis Structures
Topic: Chemical Names
Replies: 9
Views: 63

Re: Chemical Names

I doubt that you will need to remember nomenclature. Lavelle focuses on mainly how well you know how to problem solve, so you shouldn't have to worry about nomenclature.
by Brian Nguyen 2I
Fri Nov 13, 2020 5:22 pm
Forum: Resonance Structures
Topic: Resonance Hybrid Structures
Replies: 6
Views: 35

Re: Resonance Hybrid Structures

The test will be multiple choice for the midterm, so I doubt that we'll have to draw them out. If anything, we'll be given pictures of it on questions, but you probably won't be expected to draw them.
by Brian Nguyen 2I
Sun Nov 08, 2020 10:52 pm
Forum: Ionic & Covalent Bonds
Topic: Atomic Radius
Replies: 38
Views: 260

Re: Atomic Radius

It decreases as you move across a period because the atomic number increases. When the atomic number increases, the amount of protons increase. There is more of a positive charge present, increasing the attraction between the electrons and protons, thus decreasing the space between the electrons and...
by Brian Nguyen 2I
Sun Nov 08, 2020 10:51 pm
Forum: DeBroglie Equation
Topic: Conversions
Replies: 9
Views: 94

Re: Conversions

Metric conversions should be memorized. However, when it comes to any other conversions, they should be given on the test.
by Brian Nguyen 2I
Sun Nov 08, 2020 10:40 pm
Forum: Photoelectric Effect
Topic: Participation points
Replies: 16
Views: 179

Re: Participation points

You have to post five times per week, since they check the time when there's a post. You can check your posts in quick links to see how many you have.
by Brian Nguyen 2I
Sun Nov 08, 2020 10:19 pm
Forum: Trends in The Periodic Table
Topic: Elements that form Cations
Replies: 6
Views: 25

Re: Elements that form Cations

The elements on the left side of the periodic table are more likely to form cations due to the fact they have a small number of valence electrons. The smaller the number, the more likely you are to lose an electron instead of gain one.
by Brian Nguyen 2I
Sun Nov 08, 2020 10:12 pm
Forum: Trends in The Periodic Table
Topic: memorizing trends
Replies: 14
Views: 59

Re: memorizing trends

I usually just print out a periodic table and label it based on where the trends are. It helps for me to see it visually all in one place in order to memorize it.
by Brian Nguyen 2I
Sun Nov 01, 2020 8:25 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Chem Community Posts
Replies: 10
Views: 65

Re: Chem Community Posts

I'm pretty sure that as long as you post something, it counts. As long as it is any interaction, your post should be counted as a point.
by Brian Nguyen 2I
Sun Nov 01, 2020 8:24 pm
Forum: Photoelectric Effect
Topic: Chapter Readings for the 2nd Midterm
Replies: 6
Views: 75

Re: Chapter Readings for the 2nd Midterm

In my opinion, it will probably cover material starting from where we left off after we took Midterm 1 up until Focus 9 if I had to guess. I don't think it'll be a cumulative test, but there's probably bound to be mention of old topics at some point since most topics that we learn probably overlap w...
by Brian Nguyen 2I
Sun Nov 01, 2020 7:13 pm
Forum: Quantum Numbers and The H-Atom
Topic: Spin state
Replies: 25
Views: 222

Re: Spin state

The spin state does not exactly mean that an electron points "up" or "down" but it differentiates between two different states itself. This can be labeled as a +1/2 or -1/2.
by Brian Nguyen 2I
Sun Nov 01, 2020 7:11 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Sapling #24
Replies: 16
Views: 74

Re: Sapling #24

I initially had trouble with this question too. Some of the waves look continuous, but you need to check to make sure that the ends of each wave will meet perfectly. That's how you can differentiate between which waves are according to the model and which are not.
by Brian Nguyen 2I
Sun Nov 01, 2020 7:05 pm
Forum: *Shrodinger Equation
Topic: Midterm Scores
Replies: 30
Views: 342

Re: Midterm Scores

I heard that they're waiting until everyone has finished taking the exam. The last exam should've been taken on Friday, so anytime soon probably the scores will be up. You can probably check through CCLE to see your score soon.
by Brian Nguyen 2I
Sun Oct 25, 2020 5:04 pm
Forum: DeBroglie Equation
Topic: 1B.21 Conversion Question
Replies: 3
Views: 56

Re: 1B.21 Conversion Question

I feel like you would have to know that conversion beforehand. However, I feel like we won't have to necessarily remember that kind of stuff for our upcoming midterm, so you probably don't have to worry about those kind of conversions.
by Brian Nguyen 2I
Sun Oct 25, 2020 5:02 pm
Forum: Einstein Equation
Topic: Scratch paper during the exam
Replies: 19
Views: 155

Re: Scratch paper during the exam

Yes, I think you should be fine if you have some scratch paper as long as it is visibly blank, but I would check with the TA first just to be safe.
by Brian Nguyen 2I
Sun Oct 25, 2020 4:56 pm
Forum: Photoelectric Effect
Topic: Intensity vs. Frequency
Replies: 22
Views: 146

Re: Intensity vs. Frequency

Intensity relates to amount of photons, whereas frequency relates to the quality of a photon. Frequency is the number of cycles per second.
by Brian Nguyen 2I
Sun Oct 25, 2020 4:35 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Amplitude
Replies: 16
Views: 85

Re: Amplitude

Increasing amplitude doesn't have a correlation with the wavelength and frequency. However, it is important to note that the wavelength will decrease when frequency increases, and vice versa.
by Brian Nguyen 2I
Sun Oct 25, 2020 4:02 pm
Forum: Photoelectric Effect
Topic: Mass of atoms
Replies: 18
Views: 105

Re: Mass of atoms

Kilograms is the SI Unit for mass, so you will have to keep in mind that when solving, your mass is converted in kilograms in order to get the right calculation.
by Brian Nguyen 2I
Sun Oct 18, 2020 6:09 pm
Forum: Properties of Light
Topic: Study Advice
Replies: 50
Views: 308

Re: Study Advice

I would try the practice problems in the textbook first, and then seek help at a step up session if you find yourself struggling to complete the practice problems. I hear that the step up sessions really help, so honestly it doesn't help to do both just for the extra practice.
by Brian Nguyen 2I
Sun Oct 18, 2020 6:06 pm
Forum: Properties of Light
Topic: Photoelectric spectrum
Replies: 24
Views: 190

Re: Photoelectric spectrum

I think it's just necessary that you know where things generally are on the spectrum. It might be helpful to keep in mind where visible light is on the spectrum (400-700 nm). You don't have to memorize the exact wavelengths, but it's necessary to know which has low and which has high frequency when ...
by Brian Nguyen 2I
Sun Oct 18, 2020 6:04 pm
Forum: Properties of Electrons
Topic: Combining Equations
Replies: 10
Views: 98

Re: Combining Equations

You need to use substitution in order to acquire this equation. You can solve for v in E = λv to get v = E/λ. Then you can substitute the v in E = hv to get E = hc/λ.
by Brian Nguyen 2I
Sun Oct 18, 2020 6:00 pm
Forum: Properties of Light
Topic: Word Problems
Replies: 7
Views: 34

Re: Word Problems

Usually you just look for whether it states in the problem itself. I also pay attention to units, so if they ask for Hertz, the problem is asking for frequency. If the problem asks for nanometers, they are looking for wavelength.
by Brian Nguyen 2I
Sat Oct 17, 2020 12:49 pm
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 203
Views: 1402

Re: How are you studying?

I try to make sure I take advantage of all the resources given. I watch all the modules and lectures and take notes. Then I try to divide evenly time to read the textbook and finish all the practice problems. It also helps for me to look at the the key concepts and try to write them on flashcards fo...
by Brian Nguyen 2I
Sat Oct 10, 2020 10:49 pm
Forum: SI Units, Unit Conversions
Topic: Unit Rounding
Replies: 11
Views: 79

Re: Unit Rounding

I always just don't think of rounding until I get to the answer that I solve for. Once I reach that point, I use significant figures to figure out where to round. I always just remember that leading zeros don't count and trailing zeros do count if there is a decimal present in the number when determ...
by Brian Nguyen 2I
Sat Oct 10, 2020 3:19 pm
Forum: Limiting Reactant Calculations
Topic: Best way to find limiting reactant
Replies: 5
Views: 97

Re: Best way to find limiting reactant

Hi! For me, it's just much easier for me to visualize which reactant is limiting using the first method. It is up to preference, but I just find the first method easier to understand since it shows exactly which reactant I will end up with excess.
by Brian Nguyen 2I
Wed Oct 07, 2020 6:37 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Chemical Formulas of Compounds
Replies: 9
Views: 139

Re: Chemical Formulas of Compounds

I think after practicing a lot of problems, you start to pick up on the formulas of certain compounds, but typically as many people have said, you just need to focus on how to solve a problem. As long as you're good with the concepts taught in class and how to apply them, you should be fine.
by Brian Nguyen 2I
Wed Oct 07, 2020 6:25 pm
Forum: Balancing Chemical Reactions
Topic: Periodic Table
Replies: 50
Views: 488

Re: Periodic Table

I think it's just helpful in general to be able to know at least what the symbols for commonly used elements are, but we will definitely be able to use a periodic table. It just helps to know certain symbols and basic molar masses for sake of time during an assessment.
by Brian Nguyen 2I
Wed Oct 07, 2020 6:19 pm
Forum: Limiting Reactant Calculations
Topic: Actual and Theoretical yields
Replies: 14
Views: 145

Re: Actual and Theoretical yields

Another question regarding this, will the actual yield always be given when asking to calculate percentage yield? Hi, I would assume that the actual yield would always be given, since we can only calculate theoretical yield on our own. You can't calculate the actual yield; you'd have to be given it...

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