## Search found 69 matches

Sun Mar 17, 2019 12:26 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Change in Equilibrium Constant
Replies: 2
Views: 332

### Re: Change in Equilibrium Constant

Nope, only temperature can change equilibrium constant.
Sat Mar 16, 2019 3:30 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating Equilibrium Constant (Example 14.8)
Replies: 1
Views: 117

### Calculating Equilibrium Constant (Example 14.8)

Example 14.18 is the following: Screen Shot 2019-03-16 at 3.23.13 AM.png Why is the second half-reaction reversed? I thought that reduction reactions can be identified by the one having the least negative cell potential, and 0.80 is greater than 0.22. Is it because the picture shows that reaction on...
Fri Mar 15, 2019 10:13 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law Problem (8.55 in the Sixth Edition)
Replies: 2
Views: 343

### Hess's Law Problem (8.55 in the Sixth Edition)

I was having trouble with the question below: Screen Shot 2019-03-15 at 10.11.24 PM.png However, when I was computing it, I could not figure out how to cancel oxygen. When I looked at the solutions manual, I don't understand why they multiplied only oxygen by 3/2 in the second equation, but not the ...
Fri Mar 15, 2019 10:09 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Determining Rate Constant (Exercise 15.63, Sixth Edition)
Replies: 5
Views: 178

### Re: Determining Rate Constant (Exercise 15.63, Sixth Edition)

When I input the value of 8.314x10^-3, I get the same answer as the solution manual. However, the solution manual uses 8.314x10^-2 for some reason, and I don't know why. When I plug that value into my work, I get different answers for the whole thing.
Fri Mar 15, 2019 10:05 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: vertical line in cell diagram
Replies: 4
Views: 195

### Re: vertical line in cell diagram

You separate them with a single vertical line when they cannot physically mix together. Because liquids are in contact with each other, they are separated by a comma instead. Solids cannot "mix."
Fri Mar 15, 2019 10:00 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Equation sheet
Replies: 4
Views: 204

### Re: Equation sheet

It's currently on the equation sheet posted on Dr. Lavelle's website, so I would think so.
Fri Mar 15, 2019 9:59 pm
Forum: Student Social/Study Group
Topic: Michelle Nguyen Photos
Replies: 1
Views: 390

### Michelle Nguyen Photos

Congratulations Michelle on your hard work! Here are some pictures I took.
Fri Mar 15, 2019 9:56 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Determining Rate Constant (Exercise 15.63, Sixth Edition)
Replies: 5
Views: 178

### Re: Determining Rate Constant (Exercise 15.63, Sixth Edition)

I think it's supposed to be an equal sign, maybe? The equation for that doesn't involve subtraction.
Fri Mar 15, 2019 9:48 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Determining Rate Constant (Exercise 15.63, Sixth Edition)
Replies: 5
Views: 178

### Determining Rate Constant (Exercise 15.63, Sixth Edition)

Question 15.63 of the sixth edition asks, "The rate constant of the reaction between CO2 and OH- in aqueous solution to give the HCO3- ion is 1.5*10^10 L*mol-1 at 25 degrees celsius. Determine the rate constant at blood temperature 37 degrees celsius, given that the activation energy for the re...
Thu Mar 07, 2019 10:03 pm
Forum: First Order Reactions
Topic: Half life of a first order reaction
Replies: 3
Views: 170

### Re: Half life of a first order reaction

The half life of a first order reaction is dependent only the rate constant, not the initial concentration.
Thu Mar 07, 2019 10:02 pm
Forum: Second Order Reactions
Topic: Final
Replies: 30
Views: 863

### Re: Final

The final is cumulative, so it will cover material from all quarter. I recommend looking over the outlines & doing homework problems!
Thu Mar 07, 2019 10:01 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Rate Orders
Replies: 4
Views: 187

### Re: Reaction Rate Orders

The overall order for a reaction is determined by the combined order of the reactants. In essence, you add up the exponents. Given that rate=k[A]^N*[B]^M*[C]^L, to find the overall order, you add N+M+L. For example, given that rate=k[A]^2[B]^2[C]^-1, the overall order is found by adding up the expon...
Mon Mar 04, 2019 1:22 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Study Advice
Replies: 73
Views: 4015

### Re: Study Advice

I like to go to office hours and workshops. I prefer Lyndon's workshops but it's usually full by 6:15.
Mon Feb 25, 2019 9:25 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing Balanced Equations for Galvanic Cells (14.11 part d sixth edition)
Replies: 3
Views: 126

### Writing Balanced Equations for Galvanic Cells (14.11 part d sixth edition)

Question 14.11 of the sixth edition, part d states: Write the half-reactions and the balanced equation for the cell reaction for each of the following galvanic cells. Pt(s) | O2(g) | H+ (aq) || OH-(aq) | O2(g) | Pt(s). I understand how the anode reaction is derived, but how is the cathode reaction f...
Mon Feb 25, 2019 1:21 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Porous disks
Replies: 1
Views: 65

### Re: Porous disks

Porous disks are used when both electrodes are in the same cell, whereas a salt bridge is used when they are in two separate cells. Ions provided by the electrolyte solutions move between the two compartments to complete the electrical circuit.
Sun Feb 24, 2019 1:27 pm
Forum: Balancing Redox Reactions
Topic: Balancing Half Reactions
Replies: 3
Views: 78

### Balancing Half Reactions

Why is it that we do not need to multiply the standard reduction potential by a coefficient even though the reaction is multiplied by a coefficient? How does this differ from multiplying the reaction by -1 when flipping the reaction?
Sun Feb 24, 2019 1:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert Conductors
Replies: 1
Views: 83

### Inert Conductors

What is the purpose of platinum in the cell diagram Cu(s) | Cu 2+ || Fe3+ (aq), Fe2+ (aq) | Pt(s)? I understand that Pt works as an electrode, but is it the same as the reaction Fe3+ + Cu(s) --> Cu2+ (aq) + Fe2+ (aq), just the Pt is not shown?
Sun Feb 17, 2019 7:49 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Remembering Equations
Replies: 5
Views: 194

### Re: Remembering Equations

Something that helps me is being able to understand what equations are used for. When I am not familiar with equations yet, it is helpful to take an equations sheet and label all equations that I may need to know for that section. Then, when I begin to answer questions, I determine which equation to...
Sun Feb 17, 2019 7:46 pm
Forum: Student Social/Study Group
Topic: absent 2/15
Replies: 3
Views: 152

### Re: absent 2/15

During class, we began to learn about Gibb's Free Energy, specifically using the equation deltaG=H-T*deltaS.
Sun Feb 17, 2019 7:43 pm
Forum: Student Social/Study Group
Topic: Serenade
Replies: 2
Views: 190

### Serenade

Here's another copy of the serenading last week!

https://drive.google.com/file/d/11NSJOI ... sp=sharing
Thu Feb 07, 2019 9:50 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated System
Replies: 4
Views: 131

### Re: Isolated System

An isolated system is one in which neither matter nor energy can be exchanged with its surroundings. Delta U will be 0 because, no matter the amount of time, the change in internal energy cannot be changed in an isolated system.
Thu Feb 07, 2019 3:53 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Change in Internal Energy
Replies: 1
Views: 145

### Change in Internal Energy

I am having trouble with problem 8.25 of the sixth edition. This is the question: A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200 L of solution in the calorimeter (q =-3.50 kJ), resulting in a temperature rise of 7.32 C. In a subseque...
Sat Feb 02, 2019 10:54 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas
Replies: 6
Views: 273

### Re: Inert Gas

Inert gases do not affect equilibrium so long as volume stays constant.
Sat Feb 02, 2019 10:53 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Material on Midterm?
Replies: 9
Views: 388

### Re: Material on Midterm?

I think it will probably go up to what the class website says, up to the end of entropy. Dr. Lavelle is usually pretty good about staying on time with the material and we have until next Wednesday.
Sat Feb 02, 2019 10:51 pm
Forum: Phase Changes & Related Calculations
Topic: PΔV for solids and liquids
Replies: 5
Views: 188

### Re: PΔV for solids and liquids

As others have stated, this equation applies to all phases but the change in liquids and solids are so small that the value is essentially 0.
Mon Jan 28, 2019 1:07 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Question 12.61 (Sixth Edition)
Replies: 2
Views: 447

### Re: Question 12.61 (Sixth Edition)

To start this problem, you would need to convert the pH into molarity by using 10^-4.60. Then, set up an ICE table with the molarity found as the H3O+ equilibrium concentration. Set the initial condition of HClO to x then subtract the molarity found from that, which will be the final equilibrium of ...
Thu Jan 24, 2019 11:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Favoring
Replies: 4
Views: 278

### Equilibrium Favoring

I am working on Module #1 and came across this problem: For the unbalanced reaction, CO (g) + H2 (g) ⇌ CH3OH (g), the equilibrium concentrations are [CO] = 0.0911 M, [H2 ] = 0.0822 M, [CH3OH] = 0.00892 M. What is the value of the equilibrium constant? Does the equilibrium favor reactants or products...
Mon Jan 21, 2019 10:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKa
Replies: 2
Views: 136

### pKa

What is pKa exactly? This is a problem I was working on:

When the pH of 0.10 m HClO2(aq) was measured,
it was found to be 1.2. What are the values of Ka and pKa of chlorous acid?

Why is it that sometimes pKa is equal to pH and other times it is not?
Thu Jan 17, 2019 7:11 pm
Forum: Administrative Questions and Class Announcements
Topic: Posts on Chemistry Community
Replies: 3
Views: 116

### Re: Posts on Chemistry Community

Yes, you need to make three posts (questions, posts, and replies all count!) a week to get your three posts. However, I think if you have 30 posts at the end of the quarter, it should be fine. It all depends on your TA and how they count the posts. To stay safe, I would just make the three posts a w...
Thu Jan 17, 2019 7:08 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: K and Q [ENDORSED]
Replies: 7
Views: 266

### Re: K and Q[ENDORSED]

Both K and Q use the formula [Products]/[Reactants]. However, K is used only when the reaction is at equilibrium. This means that the concentrations of the products and reactants must be at equilibrium (but not necessarily equal to each other!). Q on the other hand can be found at any time of the re...
Thu Jan 17, 2019 6:59 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6th Edition, 12.23
Replies: 2
Views: 365

### Re: 6th Edition, 12.23

I got the same answer as you, 6.83 and I am unsure why the book says 6.80.I think it is a calculation error. In the solutions manual, it states that square root of 2.1x10^-14 is 1.4x10^-7, when I calculated 1.45x10^7. Just to test their answer, I plugged in their value, 1.4x10^-7, to the pH formula....
Sat Jan 12, 2019 1:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q and K
Replies: 13
Views: 343

### Re: Q and K

Q is calculated at any time during the reaction while K is only calculated at equilibrium. This means that Q and K would be equal if the point at which Q was measured was at equilibrium. Q is not limited to the concentration or partial pressures values at equilibrium, while K is.
Sat Jan 12, 2019 1:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc and Kp
Replies: 12
Views: 437

### Re: Kc and Kp

Solids and liquids are not used in equilibrium constants. Kc is used for concentrations while Kp is used for partial pressures. However, these can be converted between each other using the ideal gas law, PV=nRT.
Sat Jan 12, 2019 1:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to use net ionic equation
Replies: 1
Views: 86

### Re: When to use net ionic equation

A net ionic equation is used to determine what has changed in a reaction. If the net ionic equation was not used, spectator ions would be there and have no effect on the reaction; ions would just be "floating around." In essence, you should always strive to use the net ionic equation when ...
Fri Dec 07, 2018 9:17 pm
Forum: Amphoteric Compounds
Topic: Amphoteric compounds
Replies: 2
Views: 134

### Re: Amphoteric compounds

A compound can be amphoteric when it can be an acid or a base. An example of this would be water.
Fri Dec 07, 2018 9:14 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11471

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

Will someone please explain question 40 part B and C For part B: We would expect ozone to have two bond lengths are the same. This is because it is a resonance structure. In resonance structures, the bond lengths are the same--the average of its bond lengths. For part C: O2 would have the strongest...
Fri Dec 07, 2018 9:11 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 11471

### Re: FINAL PRACTICE - Lyndon's Churro Review Session[ENDORSED]

On question 38, how come the LDF’s are the determining factor instead of dipole-dipole in determining the boiling point? H2Se has stronger London dispersion forces, while H2S has stronger dipole-dipole forces. However, because we are given that H2Se has a higher boiling point, all we know that is t...
Fri Dec 07, 2018 1:22 am
Forum: Bronsted Acids & Bases
Topic: Strong Acids vs Weak Acids
Replies: 2
Views: 269

### Re: Strong Acids vs Weak Acids

The properties that make an acid strong are weak are the following: 1. Weaker (longer) A-H bond makes it easier to remove H+. 2. Oxoacids more readily lose H+ if resulting anion is stabilized by electron withdrawing atoms which delocalize and stabilized the negative charge.(Delocalized charge makes ...
Thu Nov 29, 2018 6:43 pm
Forum: Naming
Topic: Brackets in Coordinate Compound Formula
Replies: 2
Views: 83

### Re: Brackets in Coordinate Compound Formula

The formula on the inside of the brackets refers to atoms that are within the coordination sphere and connected to the central atom. Those outside are not.
Thu Nov 29, 2018 12:49 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarizability
Replies: 2
Views: 57

### Re: Polarizability

Polarizability is the characteristic of atoms and ions with electron clouds that readily undergo a large distortion. An anion is highly polarizable if it is large because the nucleus exerts weak control over outermost electrons as they are farther. This makes electron clouds easily distorted.
Thu Nov 29, 2018 12:47 am
Forum: Hybridization
Topic: hybridization notation
Replies: 3
Views: 173

### Re: hybridization notation

When referring to hybridization notation, it does not matter whether it is written 2sp2 or sp2. You would only use 2sp2 when writing the composition of each bond.
Thu Nov 29, 2018 12:44 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 1
Views: 35

### Re: Bond Angles

When we are considering bond angles, we do not take into account bond length. We consider bond length when determining dissociation energy.
Thu Nov 29, 2018 12:40 am
Forum: Dipole Moments
Topic: London Dispersion Forces vs Dipole Dipole
Replies: 3
Views: 475

### London Dispersion Forces vs Dipole Dipole

In the sixth edition, chapter six, question five part c asks, "Suggest, giving reasons, which substance in each of the following pairs is likely to have the higher normal melting point: CHI3 or CHF3." The answer is CHI3 because it has stronger london dispersion forces. Why is it that it is...
Wed Nov 28, 2018 12:38 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge vs Partial charge
Replies: 4
Views: 832

### Re: Formal Charge vs Partial charge

Formal charge is an atom's number of valence electrons minus number of dots and lines, which can more easily be seen in the following equation: an atom's number of valence electron - (number of lone pairs + (number of shared electrons/number of bonds). It is used when drawing Lewis Structures to ens...
Wed Nov 28, 2018 12:25 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: ionic molecule
Replies: 3
Views: 177

### Re: ionic molecule

Yes, all types of molecules have London Dispersion forces.
Sun Nov 18, 2018 6:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: CH2Cl2
Replies: 2
Views: 157

### CH2Cl2

Why is CH2Cl2 polar? When I drew the Lewis structure, I put Cl opposite from each other and I thought that the dipole moments would cancel out, but it is normally drawn with the Cls next to each other. Is there something other than the drawing that makes it polar? How do I know to put them next to e...
Sun Nov 18, 2018 5:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Writing Bond Angles with Multiple Central Angles
Replies: 2
Views: 87

### Writing Bond Angles with Multiple Central Angles

I was doing a problem in which it asks to write the bond angles for C2H4. How do we know which atoms to look at? I understand how we look at H-C-H but how do we know to do H-C-C instead of, say C-C?
Sun Nov 18, 2018 11:58 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle for VSEPR Name AX2E3 [ENDORSED]
Replies: 1
Views: 293

### Bond Angle for VSEPR Name AX2E3[ENDORSED]

Why is it that molecules with an AX2E3 VSEPR name have bond angles of 180 rather than less than 180? I thought that the three lone pairs would cause it to be slightly less than 180.
Sat Nov 17, 2018 5:18 pm
Forum: Hybridization
Topic: Describing Hybridization
Replies: 3
Views: 177

### Re: Describing Hybridization

For a molecule with 4 regions of electron density, you would write the hybridization as sp3. After that, it would be 5=sp3d, 6=sp3d2, etc. Each region can be counted off using one letter.
Thu Nov 15, 2018 10:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Effect of Molecular Shape on Lewis Structure
Replies: 3
Views: 150

### Effect of Molecular Shape on Lewis Structure

When drawing Lewis structures, should we be taking the molecular shapes into consideration?
Thu Nov 15, 2018 6:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Writing VSEPR for (CH3)2Be
Replies: 1
Views: 70

### Writing VSEPR for (CH3)2Be

Hello!

How would one write the VSEPR formula for (CH3)2Be? I have drawn the Lewis structure but I just wanted to check. Would it be broken down for each of the central atoms, or do we consider Beryllium to be the only central atom? Thank you.
Fri Nov 09, 2018 1:39 am
Forum: Ionic & Covalent Bonds
Topic: Polarizability
Replies: 9
Views: 414

### Polarizability

What is polarizability and what is its significance to interactions between ions and molecules?
Fri Nov 09, 2018 1:37 am
Forum: Ionic & Covalent Bonds
Topic: Definition of a Covalent Bond
Replies: 4
Views: 213

### Re: Definition of a Covalent Bond

A covalent bond is a bond between two atoms in which they share an electron. A coordinate covalent bond is a bond in which an atom provides both electrons.
Fri Nov 09, 2018 1:34 am
Forum: Ionic & Covalent Bonds
Topic: Electronegativity values
Replies: 4
Views: 199

### Re: Electronegativity values

We should be given the electronegativities as we are usually not asked to memorize values.
Thu Nov 01, 2018 11:05 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 3
Views: 172

### Re: Ionization Energy

So long as you understand the general trends of ionization energy, I think you should be fine. Though it is not necessary to know the measurements, I believe you can find them in the Appendix.
Thu Nov 01, 2018 6:41 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground State to Ion with D subshell
Replies: 2
Views: 143

### Ground State to Ion with D subshell

Hello, Question 2.47 of the sixth edition asks, "For each of the following ground-state atoms, predict the type of orbital (1s, 2p, 3d, 4f, etc.) from which an electron will be removed to form the +1 ion." Part B asks about Manganese and part D asks about Gold. I was wondering, why it is r...
Thu Oct 25, 2018 9:24 pm
Forum: DeBroglie Equation
Topic: De Broglie module #35
Replies: 3
Views: 236

### Re: De Broglie module #35

Yes, as stated above, while a everything, including a car, has wavelength properties, a car's wavelengths are too small to be detected. The threshold for being detected, as Dr. Lavelle said in class, is about 10^-18 m.
Thu Oct 25, 2018 12:45 am
Forum: Properties of Light
Topic: kg or g [ENDORSED]
Replies: 11
Views: 644

### Re: kg or g[ENDORSED]

Use kg as that is the SI unit. Fun fact: the reason kg the SI unit and not g is simply because a king wanted it that way! Here's the link if you'd like to learn more: https://physics.stackexchange.com/quest ... ic-si-unit
Thu Oct 25, 2018 12:41 am
Forum: Properties of Light
Topic: Using a rounded speed of light in EM problems
Replies: 4
Views: 270

### Re: Using a rounded speed of light in EM problems

Hello! On the formula/constant sheet, speed of light is given as 2.99792*10^8, so I would use that. I don't think it makes that much of a difference but it ensures your answer is precise as possible before rounding off using sig figs.
Thu Oct 18, 2018 11:09 pm
Forum: Properties of Light
Topic: Do I have to memorize the spectrum?
Replies: 20
Views: 816

### Re: Do I have to memorize the spectrum?

I wouldn't think so just because most of our tests are usually on application of content rather than memorization.
Thu Oct 18, 2018 11:08 pm
Forum: Properties of Light
Topic: Speed of Light
Replies: 5
Views: 316

### Re: Speed of Light

As with all problems, it is best to use the number of figures given on the formula sheet. Then round off your sig figs as given in the question to ensure the most accurate answer.
Thu Oct 18, 2018 11:05 pm
Forum: SI Units, Unit Conversions
Topic: How does grading for discussion posts work?
Replies: 80
Views: 3932

### Re: How does grading for discussion posts work?

I was told by my TA that you just have to make three posts. I asked when the end of the week is considered and he told me to have the posts done before Friday's lecture.
Thu Oct 11, 2018 11:39 pm
Forum: Significant Figures
Topic: sig figs in periodic table
Replies: 6
Views: 370

### Re: sig figs in periodic table

I think it is best to use the number of sig figs found in the question. However, when performing the calculations, you should be as exact as possible and use however many figures given on the periodic table. Then, put your answer in sig figs that match the answer.
Thu Oct 11, 2018 11:37 pm
Forum: SI Units, Unit Conversions
Topic: Units
Replies: 8
Views: 362

### Re: Units

I'm not sure if points will be taken down but, personally, it helps me make sure that I am not using incorrect units in a given area. Also, I do believe we get partial credit in places and I think that having units all the way through would ensure you get all the points you deserve.
Thu Oct 11, 2018 11:35 pm
Forum: SI Units, Unit Conversions
Topic: Test and Exam Dates
Replies: 10
Views: 613

### Re: Test and Exam Dates

Yes, as stated above, the midterm is November 5th, while the following test happens the week after Thanksgiving.
Sun Oct 07, 2018 10:56 pm
Forum: Empirical & Molecular Formulas
Topic: Question L39
Replies: 2
Views: 241

### Re: Question L39

Hi!

I was wondering the same thing. The question said it reacted with oxygen in the air and, as oxygen is a diatomic molecule, I assumed we would be using O2 rather than O. I also got the answer of 1:1 ratio. How do we know when to use O2 and when to use O in stoichometry questions?
Thu Oct 04, 2018 6:02 pm
Forum: SI Units, Unit Conversions
Topic: Sig Fig question [ENDORSED]
Replies: 2
Views: 141

### Re: Sig Fig question[ENDORSED]

Yes, I believe you would have to use scientific notation, so in this case, 100 with two sig figs would be 1.0 x 10^2. I believe this is the only way because three sig figs would be 100. (note the period after) or 1.00 x 10^2.
Thu Oct 04, 2018 5:59 pm
Forum: Balancing Chemical Reactions
Topic: Formula for nitric acid
Replies: 3
Views: 199

### Re: Formula for nitric acid

Though we sometimes need them for review problems, I believe he will be giving us the formulas as he told us we would not need to memorize any names. Later on, however, he said we would learn it as we use them more frequently.
Thu Oct 04, 2018 5:56 pm
Forum: Balancing Chemical Reactions
Topic: Extensive v. Intensive Property [ENDORSED]
Replies: 6
Views: 772

### Re: Extensive v. Intensive Property[ENDORSED]

Extensive properties are based on the amount whereas intensive properties do not change with the amount. For example, volume is an extensive property, whereas density is an intensive property. The amount of water does not change the density of water, but the amount of water does change its volume.

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