Search found 84 matches

by Nuoya Jiang
Sat Feb 22, 2020 10:32 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 8
Views: 21

Re: Galvanic Cells

It uses chemical energy in redox reactions to produce electricity.
by Nuoya Jiang
Sat Feb 22, 2020 10:29 am
Forum: Balancing Redox Reactions
Topic: Charge of oxygen
Replies: 15
Views: 41

Re: Charge of oxygen

The oxidation number of oxygen would probably always be 2.
by Nuoya Jiang
Sat Feb 22, 2020 10:28 am
Forum: Identifying Acidic & Basic Salts
Topic: Midterm 3C
Replies: 6
Views: 28

Re: Midterm 3C

Yes, because when it dissolves, the NH4+ ions in water can donate a proton, so it can lower the pH.
by Nuoya Jiang
Sat Feb 22, 2020 10:24 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding Inert Gas
Replies: 18
Views: 45

Re: Adding Inert Gas

It has no effect because adding an inert gas would not change the concentration/partial pressure of the reactants and products.
by Nuoya Jiang
Sat Feb 15, 2020 3:56 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: P1/P2
Replies: 10
Views: 49

Re: P1/P2

Because in the ideal gas law, P and V are inversely proportionate to each other.
by Nuoya Jiang
Sat Feb 15, 2020 3:53 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G and spontaneity
Replies: 4
Views: 23

Re: Delta G and spontaneity

Yes, because when delta G is negative, it tends to release energy when proceeding to the products, and vice versa.
by Nuoya Jiang
Sat Feb 15, 2020 3:51 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Meaning of q=-w
Replies: 11
Views: 60

Re: Meaning of q=-w

Usually, in an isothermally reversible gas expansion, the work done by the heat equals the heat it received.
by Nuoya Jiang
Sat Feb 15, 2020 3:50 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpies of Formation
Replies: 10
Views: 22

Re: Standard Enthalpies of Formation

delta H naught is 0 when the element is in its most stable form.
by Nuoya Jiang
Sat Feb 15, 2020 3:49 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Joules or KJ?
Replies: 14
Views: 39

Re: Joules or KJ?

Most of the time J.
by Nuoya Jiang
Sat Feb 08, 2020 11:59 am
Forum: General Science Questions
Topic: Midterm
Replies: 17
Views: 154

Re: Midterm

The pizza rolls review sheet can be super helpful.
by Nuoya Jiang
Sat Feb 08, 2020 11:56 am
Forum: Ideal Gases
Topic: Temperature
Replies: 17
Views: 46

Re: Temperature

Most of the time yes, because you have to cancel the units in the gas constant R. But when you are calculation the difference between temperatures, for example, in the equation involving heat capacity, you don't have to worry about that.
by Nuoya Jiang
Sat Feb 08, 2020 11:53 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Spontaneous vs Nonspontaneous
Replies: 4
Views: 17

Re: Spontaneous vs Nonspontaneous

It depends on the sign of delta G. If delta G is negative, the forward reaction can occur spontaneously.
by Nuoya Jiang
Sat Feb 08, 2020 11:48 am
Forum: Phase Changes & Related Calculations
Topic: Enthalpy of a combustion reaction?
Replies: 7
Views: 22

Re: Enthalpy of a combustion reaction?

It is usually negative because heat is released during the combustion process.
by Nuoya Jiang
Sat Feb 08, 2020 11:47 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Closed Systems
Replies: 13
Views: 35

Re: Closed Systems

Probably temperature, volume, and pressure since we can only change the "energy" part of the system.
by Nuoya Jiang
Sat Feb 01, 2020 3:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Discussion
Replies: 8
Views: 45

Re: Discussion

No, but we have to hand in the homework. The practise questions in the discussion are usually helpful.
by Nuoya Jiang
Sat Feb 01, 2020 3:35 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated vs Closed [ENDORSED]
Replies: 34
Views: 125

Re: Isolated vs Closed [ENDORSED]

Yes, it is isolated in an ideal situation because we can neither exchange substance nor energy with the surrounding.
by Nuoya Jiang
Sat Feb 01, 2020 3:29 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Material
Replies: 13
Views: 64

Re: Midterm Material

There is a review sheet and some sessions provided by the UAs, which is super useful for midterms and finals.
by Nuoya Jiang
Sat Feb 01, 2020 3:27 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reaction enthalpy
Replies: 14
Views: 41

Re: reaction enthalpy

It requires energy to break a bond, so the change in energy should be positive. When a bond form, the system indeed goes more stable, with less energy, so it releases energy, and the enthalpy should be negative.
by Nuoya Jiang
Sat Feb 01, 2020 3:24 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes
Replies: 17
Views: 43

Re: Phase Changes

Yes, during phase change, the temperature remains constant, but latent heat is released or absorbed.
by Nuoya Jiang
Sat Jan 25, 2020 3:56 pm
Forum: Phase Changes & Related Calculations
Topic: Heat vs. Enthalpy
Replies: 6
Views: 22

Re: Heat vs. Enthalpy

Enthalpy is the change of heat in a chemical reaction, while heat is a more general term.
by Nuoya Jiang
Sat Jan 25, 2020 3:53 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: sign changes in bond enthalpy
Replies: 5
Views: 18

Re: sign changes in bond enthalpy

Energy is required when we break a bond, so the sign should be positive. When bonds form, it releases energy, and so the sign should be negative.
by Nuoya Jiang
Sat Jan 25, 2020 3:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Percent Ionization
Replies: 12
Views: 41

Re: Percent Ionization

It should be the final ionized acid/base divided by the initial concentration of the acid/base.
by Nuoya Jiang
Sat Jan 25, 2020 3:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Grading of Tests
Replies: 18
Views: 92

Re: Grading of Tests

Yes, we can get partial credit.
by Nuoya Jiang
Sat Jan 25, 2020 3:19 pm
Forum: Phase Changes & Related Calculations
Topic: Steam Burn
Replies: 6
Views: 31

Re: Steam Burn

When the steam hits your art, it releases its latent heat because it is changing its phase from a gas to a liquid.
by Nuoya Jiang
Sun Jan 19, 2020 10:26 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Quadratic Equation
Replies: 8
Views: 24

Re: Quadratic Equation

When the equilibrium constant is 10^-3 or greater, we should use the quadratic equation.
by Nuoya Jiang
Sun Jan 19, 2020 10:23 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE Tables
Replies: 13
Views: 35

Re: ICE Tables

Is it the same reason that we do not include it when we are calculating the equilibrium constant?
by Nuoya Jiang
Sun Jan 19, 2020 10:20 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q < K
Replies: 16
Views: 43

Re: Q < K

Yes, it is. The product side is favoured.
by Nuoya Jiang
Sun Jan 19, 2020 10:19 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pKa
Replies: 13
Views: 23

Re: pKa

The stronger an acid, the smaller the pka.
by Nuoya Jiang
Sun Jan 19, 2020 10:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Q
Replies: 14
Views: 31

Re: K vs Q

k is a constant and is used as a standard that we can compare with. Q is what we can calculate based on the data we've got.
by Nuoya Jiang
Sat Jan 11, 2020 2:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Change in k
Replies: 11
Views: 42

Re: Change in k

K is a constant and if anything of the environment changes, such as the temperature, the system adjusts to the changes, resulting in the constant k.
by Nuoya Jiang
Sat Jan 11, 2020 2:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Table 5G.2
Replies: 5
Views: 31

Re: Table 5G.2

We can use the Kc in this table if the question asks us to solve for concentrations of gases in the reaction, such as question 5.39.
by Nuoya Jiang
Sat Jan 11, 2020 2:45 pm
Forum: Ideal Gases
Topic: Topics on Test 1
Replies: 37
Views: 175

Re: Topics on Test 1

Probably outline1 and ouline2.
by Nuoya Jiang
Sat Jan 11, 2020 2:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: using Kp vs Kc
Replies: 13
Views: 34

Re: using Kp vs Kc

In fact, you can use both. Table 5G.2 shows an example of how Kc works for gas reactions.
by Nuoya Jiang
Sat Jan 11, 2020 2:39 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic and endothermic reactions
Replies: 4
Views: 23

Re: Exothermic and endothermic reactions

We can see the exothermic reaction as a reaction with "heat" as a product. Thus if we increase temperature of the system, we are indeed increasing the "concentration" of heat (product), so the reaction goes to the left. It works the same as in an endothermic reaction. We simply s...
by Nuoya Jiang
Thu Dec 05, 2019 1:00 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 disperson
Replies: 6
Views: 23

Re: London disperson

Yes, because the electrons in all the molecules have a chance to move to a place where a dipole appears.
by Nuoya Jiang
Thu Dec 05, 2019 12:58 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxolate Chelate
Replies: 6
Views: 52

Re: Oxolate Chelate

No, chelates can form at least BIdentate.
by Nuoya Jiang
Thu Dec 05, 2019 12:57 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: ICE tables
Replies: 3
Views: 28

Re: ICE tables

We need to know the basic calculation of the concentration of titration for a strong acid and a strong base, plus the situation of the equivalence point involving a weak base and a strong acid, or a strong base and a weak acid.
by Nuoya Jiang
Thu Dec 05, 2019 12:51 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelate
Replies: 5
Views: 42

Re: Chelate

A few examples of biological importance we covered in class are necessary to know, at least.
by Nuoya Jiang
Thu Dec 05, 2019 12:43 pm
Forum: Amphoteric Compounds
Topic: Amphoteric vs Amphiprotic
Replies: 9
Views: 54

Re: Amphoteric vs Amphiprotic

polyprotic means an acid can give more than one proton and its conjugate base can accept more than one proton.
by Nuoya Jiang
Wed Nov 27, 2019 7:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test #2 handback
Replies: 11
Views: 75

Re: Test #2 handback

Are we going to get them on week 10?
by Nuoya Jiang
Wed Nov 27, 2019 6:47 pm
Forum: Student Social/Study Group
Topic: Grades
Replies: 18
Views: 203

Re: Grades

Will we be curved based on the performance of the whole class?
by Nuoya Jiang
Wed Nov 27, 2019 6:41 pm
Forum: Hybridization
Topic: Sigma and Pi Bonds
Replies: 21
Views: 70

Re: Sigma and Pi Bonds

Single bond: sigma bond
Double bond: one sigma bond+one pi bond
Triple bond: one sigma bond+two pi bonds
by Nuoya Jiang
Wed Nov 27, 2019 6:39 pm
Forum: Conjugate Acids & Bases
Topic: strength of an acid and its conjugate base
Replies: 3
Views: 21

strength of an acid and its conjugate base

Is it true that a relatively weak acid has a stronger conjugate base and a relatively weak base has a stronger acid?
by Nuoya Jiang
Wed Nov 27, 2019 6:35 pm
Forum: Naming
Topic: 9C.3
Replies: 6
Views: 48

Re: 9C.3

The order you put your ligand doesn't. The order seems only easier to name, instead.
by Nuoya Jiang
Sun Nov 24, 2019 3:34 pm
Forum: Naming
Topic: Final Format
Replies: 6
Views: 27

Re: Final Format

More questions cover topics from the beginning of this quarter, with a focus after the midterm, on the molecular shape, bonding, acids and base.
by Nuoya Jiang
Sun Nov 24, 2019 3:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Shape
Replies: 29
Views: 187

Re: Bent Shape

one or two, which also decide the bond angle.
by Nuoya Jiang
Sun Nov 24, 2019 3:30 pm
Forum: Dipole Moments
Topic: Melting points
Replies: 15
Views: 103

Re: Melting points

The bond strength of a double bond is talking about "INTRA" molecular force, while the melting point is related to "INTER" molecular force.
by Nuoya Jiang
Sun Nov 24, 2019 3:27 pm
Forum: Biological Examples
Topic: Heme complex
Replies: 8
Views: 53

Re: Heme complex

I think on a test, we would be asked to identify which transition metal is bound to which ligand at least, and describe why this is important for all living things?
by Nuoya Jiang
Sun Nov 24, 2019 3:22 pm
Forum: Student Social/Study Group
Topic: Any tips on how to catch up in this class?
Replies: 16
Views: 88

Re: Any tips on how to catch up in this class?

Professor Lavelle has posted some outlines/learning outcomes on his class website. Read through them and find some videos online to catch up. Those videos online are good learning materials because they are more focused and test problem oriented. Good luck.
by Nuoya Jiang
Wed Nov 13, 2019 7:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear VSEPR model
Replies: 21
Views: 128

Re: Linear VSEPR model

That would be a bent shape. I believe we'll talk about this in a few days.
by Nuoya Jiang
Wed Nov 13, 2019 7:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR model angles
Replies: 7
Views: 39

Re: VSEPR model angles

Yes, they are always popular test materials.
by Nuoya Jiang
Wed Nov 13, 2019 7:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Class grading
Replies: 12
Views: 199

Re: Class grading

For this midterm, I don't think he would curve, either.
by Nuoya Jiang
Wed Nov 13, 2019 7:50 pm
Forum: Dipole Moments
Topic: Hydrogen bonds
Replies: 17
Views: 88

Re: Hydrogen bonds

Only with O, F and N because they have the highest electronegativity.
by Nuoya Jiang
Wed Nov 13, 2019 7:49 pm
Forum: Properties of Light
Topic: Midterm Solution Q2.A
Replies: 2
Views: 46

Re: Midterm Solution Q2.A

Question2 tests your knowledge of the photoelectric effect, which indicates that light can be viewed as particles. The first thing you need to do is to convert 492 KJ for a mole of light particles to the work function of a single light particle.
by Nuoya Jiang
Fri Nov 08, 2019 10:35 am
Forum: Octet Exceptions
Topic: elements in 3p block
Replies: 8
Views: 97

Re: elements in 3p block

Their n=3, which indicates that they are able to have 3d orbitals.
by Nuoya Jiang
Fri Nov 08, 2019 10:34 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Formal Charge
Replies: 9
Views: 486

Re: Formal Charge

After checking the formal charge, we also prefer structures that have -1 on the more electronegative atoms.
by Nuoya Jiang
Fri Nov 08, 2019 10:33 am
Forum: Dipole Moments
Topic: Drawing Unpaired Electrons
Replies: 7
Views: 48

Re: Drawing Unpaired Electrons

Yes, always include all the electrons in the structure.
by Nuoya Jiang
Fri Nov 08, 2019 10:31 am
Forum: Lewis Structures
Topic: Midterm grades
Replies: 26
Views: 249

Re: Midterm grades

Like Test1 which is also graded by the TAs, it should take one week.
by Nuoya Jiang
Fri Nov 08, 2019 10:30 am
Forum: Dipole Moments
Topic: How do i know if a molecule has a dipole moment?
Replies: 7
Views: 60

Re: How do i know if a molecule has a dipole moment?

A symmetric molecule usually does not have a dipole moment, but if it is asymmetric, check the difference in electronegativity, so you can find out its dipole moment.
by Nuoya Jiang
Fri Nov 08, 2019 10:28 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarisability vs Polarizing Power
Replies: 15
Views: 112

Re: Polarisability vs Polarizing Power

Polarizing power describes the power of a cation to distort an anion, and polarisability is the property of how easy an anion is distorted.
by Nuoya Jiang
Fri Nov 08, 2019 10:25 am
Forum: General Science Questions
Topic: Test 2
Replies: 20
Views: 142

Re: Test 2

It should cover materials started from "bond strength" and "molecular shape", just after the midterm.
by Nuoya Jiang
Fri Nov 08, 2019 10:24 am
Forum: Octet Exceptions
Topic: Lewis Acids and Bases?
Replies: 11
Views: 76

Re: Lewis Acids and Bases?

Lewis Acids are electron acceptors and Lewis Bases are electron donors.
by Nuoya Jiang
Sun Oct 27, 2019 1:09 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 9
Views: 27

Re: Ionization Energy

A positive sign means taking energy into the system or the system needs energy to so some certain activity. The negative sign means the system releases energy or loses energy during activity.
by Nuoya Jiang
Sun Oct 27, 2019 1:06 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm Topics Covered
Replies: 7
Views: 65

Re: Midterm Topics Covered

I think it would cover the Quantum World all the way to the start of molecular shape, for we still have one week before the midterm.
by Nuoya Jiang
Sun Oct 27, 2019 1:02 pm
Forum: Lewis Structures
Topic: Drawing the structure
Replies: 7
Views: 48

Re: Drawing the structure

Yes, it is a Lewis structure and P is able to extend the octet because it is in the d-block.
by Nuoya Jiang
Sun Oct 27, 2019 1:00 pm
Forum: Trends in The Periodic Table
Topic: Exceptions in the trends
Replies: 4
Views: 42

Exceptions in the trends

Hi, what are some examples of exceptions in the periodic trends, such as the radii of oxygen and nitrogen do not fit the trend?
by Nuoya Jiang
Sun Oct 27, 2019 12:57 pm
Forum: Lewis Structures
Topic: Expanded Octet
Replies: 6
Views: 30

Re: Expanded Octet

Elements that have d-orbitals are able to fit more than 8 valence electrons, so they can expand the Octet.
by Nuoya Jiang
Sun Oct 20, 2019 8:16 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: s-, p-, d- ,f- orbitals
Replies: 10
Views: 83

Re: s-, p-, d- ,f- orbitals

n=2, (principle quantum number, shell); l=1, (subshell is p); x describes the axis of the orbital.
by Nuoya Jiang
Sun Oct 20, 2019 8:14 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals
Replies: 8
Views: 67

Re: Orbitals

So for Cr, 5 electrons in 5 3d orbitals and 1 electron in 4s has lower energy than 4 electrons in 3d, and 2 electron in 4s.
by Nuoya Jiang
Sun Oct 20, 2019 8:05 pm
Forum: *Shrodinger Equation
Topic: Schrodinger for exam
Replies: 9
Views: 124

Re: Schrodinger for exam

I think we only need to understand the relationship between Schrodinger's equation and quantum numbers. After all, the emphasis of Focus 1 (Quantum World) is still on the model of electrons and properties of light.
by Nuoya Jiang
Sun Oct 20, 2019 8:01 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Advice for studying
Replies: 58
Views: 555

Re: Advice for studying

Do every homework question and read concepts on the text bool as well. Tne syllabus says 1/8 of the homework questions are likely to be on the exams as well, so we should definitely pay attention to those questions.
by Nuoya Jiang
Sun Oct 20, 2019 7:58 pm
Forum: Properties of Light
Topic: MidTerms and Finals
Replies: 11
Views: 85

Re: MidTerms and Finals

I think the midterm is in the evening, lasting for 2 hours, so it is unlikely on a discussion session. For the final, it won't be in the lecture or the discussion.
by Nuoya Jiang
Sun Oct 13, 2019 1:14 pm
Forum: Photoelectric Effect
Topic: Frequency vs Energy per Photon
Replies: 4
Views: 44

Re: Frequency vs Energy per Photon

Increasing the number of photons means increasing the intensity of light, counterintuitively. Only when the energy of each photon is sufficient, can it remove a electron. One photon is responsible for removing an electron, so it is the energy (frequency) counts, not the number of photons.
by Nuoya Jiang
Sun Oct 13, 2019 1:03 pm
Forum: Photoelectric Effect
Topic: 1B.9
Replies: 2
Views: 52

Re: 1B.9

For this question, first calculate the total energy the lamp produced in 2 seconds. Then use E=hc/\lambda[/tex] to calculate the energy of a single violet photon. Divide the first result (total energy) with your result in the second step (energy of a single photon), should give to the answer to the ...
by Nuoya Jiang
Sun Oct 13, 2019 12:53 pm
Forum: Properties of Light
Topic: 1A.11
Replies: 3
Views: 33

Re: 1A.11

For this question, try to think of the the lower energy level of these groups of lines. For example, for the Lyman series, these lines show the lower energy level of the transition of an electron from different energy levels is n=1, while for Balmer, it is n=2.
by Nuoya Jiang
Sun Oct 13, 2019 12:49 pm
Forum: DeBroglie Equation
Topic: DeBroglie Equation
Replies: 9
Views: 91

Re: DeBroglie Equation

Considering the DeBroglie equation, which needs you to calculate the momentum=mv, the light does not have a mass, so you can't use this equation for light.
by Nuoya Jiang
Wed Oct 09, 2019 8:06 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Typical wavelength for spectrum
Replies: 2
Views: 43

Typical wavelength for spectrum

Hi, why is the UV light a typical experiment tool to conduct atomic spectroscopy? I know it has great energy and can probably excite electrons, but why do we usually use this wavelength of light to conduct related experiments? Thank you.
by Nuoya Jiang
Sat Oct 05, 2019 3:32 pm
Forum: Balancing Chemical Reactions
Topic: Fractions in Balancing Equations
Replies: 11
Views: 131

Re: Fractions in Balancing Equations

After you finish balancing the chemical equations, always remember to convert fractions into integrals because fractions should never appear in chemical equations to the definition of stoichiometric coefficients.
by Nuoya Jiang
Sat Oct 05, 2019 3:28 pm
Forum: Molarity, Solutions, Dilutions
Topic: Converting Before or After?
Replies: 10
Views: 63

Re: Converting Before or After?

It would be easier and clearer to do all the converting after you solve the question and do the correct the calculations, and if you can cancel the units and cut it to a reasonable/desired unit, the answer would probably be right.
by Nuoya Jiang
Sat Oct 05, 2019 3:24 pm
Forum: Properties of Light
Topic: Classical Mechanics vs. Quantum Mechanics
Replies: 4
Views: 31

Re: Classical Mechanics vs. Quantum Mechanics

Hi, so in a classical mechanics, we see things and explain the reasons behind them in a macro scale, and as a result, our measurement is continuous. In a quantum mechanics, or a situation for micro things, everything is so small that we can only use discrete numbers to describe a transition. Try to ...
by Nuoya Jiang
Sat Oct 05, 2019 3:17 pm
Forum: Significant Figures
Topic: Question about significant figures and rounding a number
Replies: 4
Views: 66

Re: Question about significant figures and rounding a number

Thank you for the replying. I saw the textbook said that when we rounded numbers with stuff like 0.75, we should round it to the nearest even number, so 0.8(+0.5), but for 0.65, it should be rounded to 0.6(-0.5). Is this right?
by Nuoya Jiang
Tue Oct 01, 2019 3:50 pm
Forum: Significant Figures
Topic: Question about significant figures and rounding a number
Replies: 4
Views: 66

Question about significant figures and rounding a number

Hi, I have a question about rounding numbers to its nearest integral, tenth, or hundredth, etc, and how the significant figure can effect that. For example, how to round 5.454545 and 5.55555 and make them each have 1,2,3 or 4 significant figures? Thank you.
by Nuoya Jiang
Mon Sep 30, 2019 9:46 pm
Forum: Limiting Reactant Calculations
Topic: Methods of identifying Limiting Reactants
Replies: 5
Views: 89

Re: Methods of identifying Limiting Reactants

Hi Baoying, calculating the limiting reactant can be a tough task because the evidence we use to prove which reactant is limited is indeed the balanced chemical equations with their stoichiometric coefficients. Therefore, you either calculate the moles of each reactant to find the limiting one as th...

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