Search found 72 matches

by Jessica Li 4F
Sun Jan 26, 2020 4:09 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Change
Replies: 4
Views: 20

Re: Phase Change

Those values should be given to you (I.e. the heat of vaporization of water is 40.7 kJ/mol), but it is up to you to multiply those values accordingly depending on how much of something you have (I.e. moles of water).
by Jessica Li 4F
Sun Jan 26, 2020 4:05 pm
Forum: Phase Changes & Related Calculations
Topic: Combustion
Replies: 5
Views: 24

Re: Combustion

Agreed. Combustion is a unique type of reaction in which an organic/carbon-based molecule reacts with oxygen to produce CO2 and water.
by Jessica Li 4F
Sun Jan 26, 2020 4:04 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy & Spontaneity
Replies: 4
Views: 11

Re: Enthalpy & Spontaneity

If a reaction is spontaneous, it means that no additional energy is needed for the reaction to occur. It will just happen naturally (although this doesn’t indicate how fast a reaction will occur). You can determine spontaneity using Gibbs free energy or delta G — if the value is negative in a reacti...
by Jessica Li 4F
Sun Jan 26, 2020 3:58 pm
Forum: Phase Changes & Related Calculations
Topic: phase changes
Replies: 6
Views: 17

Re: phase changes

A phase change occurs any time you convert a substance, between the three states of matter/phases: solid, liquid, and gas. There is also a fourth stage but it should be irrelevant to the class. You can determine which changes are exothermic and endothermic by comparing the relative energies of the d...
by Jessica Li 4F
Wed Jan 22, 2020 10:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1 Practice Worksheet #5
Replies: 6
Views: 85

Re: Test 1 Practice Worksheet #5

I actually got 8.6 - I think you forgot to convert the given pKa value to pKb, as the molecule you are dealing with is actually the base.
by Jessica Li 4F
Sat Jan 18, 2020 7:36 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5I.11 units
Replies: 5
Views: 28

Re: 5I.11 units

Yes, you could just calculate the mmol to moles (1 mol = 1000 mmol) and then divide that by the volume (0.500 L) to get the concentration.
by Jessica Li 4F
Sat Jan 18, 2020 4:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc sig figs
Replies: 4
Views: 16

Kc sig figs

When determining how many sig figs to include in our end values, do we factor in the sig figs of given K values too? For instance, if you want to find the concentration of H2 and have the concentrations of I2 and HI up to 3 sig figs, but your given K value only has 2, would you round the value of [H...
by Jessica Li 4F
Sat Jan 18, 2020 3:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G.1
Replies: 2
Views: 12

5G.1

For 5G.1 part c, would the explanation that it is false because the concentrations of the products and reactants don't affect the value of K itself be correct?
by Jessica Li 4F
Sat Jan 18, 2020 3:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5E.2 table??
Replies: 3
Views: 14

Re: 5E.2 table??

I think it is a typo and it should actually refer to Table 5G.2, which other problems refer to. However, I think there is also an error between the given Kc value in the table and the one in the solutions manual, so I'd just be careful of that.
by Jessica Li 4F
Wed Jan 15, 2020 7:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.39
Replies: 2
Views: 20

5.39

Could someone explain how to do 5.39? I'm having trouble with the given Kc -- it should be 6.1 * 10^23 according to the table in the textbook but the solutions manual seems to say it's 6.1 * 10^-3, so I'm a bit confused.

Thanks!
by Jessica Li 4F
Sun Jan 12, 2020 10:13 am
Forum: Ideal Gases
Topic: Test 1
Replies: 7
Views: 49

Test 1

How much of ideal gases will we have to know for Test 1? Thank you!
by Jessica Li 4F
Sun Jan 12, 2020 10:04 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Cancelling out the X
Replies: 3
Views: 31

Re: Cancelling out the X

You are allowed to cancel out the x, or deem it negligible to get an approximation of a K value or concentration of a reactant/product, if the K value is very small. Usually the cutoff is 10^-4, so if it is less than that, you can solve the equation without including the x. This usually happens when...
by Jessica Li 4F
Sun Jan 12, 2020 10:00 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc vs. Kp [ENDORSED]
Replies: 4
Views: 26

Re: Kc vs. Kp [ENDORSED]

Kc applies to molar concentration (M) of gases or aqueous solutions, while Kp applies only to gases and is respective to their partial pressures.
by Jessica Li 4F
Sun Jan 12, 2020 9:58 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Q
Replies: 3
Views: 12

Re: K and Q

The concentrations of solids and liquids don't change much compared to those of aqueous solutions and gases, so they are negligible/cancel out as 1 basically.
by Jessica Li 4F
Fri Jan 10, 2020 10:30 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Why does only Temp affect K?
Replies: 8
Views: 38

Re: Why does only Temp affect K?

For any given concentrations, the ratio will always be the same, regardless of what the concentrations are, so they don't change the value of K. However, temperature affects K because changes in temperature shift the reaction toward a certain side. Think of temp. as a reactant or product in the reac...
by Jessica Li 4F
Sat Dec 07, 2019 5:09 pm
Forum: Biological Examples
Topic: Marshmallow Review #22
Replies: 1
Views: 38

Re: Marshmallow Review #22

Myoglobin can bind one O2. Since four myoglobins make up a hemoglobin molecule, hemoglobin can bind 4 O2 molecules.
by Jessica Li 4F
Mon Dec 02, 2019 4:42 pm
Forum: Identifying Acidic & Basic Salts
Topic: Names of Acids and Bases
Replies: 3
Views: 53

Names of Acids and Bases

Do we have to know the names of acids and bases and their corresponding formulas? For instance, bromous acid?
by Jessica Li 4F
Mon Dec 02, 2019 12:04 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Final Study Methods
Replies: 11
Views: 53

Re: Final Study Methods

To echo the above statements, I know there are a lot of problems in the textbook that he assigns, but I'd just do all of them, or least all the different kinds of problems, as he does usually pull one question from the textbook and puts it in the test. I also think the UA workshops are very helpful,...
by Jessica Li 4F
Mon Dec 02, 2019 12:02 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Difference between inorganic and organic
Replies: 4
Views: 37

Re: Difference between inorganic and organic

Organic molecules usually have carbon atoms involved in their makeup, while inorganic molecules don't.
by Jessica Li 4F
Mon Dec 02, 2019 12:02 pm
Forum: Conjugate Acids & Bases
Topic: Ligands
Replies: 12
Views: 57

Re: Ligands

Ligands donate a whole electron pair to the central atom in a coordination compound. For instance, a lone pair in O2 contributes to the whole of a bond between O2 and Fe when it bends to Fe in a molecule like myoglobin.
by Jessica Li 4F
Mon Dec 02, 2019 12:00 pm
Forum: Polyprotic Acids & Bases
Topic: Spectator ions
Replies: 3
Views: 395

Re: Spectator ions

Usually I'd look for the ions that stay in the same state of matter/that repeat on the reactant and products side of the reaction. For instance, if you have Na+(aq) on one side and Na+(aq) on the other, it is a spectator ion. However, if you have Na+(aq) and NaF(s) on the other, it would not be a sp...
by Jessica Li 4F
Mon Dec 02, 2019 11:58 am
Forum: Lewis Acids & Bases
Topic: Difference
Replies: 4
Views: 26

Re: Difference

We will probably have to know types of acids generally and their corresponding strengths.
by Jessica Li 4F
Mon Dec 02, 2019 11:57 am
Forum: Amphoteric Compounds
Topic: Identifying Amphoteric Compounds
Replies: 5
Views: 28

Re: Identifying Amphoteric Compounds

Yeah, Lavelle hasn't really gone over amphoteric compounds in lecture yet, so I think it would be best to just know that H2O is the standard amphoteric compound because it has the same concentration of H+ and OH- ions.
by Jessica Li 4F
Mon Dec 02, 2019 11:56 am
Forum: Bronsted Acids & Bases
Topic: Acid strength
Replies: 2
Views: 19

Re: Acid strength

Since the F atom in HF pulls the H so strongly, it's hard for the H to "escape" and break the bond between them two to result in their respective ions. In addition, the trend goes that HF < HCl < HBr < HI in terms of acid strength because the bond strengths (and lengths) are increasingly w...
by Jessica Li 4F
Mon Dec 02, 2019 11:53 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Changes with temp?
Replies: 2
Views: 29

Re: Changes with temp?

It is easier for molecules to dissociate as you increase the temperature, as this increases energy. So you can think of it with any molecule - if you increase energy, it is easier to break bonds.
by Jessica Li 4F
Mon Dec 02, 2019 11:51 am
Forum: Conjugate Acids & Bases
Topic: Naming
Replies: 4
Views: 50

Re: Naming

To add onto the coordination compounds, if the compound as a whole is negatively charged, you want to add an -ate to the ending of the central atom instead.
by Jessica Li 4F
Mon Dec 02, 2019 11:51 am
Forum: Conjugate Acids & Bases
Topic: Naming
Replies: 4
Views: 50

Re: Naming

To add onto the coordination compounds, if the compound as a whole is negatively charged, you want to add an -ate to the ending of the central atom instead.
by Jessica Li 4F
Mon Dec 02, 2019 11:50 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Weak acids & pH
Replies: 4
Views: 49

Re: Weak acids & pH

Solvents can vary in their pH, and therefore the concentration of overall H+ and OH- ions there are in a given solution. The presence of the H+ and OH- already in the solvent would affect how much of the solute can dissociate.
by Jessica Li 4F
Fri Nov 22, 2019 1:45 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating Ligands
Replies: 2
Views: 32

Chelating Ligands

How do chelating ligands work exactly? What are more examples of chelating ligands and their uses?
by Jessica Li 4F
Fri Nov 22, 2019 1:39 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cisplatin binding
Replies: 1
Views: 21

Cisplatin binding

Can someone explain how cisplatin binds to DNA again? I understand that it binds to an exposed N atom on guanine, but do the Cl atoms then get displaced for Pt to bind to nitrogen? Also, would the bonds be intramolecular or intermolecular? Thanks!
by Jessica Li 4F
Tue Nov 19, 2019 6:41 pm
Forum: Hybridization
Topic: 2.57
Replies: 2
Views: 20

2.57

Does anyone have the answer for 2.57? It doesn't seem to be included in the solutions manual, and I just want to check to see if my answer is correct or not.

Thanks!
by Jessica Li 4F
Tue Nov 19, 2019 5:22 pm
Forum: Hybridization
Topic: Hybridization of H2
Replies: 2
Views: 21

Hybridization of H2

Does H2, since its linear, have a sp hybridization even though it doesn't have "access," per say, to p orbitals in its ground state electrons? Would it not have hybridized orbitals in general?
by Jessica Li 4F
Tue Nov 19, 2019 10:35 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape and Structure
Replies: 1
Views: 23

Molecular Shape and Structure

Could someone explain the answer to the following problem?

For the following nitrogen oxide compounds:
a. Draw the most stable lewis structure.
b. Determine the shape.
c. Determine whether the compound is polar or nonpolar.

Nitric Oxide (NO)

Nitrogen Dioxide (NO2)

N2O

Thanks!
by Jessica Li 4F
Sat Nov 16, 2019 12:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: How to study for VSEPR?
Replies: 9
Views: 84

Re: How to study for VSEPR?

I agree with all of the comments above. 2E has a lot of great practice, but if you want to do more, there should be a lot of other worksheets on Google. I think a good method to memorize the shapes and angles is to start with the VSEPR formula and overall shapes without taking into account lone pair...
by Jessica Li 4F
Sat Nov 16, 2019 12:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Distortion and Polarizability
Replies: 2
Views: 24

Re: Distortion and Polarizability

Polarizability doesn't relate to an electron, but rather the whole atom. The polarizability of an atom is essentially how easily its electron cloud can be distorted.
by Jessica Li 4F
Sat Nov 16, 2019 12:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 28

Bond Angles

For tetrahedral molecules (or of any shape really) like CHCl3 or POCl3 that are polar but don't have any lone pairs, why are the bond angles all 109.5 degrees (according to the solutions manual)? Would not the more polar atoms attached to the central atom push the other atoms away slightly more?
by Jessica Li 4F
Sat Nov 16, 2019 12:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape of ClO2+
Replies: 6
Views: 44

Re: Shape of ClO2+

I think the more accurate shape of ClO2+ is bent, but if you were to describe it generally (without taking into account the lone pair on Cl), it would have a trigonal planar shape because there are 3 regions of electron density.
by Jessica Li 4F
Tue Nov 12, 2019 9:09 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: 3F19.c.
Replies: 2
Views: 25

3F19.c.

Why does the different structure of the 2 molecules, pentane and 2,2-dimethylpropane, make their boiling points different?
by Jessica Li 4F
Thu Nov 07, 2019 11:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance Delocalization
Replies: 5
Views: 40

Re: Resonance Delocalization

In resonance structures, electrons are not just limited to the single/double bonds as seen in the different Lewis structures, but actually delocalized, or spread out, among all of these bonds. Therefore, no resonance structure is the actual Lewis structure of the molecule. Rather, the molecule is a ...
by Jessica Li 4F
Thu Nov 07, 2019 11:00 pm
Forum: Octet Exceptions
Topic: radicals
Replies: 3
Views: 27

Re: radicals

To second that, the more electronegative atom usually wants more electrons. If it is that the radical electron would give that element more electrons, that it would get the electron on the Lewis structure and vice versa. However, formal charge is also important, so I'd keep that in mind.
by Jessica Li 4F
Wed Nov 06, 2019 10:40 am
Forum: Administrative Questions and Class Announcements
Topic: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE
Replies: 53
Views: 2439

Re: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE

For #10 on worksheet 3, why is wavelength not related to speed per De Broglie's equation?

Here is the question: 10. Which of the following statements regarding electromagnetic radiation is true?
by Jessica Li 4F
Tue Nov 05, 2019 10:44 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Constant
Replies: 1
Views: 28

Rydberg Constant

For the Rydberg equation, does the negative sign cancel out?
by Jessica Li 4F
Tue Nov 05, 2019 10:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Dino nuggets 11b
Replies: 3
Views: 63

Re: Dino nuggets 11b

Emission means releasing energy, which means that delta E itself will be negative, as energy is lost.
The energy of a photon, however, can never be negative, so it is always the positive absolute value of delta E.
by Jessica Li 4F
Wed Oct 30, 2019 6:37 pm
Forum: Formal Charge and Oxidation Numbers
Topic: When would a compound not have FC=0?
Replies: 2
Views: 26

Re: When would a compound not have FC=0?

It would be when the compound itself is charged/a polyatomic ion.To add on to the previous answer, since SO32- has a 2- charge overall already, the formal charges (if correctly calculated) should also come out to -2.
by Jessica Li 4F
Wed Oct 30, 2019 6:34 pm
Forum: Octet Exceptions
Topic: expanded valence shells
Replies: 2
Views: 20

Re: expanded valence shells

I think stability depends a lot on the formal charges of the atoms involved. Since atoms with expanded valence shells tend to have lesser formal charges (hence why they are expanded rather than not), I would say that they are definitely stable.
by Jessica Li 4F
Wed Oct 30, 2019 6:33 pm
Forum: Lewis Structures
Topic: Valence Electrons from Periodic Table
Replies: 10
Views: 77

Re: Valence Electrons from Periodic Table

I think it's helpful if you have time to write down the electron configuration. Then, you can just count all the subscripts in the highest n level and add them up. This helps prevent confusion with the d orbitals. For instance, for Zinc, the config would be 1s2 2s2 2p6 3s2 3p6 3d10 4s2. Since n =4 i...
by Jessica Li 4F
Wed Oct 30, 2019 6:30 pm
Forum: Ionic & Covalent Bonds
Topic: Partial charge
Replies: 4
Views: 28

Re: Partial charge

I believe that covalent bonds have partial charges because they only have semi-ionic characteristics, while ionic bonds have actual full charges (i.e. Na+ and Cl- (the plus and minus charges)) and their own semi-covalent characteristics.
Correct me if I'm wrong though!
by Jessica Li 4F
Wed Oct 30, 2019 11:45 am
Forum: Lewis Structures
Topic: Valence electrons
Replies: 5
Views: 47

Re: Valence electrons

However, since phosphorus has a technically empty 3d orbital, it can bond to other elements in a way so that it can have up to 10 valence electrons, as with PCl5.
Hope that clarifies things!
by Jessica Li 4F
Fri Oct 25, 2019 4:14 pm
Forum: Lewis Structures
Topic: Single or Double Bonds
Replies: 4
Views: 29

Re: Single or Double Bonds

For elements who cannot have expanded octets, you want to draw bonds in a way so all elements (except H and He) have octets. For instance, CO2 would need double bonds, while CF4 only needs single bonds. For elements who can have expanded octets, you want to calculate the formal charges of all the at...
by Jessica Li 4F
Fri Oct 25, 2019 4:12 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm 2
Replies: 4
Views: 44

Re: Midterm 2

I think there's only one midterm (on Nov. 6), and that one will be cumulative all the way from Test 1.
by Jessica Li 4F
Fri Oct 25, 2019 4:12 pm
Forum: Octet Exceptions
Topic: Expanded Valence Shells
Replies: 4
Views: 22

Re: Expanded Valence Shells

P, S, and Cl are definitely not the only elements that can have expanded octets. They are just when the expanded octet for elements begins - elements with associated d orbitals should all be able to have expanded octets.
by Jessica Li 4F
Wed Oct 23, 2019 11:38 am
Forum: Lewis Structures
Topic: Lewis Structure angles
Replies: 3
Views: 30

Lewis Structure angles

When drawing Lewis structures, does the angle at which we draw them have to be accurate? For example, with NO3-, making the oxygens perpendicular to N versus at a slanted angle?
by Jessica Li 4F
Mon Oct 21, 2019 5:46 pm
Forum: Photoelectric Effect
Topic: Module Assessment Question
Replies: 2
Views: 34

Module Assessment Question

The question is "Photoelectric experiments gave rise to a new equation relating the energy of light to its frequency. Select the right equation."

Is the answer E = hv instead of the one with work function and kinetic energy, and why?
by Jessica Li 4F
Fri Oct 18, 2019 3:39 pm
Forum: DeBroglie Equation
Topic: Rydberg and De Brogile
Replies: 3
Views: 40

Re: Rydberg and De Brogile

I think it depends on what values you are given and what the question is asking for. The Rydberg equation is usually used when you're trying to find which energy levels an electron is jumping to/from, or when you're trying to find the wavelength of emission when given the energy levels the electron ...
by Jessica Li 4F
Fri Oct 18, 2019 3:35 pm
Forum: *Particle in a Box
Topic: 1B. Quantum Theory and model of an atom
Replies: 2
Views: 69

Re: 1B. Quantum Theory and model of an atom

You could also draw in possible paths the electron could take/be to show that you are uncertain of where exactly the electron is.
by Jessica Li 4F
Fri Oct 18, 2019 3:34 pm
Forum: Properties of Electrons
Topic: Equations for Test
Replies: 9
Views: 74

Equations for Test

What equations relevant to the quantum unit will be given on a test? Will we have to memorize the Schroedinger Equation, etc.?
by Jessica Li 4F
Fri Oct 18, 2019 3:31 pm
Forum: *Shrodinger Equation
Topic: Quantum Number
Replies: 2
Views: 44

Re: Quantum Number

If an atom has an electron configuration such that some electrons are paired in an orbital, and you are trying to find an electron in a paired orbital, the fourth quantum number would help distinguish between the one with an up spin and the one with a down spin. Therefore, yes, the fourth quantum nu...
by Jessica Li 4F
Fri Oct 18, 2019 3:24 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: d orbitals
Replies: 1
Views: 26

d orbitals

I know that the p orbitals can be written as px, py, and pz, but what about the d orbitals?
Also, for tests, will we have to be specific and write out the subscripts, or can we just write, for example in carbon, 1s22s22p2 instead of 1s2 2s2 2px?
by Jessica Li 4F
Fri Oct 18, 2019 3:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4s and 3d electron configurations
Replies: 1
Views: 31

4s and 3d electron configurations

In lecture today, Professor Lavelle talked about how when writing electron configurations, we should do, for example with Scandium, [insert noble gas]3d^1 4s^2 and NOT [noble gas]4s^2 3d^1. However, in my high school chemistry class, we always flipped 4s and 3d - I'm wondering why this is? I also un...
by Jessica Li 4F
Mon Oct 14, 2019 4:41 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Equation
Replies: 4
Views: 30

Re: Uncertainty Equation

Just using the equation, (uncertainty in momentum)(uncertainty in position) >= h/4pi, you can tell that if one of the factors increases and you want the product to stay the same, the other factor must decrease.
Hope this helps!
by Jessica Li 4F
Mon Oct 14, 2019 4:39 pm
Forum: DeBroglie Equation
Topic: HW Question 1B.23
Replies: 2
Views: 34

Re: HW Question 1B.23

To add on, all such values should be given on the reference sheet, especially for tests, including the mass of an electron as well.
by Jessica Li 4F
Mon Oct 14, 2019 4:36 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post-Module Question
Replies: 3
Views: 38

Re: Atomic Spectra Post-Module Question

I agree with the above answers. Although you get a negative value for frequency when you calculate using the equation, it is because frequency is emitted and therefore "lost." When anything is "lost," it will be expressed as a negative value in an equation. However, the actual fr...
by Jessica Li 4F
Mon Oct 14, 2019 4:31 pm
Forum: Properties of Light
Topic: 1A.15
Replies: 4
Views: 93

Re: 1A.15

Yeah, you have to assume that the final energy level is n = 1. Then you can find the energy emitted using the c = wavelength(frequency) equation and the E = hv equation to input into the Rydberg equation.
by Jessica Li 4F
Fri Oct 04, 2019 11:41 pm
Forum: Balancing Chemical Reactions
Topic: Reaction Stoichiometry L.35
Replies: 2
Views: 43

Re: Reaction Stoichiometry L.35

First, you should balance the equations to the following (states of matter not included): Fe + Br2 -> FeBr2 3FeBr2 + Br2 -> Fe3Br8 Fe3Br8 + 4Na2CO3 -> 8NaBr + 4CO2 + Fe3O4 Then use dimensional analysis and mole ratios to solve, from the amount of NaBr given to iron: 2.50 t NaBr * (1000 kg NaBr/1 t N...
by Jessica Li 4F
Fri Oct 04, 2019 11:27 pm
Forum: Balancing Chemical Reactions
Topic: Chemical Equations H11
Replies: 1
Views: 40

Re: Chemical Equations H11

It would be:
Fe2O3(s)+3CO(g)-->2Fe(s)+3CO2(g)
by Jessica Li 4F
Fri Oct 04, 2019 11:26 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question
Replies: 3
Views: 55

Re: Question

You are supposed to multiply by 1000 to convert the liters in the Molarity measurement (which is moles/liters) into mL, and there are 1000 mL in one liter.
by Jessica Li 4F
Fri Oct 04, 2019 8:13 pm
Forum: Balancing Chemical Reactions
Topic: M9
Replies: 2
Views: 45

Re: M9

It's basically the same as any other equation, except for the compounds that are ionic and soluble in water add the (aq) subscript on the bottom. For the solids, indicate that they are solid and write them as whole compounds. However, there are also complete ionic equations in which you have to sepa...
by Jessica Li 4F
Fri Oct 04, 2019 8:10 pm
Forum: Limiting Reactant Calculations
Topic: Percent or theoretical yield
Replies: 14
Views: 146

Re: Percent or theoretical yield

I think we might, but the simple answer is just that in real life, things never go exactly right. There is a lot of potential for experimental error, as well as secondary reactions that make the actual yield lesser than the theoretical yield.
by Jessica Li 4F
Fri Oct 04, 2019 8:08 pm
Forum: Empirical & Molecular Formulas
Topic: L. 39
Replies: 2
Views: 48

Re: L. 39

To elaborate on the previous answer, for part a you want to make sure to subtract the crucible weight from the total weight to find the weight of the product itself, and then take the given mass of tin to find the percentages of both tin and oxygen, as they are the only two elements involved in the ...
by Jessica Li 4F
Fri Oct 04, 2019 8:03 pm
Forum: SI Units, Unit Conversions
Topic: SI Units
Replies: 3
Views: 56

Re: SI Units

The SI units themselves don't ascend and descend in orders of 3. I think the orders of 3 just make it a bit more convenient when converting SI units between each other, and so you don't have to memorize and name all the different powers of 10. The only major exception, as Professor Lavelle said, is ...
by Jessica Li 4F
Fri Oct 04, 2019 7:58 pm
Forum: Administrative Questions and Class Announcements
Topic: First Test in Discussion
Replies: 13
Views: 190

Re: First Test in Discussion

I like to scan or skim the problems that we need to do and see which ones are similar. Usually problems with consecutive numbers are more or less the same (i.e. E7 and E9), so if they are similar, I tend to only do one. I also tend to go for the problems later on in each Fundamentals chapter (i.e. M...
by Jessica Li 4F
Fri Oct 04, 2019 7:51 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 132
Views: 77129

Re: Reading the textbook [ENDORSED]

I used these for my AP Chemistry class in high school, but I think they have some college-level chem as well: https://chem.libretexts.org/ https://www.youtube.com/channel/UCEWpbFLzoYGPfuWUMFPSaoA https://www.youtube.com/watch?v=IFKnq9QM6_A&list=PLJfwA7_CzYE_qLSXH2hJkpffcrc76NjHJ Hope this helps!

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