Search found 61 matches

by megansardina2G
Thu Mar 14, 2019 4:58 pm
Forum: Second Order Reactions
Topic: Half life for second order reaction
Replies: 1
Views: 44

Re: Half life for second order reaction

The half life equation for a second order reaction is: t(1/2) = 1/(K)([A]o) This can be derived from some of the equations that we got in class: t=1/K (1/[A] - 1/[A]o) to get K= 1/(t(1/2))([A]o) and then switch the K and t(1/2) you can also solve for the time it takes for decay that isn't to the hal...
by megansardina2G
Thu Mar 14, 2019 4:50 pm
Forum: General Rate Laws
Topic: intermediate molecules
Replies: 3
Views: 89

Re: intermediate molecules

They are not part of the overall rate law because they are produced in one step and consumed in another, later step.
by megansardina2G
Thu Mar 14, 2019 4:46 pm
Forum: General Rate Laws
Topic: Slowest step
Replies: 1
Views: 46

Re: Slowest step

Similar to when the amount of product produced was based on the limiting reactant, the rate of a reaction is dependent on the slowest step. It doesn't matter how much you change the faster reaction, the slower reaction is still going to be in control because you want to take into account the entire ...
by megansardina2G
Sun Mar 10, 2019 5:50 pm
Forum: General Rate Laws
Topic: Rate Constant
Replies: 1
Views: 45

Re: Rate Constant

No matter what situation, I think the easiest way to determine the units is by looking at the concentrations, since the rate units will always be mol • L-1 • s-1, so whatever leads to that answer multiplied by the concentration's units ends up being k.
by megansardina2G
Sun Mar 10, 2019 5:46 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6th Edition 14.15b
Replies: 1
Views: 38

Re: 6th Edition 14.15b

Reaction: H+ (aq) + OH- (aq) --> H2O (l) Split into reduction and oxidation reactions: H+ is gaining an electron so it is being reduced, OH- is losing an electron so it is being oxidized --> remember OILRIG (oxidation is losing, reduction is gaining) Reduction: 4 H+ + O2 + 4e- --> 2 H2O Oxidation: 4...
by megansardina2G
Sun Mar 10, 2019 4:22 pm
Forum: General Rate Laws
Topic: Writing Rate Laws
Replies: 3
Views: 60

Writing Rate Laws

Why are products never included in rate laws?
by megansardina2G
Sun Mar 03, 2019 10:24 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: pH at 10 C
Replies: 3
Views: 90

Re: pH at 10 C

Pure water is always neutral, since the [H+] and [OH-] concentrations will be equal. If you did that calculation method to get to the pH and it was less than 7, then a pH of 7 would be considered basic. If you got a pH value of greater than 7, then a pH of 7 would be considered acidic. I believe tha...
by megansardina2G
Sun Mar 03, 2019 10:18 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.37
Replies: 1
Views: 51

Re: 14.37

Q has no units (like K) so when you are multiplying and dividing these values, the units end up cancelling out.
by megansardina2G
Sun Mar 03, 2019 10:16 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Question 14.33 Part B (Sixth Edition)
Replies: 1
Views: 52

Re: Question 14.33 Part B (Sixth Edition)

Disproportionation is a chemical reaction where a molecule is transformed into two or more dissimilar products. You can tell if a molecule will disproportionate by looking at the ∆Gº of the reaction. If ∆Gº is positive, then the reaction is not spontaneous, K<1, and reactant formation is favored. If...
by megansardina2G
Sat Feb 23, 2019 11:56 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating enthalpy
Replies: 1
Views: 75

Re: Calculating enthalpy

At constant temperature, ∆H=0, as there is no change, so I'm not sure why you would be asked to calculate ∆H at constant temperature. Under only constant pressure, ∆H = q (you can solve for ∆H using formulas for/with q).
by megansardina2G
Sat Feb 23, 2019 11:46 pm
Forum: Calculating Work of Expansion
Topic: Equations for work
Replies: 7
Views: 271

Re: Equations for work

The first two are the same equation. They are used under constant pressure. (for the second: pressure is constant, so it can be taken outside the integral. The integral of dV is V, and V2-V1 is ∆V, thus the first equation: w=-p∆V) The third equation is used when the reaction is isothermal, but press...
by megansardina2G
Sat Feb 23, 2019 11:42 pm
Forum: Balancing Redox Reactions
Topic: problem 14.5 6th edition
Replies: 1
Views: 43

Re: problem 14.5 6th edition

You can balance the two skeletal equations using H2O, since they are aqueous solutions. The first equation is O3 --> O2 Adding H2O and OH- will balance the oxygens and hydrogens on either side, and then you balance the charge to result in: H2O + O3 + 2e- --> O2 + 2OH- The second equation is Br- --> ...
by megansardina2G
Sun Feb 17, 2019 5:45 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy Trends
Replies: 1
Views: 58

Entropy Trends

Why does the entropy of the universe always increase? Is there some sort of justification? I know that entropy of a system can decrease, but entropy of the universe still increases.
by megansardina2G
Sun Feb 17, 2019 4:06 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Positive Gibbs Free Energy
Replies: 3
Views: 77

Positive Gibbs Free Energy

How are reactions that have a positive ∆G carried out, as they are not spontaneous? (Especially in biological systems)
by megansardina2G
Sun Feb 17, 2019 4:04 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Definition
Replies: 4
Views: 81

Gibbs Free Energy Definition

What is a good definition for “free energy”? I’m a bit confused on what the problems are talking about when the energy is “free”.
by megansardina2G
Sun Feb 10, 2019 1:22 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes
Replies: 11
Views: 401

Re: Phase Changes

Yes, it is important to understand all of the parts of the phase change graph, as when you are changing between multiple phases you have to use each step. For example, if you want to go from solid to gas, you must calculate the total delta H in five steps. the mC(delta T) with the solid specific hea...
by megansardina2G
Sun Feb 10, 2019 1:15 pm
Forum: Calculating Work of Expansion
Topic: Degeneracy
Replies: 3
Views: 75

Re: Degeneracy

Degeneracy is the number of ways of achieving a given energy state. The relationship between degeneracy, W, and entropy, S, is the Boltzmann equation (S = Kb lnW)
by megansardina2G
Sun Feb 10, 2019 1:06 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Value of Variable Kb
Replies: 4
Views: 97

Re: Value of Variable Kb

Kb is Boltzmann's constant. It is provided on the formula sheet.
by megansardina2G
Sun Feb 03, 2019 9:07 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Example 8.6 (6th edition)
Replies: 1
Views: 67

Re: Example 8.6 (6th edition)

There are two parts to the question. Part (a) refers to the constant volume, and part (b) refers to the constant pressure. This results in different changes in temperature, final temperature, and difference changes in internal energy.
by megansardina2G
Sun Feb 03, 2019 9:00 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 8.43 6th edition
Replies: 1
Views: 52

Re: 8.43 6th edition

Hi! So looking at the four graphs, you can solve this mainly by process of elimination. You know that the change in enthalpy for fusion is 10.0 kJ/mol and the change in enthalpy for vaporization is 20.0 kJ/mol. Since the heating rate is constant, the time for fusion (melting) would be twice as fast ...
by megansardina2G
Sun Feb 03, 2019 8:44 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Equipartition Theorem
Replies: 2
Views: 54

Re: Equipartition Theorem

Since it was a part of the syllabus and included in the parts of the textbook to look over/read/do hw problems from, I would assume that we need to at least be familiar with it, although I can't say for sure. Better safe than sorry though!
by megansardina2G
Sun Jan 27, 2019 9:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A19 part c
Replies: 1
Views: 69

Re: 6A19 part c

The solution/solutions manual either added the 10-3 onto the 3.1 or the problem was written so that it accidentally didn't have the 10-3. If it was supposed to be 3.1 and not 3.1x10^3 (as it is in the solutions manual), then the answer should have been 3.2x10^-15. (Basically, something was written i...
by megansardina2G
Sun Jan 27, 2019 9:39 pm
Forum: Phase Changes & Related Calculations
Topic: state properties
Replies: 3
Views: 75

Re: state properties

The easiest and most important thing to remember is that state properties are independent of the path taken (to establish property or value). They depend only on the final and initial values, which are all you need to solve. This is contrasted by path functions (like work and heat), which are depend...
by megansardina2G
Sun Jan 27, 2019 9:25 pm
Forum: Phase Changes & Related Calculations
Topic: State Properites
Replies: 7
Views: 136

Re: State Properites

State properties are quantities that are independent of how a substance was prepared. Work is dependent on path, so it is not a state function. Since work is not a state property/function, heat cannot be either, since the first law of thermodynamics states that the change in the initial energy of a ...
by megansardina2G
Sun Jan 20, 2019 8:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water in ICE tables
Replies: 10
Views: 189

Re: Water in ICE tables

Water is a liquid, which is a pure substance (along with solids); you cannot increase or decrease its concentration. Therefore, liquids are omitted when dealing with equilibrium constants.
by megansardina2G
Sun Jan 20, 2019 7:56 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 12.27 b 6th edition
Replies: 1
Views: 47

Re: 12.27 b 6th edition

Hi! So for part (b), you have to solve for the new concentration in the increased volume flask. c1v1 =c2v2 will help you with this. c1= 0.0250 M, v1=200 mL, c2=?, v2=250 mL. So, c2 = (0.025 x 200)/(250) = 0.020 M. Since the acid is HCl, which is a strong acid, it is completely deprotonated and the m...
by megansardina2G
Sun Jan 20, 2019 7:42 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature's effect on Kc
Replies: 2
Views: 71

Re: Temperature's effect on Kc

K is temperature dependent, so a change in temperature will result in a change in equilibrium (that has to be restored, resulting in a shift in either the forward or backwards direction). For an endothermic reaction, Kc increases with an increase in temperature (and decreases with a decrease in temp...
by megansardina2G
Sun Jan 13, 2019 9:50 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changes in Partial Pressure
Replies: 5
Views: 103

Re: Changes in Partial Pressure

Yes. K does not change when the pressure changes, and since K is temperature dependent you know that the temperature is also constant. Therefore, the volume/concentration has to be the changing factor.
by megansardina2G
Sun Jan 13, 2019 9:47 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing Temperature
Replies: 4
Views: 110

Re: Changing Temperature

Yes, because when the temperature changes the reaction shifts one way or another (endothermic reactions shift towards product formation, exothermic reactions shift toward reaction formation). K is temperature dependent and also changes to reestablish equilibrium, and the concentrations of the reacta...
by megansardina2G
Sun Jan 13, 2019 9:37 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Question 11.77 (Sixth Edition)
Replies: 1
Views: 61

Re: Question 11.77 (Sixth Edition)

A quick way of doing this is determining whether the reaction is endothermic or exothermic. An endothermic reaction favors the formation of products, and an exothermic reaction favors the formation of reactants. Since delta H (enthalpy) is positive for (a), it is endothermic and therefore shifts the...
by megansardina2G
Fri Dec 07, 2018 9:39 pm
Forum: Conjugate Acids & Bases
Topic: Oxoacids
Replies: 2
Views: 200

Re: Oxoacids

Simply speaking, an oxoacid is an acid that contains oxygen. More specifically, it must contain an oxygen, hydrogen, and at least one other element; also, the oxygen has to be bonded to a hydrogen so that it can donate the H+ ion.
by megansardina2G
Fri Dec 07, 2018 9:34 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Chapter 12.51
Replies: 1
Views: 60

Re: Chapter 12.51

When identifying the stronger acid, there are a few things to keep in mind. If there is no oxygen atom, then you judge the non-hydrogen atoms by the weaker bond length. If the central atom is the same and the oxygen atom number is different, the molecule with the higher oxygen atom number will be st...
by megansardina2G
Sun Dec 02, 2018 4:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape in relation to polarity and boiling point
Replies: 5
Views: 157

Re: Molecular shape in relation to polarity and boiling point

If a molecule is polar, it is able to form dipole-dipole intermolecular forces (and possibly hydrogen bonds) in addition to London Dispersion forces. With more forces and bonds, a molecule becomes harder to break, thus causing a higher boiling point to break the bonds and denature the molecule.
by megansardina2G
Sun Dec 02, 2018 4:03 pm
Forum: Naming
Topic: Order of Ligands
Replies: 2
Views: 82

Re: Order of Ligands

I know that, when writing out the compound name, you write the ligands in alphabetical order, so I would stick with that same order for the compound formula. However, I do not think it is as important as writing out the ligands in the name.
by megansardina2G
Sun Nov 25, 2018 11:53 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: text book question 6th edition
Replies: 1
Views: 74

Re: text book question 6th edition

Since iodine is much larger than fluorine and has many more electrons, the London dispersion forces will be much stronger in CHI3 than CHF3. Therefore, CHI3 will have the higher melting point.
by megansardina2G
Sun Nov 25, 2018 11:41 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Bonds
Replies: 3
Views: 83

Re: Bonds

Sigma bonds are always single bonds, or the first bond formed. In bonding pairs that share only a single bond, it will always be a sigma bond. However, if there is a double bond, there will be one sigma bond and one pi bond. Similarly, if there is a triple bond, there will be one sigma bond and two ...
by megansardina2G
Sun Nov 25, 2018 11:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR model
Replies: 4
Views: 98

Re: VSEPR model

Hi! A refers to the central atom of the molecule, X refers to the atoms attached to the central atom in the molecule, and E refers to the lone pairs on the central atom. For example, XeF4 has four bonding pairs and two lone pairs, so it would be AX4E2. Hope this helps!
by megansardina2G
Sun Nov 18, 2018 4:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angle and bond strength
Replies: 4
Views: 104

Re: bond angle and bond strength

Bond angles shouldn't be affected by differing bond strength. For example, a double bond between two atoms is stronger than a single bond, but this won't matter in regards to bond angles and shape. Hope this helps!
by megansardina2G
Sun Nov 18, 2018 3:58 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Nickel Electron Configuration
Replies: 3
Views: 207

Re: Nickel Electron Configuration

The electron configuration for Ni is [Ar]3d^8 4s^2. Focusing on the 3d^8, since the d orbital is able to hold 10 electrons, due to Hund's rule, each electron suborbital has to be filled with one electron before they can double up with opposite spins. Therefore, there are 2 electrons that are unpaire...
by megansardina2G
Sun Nov 18, 2018 3:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: cis and trans dichloroethene
Replies: 3
Views: 68

Re: cis and trans dichloroethene

Hi! The difference between cis-dichloroethene and trans-dichloroethene are the sides on which the chlorine atom is on. In cis-dichloroethene, both chlorine atoms are on the right side of the double bonded carbon atoms, whereas in trans-dichloroethene, one chlorine atom is on the left and one is on t...
by megansardina2G
Thu Nov 08, 2018 7:45 pm
Forum: Ionic & Covalent Bonds
Topic: HW 3.77
Replies: 4
Views: 99

Re: HW 3.77

You look at the differences in electronegativity. In the sixth edition textbook, figure 3.12 shows most of the values you'll need (and all for this problem). Even if you aren't looking at the exact values, you can estimate it using electronegativity trends. Electronegativity increases across a perio...
by megansardina2G
Thu Nov 08, 2018 7:07 pm
Forum: Lewis Structures
Topic: Electron configuration
Replies: 2
Views: 81

Re: Electron configuration

Hi! As you stated, the ground state electron configuration of Cd is [Kr] 4d^10 5s^2. If you want the most likely ion for Cd, you need to take into consideration the electron configurations that are the most stable. The configurations are most stable when the orbitals are either half full or full, so...
by megansardina2G
Thu Nov 08, 2018 6:37 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 3
Views: 61

Re: Polarizability

Polarizability increases with the increase in number of electrons. This is due to the decreased control that the nuclear charge has on the overall charge distribution in the atom. In small atoms, the electron cloud is small and dense, and the electrons have a stronger interaction/attraction with the...
by megansardina2G
Sun Nov 04, 2018 9:07 pm
Forum: DeBroglie Equation
Topic: NUETRON DIFFRACTION [ENDORSED]
Replies: 1
Views: 250

Re: NUETRON DIFFRACTION [ENDORSED]

Neutrons do diffract because they have wavelength properties (like electrons and other particles), as stated in de Broglie's equation.
by megansardina2G
Sun Nov 04, 2018 8:55 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Ideal lewis structure with Formal Charge
Replies: 4
Views: 125

Re: Ideal lewis structure with Formal Charge

Hi! So most of the time, the ideal lewis structure forms when all atoms in the molecule have a formal charge of 0. If this is not possible, then the formal charge should be the lowest possible option (closest to net of 0). When there needs to be a charge, the negative charge should be placed on the ...
by megansardina2G
Thu Nov 01, 2018 12:46 pm
Forum: Trends in The Periodic Table
Topic: Atomic radius across a period
Replies: 3
Views: 115

Re: Atomic radius across a period

All the electrons across a row, or period, are added to the same shell. Protons generally increase at 1:1 ratio with electrons, resulting in a increasing attraction between the electron shells and the nucleus (since the effect of the increasing proton number is not balanced with the effect of the si...
by megansardina2G
Sun Oct 28, 2018 2:09 pm
Forum: Ionic & Covalent Bonds
Topic: The Stronger Bond [ENDORSED]
Replies: 3
Views: 113

Re: The Stronger Bond [ENDORSED]

Covalent bonds (both polar and nonpolar) are stronger than ionic bonds. Unlike the unequal "stealing" of electrons that occurs during ionic bond interactions, covalent bonds share electrons, which provides a more stable molecule with lower potential energy, thus making the bond stronger an...
by megansardina2G
Sun Oct 28, 2018 1:51 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration for Tungsten
Replies: 1
Views: 34

Re: Electron Configuration for Tungsten

The principle quantum number (n) usually determines the order of electron configuration listings, so 4f would be before 5d and 5d would be before 6s. The reason why 5p and 5s are not listed are that they are included in the electron configuration for Xe, so the electron configuration for tungsten wo...
by megansardina2G
Sun Oct 28, 2018 1:45 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy [ENDORSED]
Replies: 7
Views: 187

Re: Ionization Energy [ENDORSED]

Ionization energy can be defined as the amount of energy required to remove one (or more) electron(s) from a neutral atom to form a positively charged ion. This increases across a period due to the increasing number of valence electrons across a period. For example, an alkali metal such as potassium...
by megansardina2G
Sun Oct 21, 2018 9:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 3
Views: 95

Re: Nodal Planes

A nodal plane is an area with zero probability of finding an electron. You should know that the s orbital has 0 nodal planes, the p orbital has 1, the d orbital has 2, and the f orbital has 3. (for planes beyond f, the nodal plane number can be found by n-1).
by megansardina2G
Sun Oct 21, 2018 9:43 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: S,P,D,F
Replies: 6
Views: 2351

Re: S,P,D,F

Hi! The d-orbitals aren't actually labeled with p's like px, py, and pz, since that notation only applies to the p orbitals. (I believe s is different as well, not px) Rather, the five d-orbitals follow this organization: -3 have 4 lobes of electrons located in the xy-, yz-, and zx- planes (dxy, dyz...
by megansardina2G
Sun Oct 21, 2018 9:24 pm
Forum: Properties of Electrons
Topic: Textbook reading Test 2
Replies: 2
Views: 91

Re: Textbook reading Test 2

No, I do not think that we have to read every section in the textbook. Test two covers all the quantum material that we have previously covered in class (as of 10-19-18), which is up to quantum numbers. If we have not covered a part of the material in class, even if it is in the textbook, we do not ...
by megansardina2G
Sun Oct 21, 2018 9:19 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Chapter2, #39, Electron Config. Arrow Graph
Replies: 1
Views: 38

Re: Chapter2, #39, Electron Config. Arrow Graph

HI! So this problem can be solved while referring to section 2.6 of the sixth edition textbook. In (a), the electron configuration represents an excited state. A carbon atom would fill the 1s and 2s orbitals, both with notation ↑↓, and have two electrons in the 2p orbital. This orbital is the focus ...
by megansardina2G
Fri Oct 12, 2018 9:12 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E 27 Sixth Edition
Replies: 2
Views: 294

Re: E 27 Sixth Edition

"Formula units" is simply a term, similar to molecules or atoms. It references to the ions in an ionic compound, whereas "molecule" refers to two or more elements that are covalently bonded. Whether the problem asks for formula units, molecules, or atoms, you will multiply the nu...
by megansardina2G
Fri Oct 12, 2018 9:02 pm
Forum: Properties of Light
Topic: Change in E +/-
Replies: 3
Views: 55

Re: Change in E +/-

I don't think you're missing a specific reason other than frequency, by definition, cannot be negative, since frequency is the number of waves per second. The purpose of the negative sign in this example isn't really about numerical values, but to distinguish between gaining energy (+) and losing en...
by megansardina2G
Fri Oct 12, 2018 8:51 pm
Forum: Quantum Numbers and The H-Atom
Topic: #15 hw
Replies: 1
Views: 44

Re: #15 hw

Hi! So for problem 15, you have to solve for the frequency of the line before you use the Rydberg equation to solve for n2. You already know n1=1, since the line is in the ultraviolet spectrum, and therefore a part of the Lyman series, where n1 always equals 1. (If you want to fact-check this, it ca...
by megansardina2G
Wed Oct 10, 2018 9:45 pm
Forum: Limiting Reactant Calculations
Topic: Test 1
Replies: 8
Views: 524

Re: Test 1

Hi! I took the test on Tuesday (Discussion 3A) and I think that if you worked on the assigned homework problems and successfully completed the post assessment questions on the modules you will be prepared! That is mainly what I did. If you want a little bit more review, I suggest looking over the ex...
by megansardina2G
Wed Oct 03, 2018 5:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Grading for Chemistry Community [ENDORSED]
Replies: 6
Views: 242

Re: Grading for Chemistry Community [ENDORSED]

3 posts per week, for a total of 30 points for 10 weeks. It is posted on the grading section of his syllabus, on the second page.
by megansardina2G
Wed Oct 03, 2018 5:13 pm
Forum: Molarity, Solutions, Dilutions
Topic: Difference between molecules, atoms, and formula units
Replies: 3
Views: 5188

Re: Difference between molecules, atoms, and formula units

I think that, when discussing calculations, the difference between atoms, molecules, and formula units is not important. In any problem that asks you to solve for a certain amount of any of these, you would multiply the number of moles by Avogadro's constant, 6.022 x 10^23. To break down the differe...
by megansardina2G
Wed Oct 03, 2018 4:54 pm
Forum: Molarity, Solutions, Dilutions
Topic: fundamentals e15
Replies: 4
Views: 115

Re: fundamentals e15

For this problem, you are looking for the molar mass of the sulfide of the metal in the compound M(OH)2. The M is unknown, so the first step is to solve for M, or find the metal in the compound. Since the molar mass of this compound is given, you can deduce the metal's molar mass by subtracting the ...
by megansardina2G
Tue Oct 02, 2018 3:04 pm
Forum: Balancing Chemical Reactions
Topic: Problem L.35
Replies: 5
Views: 86

Re: Problem L.35

Hi! The third equation in L35 in my textbook was given as: Fe3Br8 + Na2CO3 -----> NaBr + CO2 + Fe3O4 (I have the sixth edition textbook, but I think the equation should be the same for this problem, even if you have the seventh) The equation that you wrote down in your question had FeBr2 in place of...

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