Search found 60 matches

by Jessica Castro 2H
Sat Mar 16, 2019 9:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 4
Views: 61

Re: Galvanic Cells

The cathode is where the reduction reaction occurs (usually on the right side) whereas the anode is where the oxidation reaction occurs (usually on the left.
by Jessica Castro 2H
Sat Mar 16, 2019 9:30 pm
Forum: First Order Reactions
Topic: units
Replies: 3
Views: 186

Re: units

1st order k units are s^-1
2nd order k units are L/mol/s
0 order k units are mol/L/s
by Jessica Castro 2H
Sat Mar 16, 2019 9:16 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation
Replies: 2
Views: 164

Re: Nernst Equation

We would use this to determine the cell potential when the cell is not in standard conditions.
by Jessica Castro 2H
Sat Mar 16, 2019 11:18 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Midterm Questions
Replies: 2
Views: 168

Re: Midterm Questions

Since the sample is brought to a pH of 6.1, the pH describes [H3O+] at equilibrium, NOT the initial concentration. Therefore, we can infer that the sample is at equilibrium and we can calculate [CO2] directly from K = [CO2]/[H3O+][HCO3-].
by Jessica Castro 2H
Fri Mar 15, 2019 9:58 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy
Replies: 2
Views: 161

Re: Gibbs Free Energy

Yes, a equilibrium, since both the forward and reverse reactions are occurring at the same rate, K = 1. Therefore, looking at the equation ΔG°= =RTlnK, plugging in K=1 would result in ΔG°= 0. Thinking at it conceptually, since both the forward and reverse reactions are occurring at the same rate, Gr...
by Jessica Castro 2H
Fri Mar 15, 2019 9:53 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Ideal Gas
Replies: 1
Views: 188

Re: Ideal Gas

Cp is used when pressure is constant (isobaric) and Cv is used when volume is constant (isochoric).
by Jessica Castro 2H
Fri Mar 15, 2019 9:51 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Oxidizing Power - Test 2
Replies: 2
Views: 56

Re: Oxidizing Power - Test 2

Since the question was asking for reducing power and the standard potentials for the reduction reactions were given, you did not need to flip the signs.
by Jessica Castro 2H
Fri Mar 15, 2019 9:27 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Delta G of galvanic cells
Replies: 2
Views: 164

Re: Delta G of galvanic cells

A galvanic cell by definition is an electrochemical cell in which a spontaneous chemical reaction is used to generate an electric current. Since the chemical reaction in a galvanic cell is always spontaneous, delta G will always be negative for a galvanic cell.
by Jessica Castro 2H
Fri Mar 15, 2019 9:22 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: formulas that we need to know by heart?
Replies: 1
Views: 40

Re: formulas that we need to know by heart?

I don't think he expects us to memorize these formulas, however, it is good to know how to derive these equations from the ones given on the equation sheet: For ln(K2/K1) = -delta H/R(1/T2 - 1/T1), we can equate the two equations given for standard Gibbs free energy ΔG°= -RTlnK and ΔG°= ΔH°-TΔS° and...
by Jessica Castro 2H
Fri Mar 15, 2019 8:56 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: homework problem 15.61
Replies: 1
Views: 40

Re: homework problem 15.61

I'm sure either is fine, as long as you are consistent throughout the problem.
by Jessica Castro 2H
Fri Mar 15, 2019 8:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Ecell
Replies: 4
Views: 76

Re: Ecell

When adding the Ecells of both reactions, we need to make sure that the electrons will cancel because we don't want electrons in the overall reaction. This is done by multiplying the equations by a least common multiple and by flipping one of the reactions so the electrons will cancel. By doing this...
by Jessica Castro 2H
Fri Mar 15, 2019 8:37 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre-equilibrium approach
Replies: 2
Views: 45

Re: Pre-equilibrium approach

Since K is unitless, it is better to try to replace K with k/k' when possible to be consistent with units. It is also easier to understand the concentrations of the reactants when k is used instead of K.
by Jessica Castro 2H
Thu Mar 14, 2019 10:43 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: catalyst vs intermediate
Replies: 9
Views: 136

Re: catalyst vs intermediate

In a series of reactions, you will always start with the catalyst as a reactant. In contrast, an intermediate is first introduced as a product because an intermediate is formed then used.
by Jessica Castro 2H
Mon Mar 11, 2019 5:52 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta U
Replies: 5
Views: 199

Re: Delta U

Since internal energy (U) depends on temperature, in an isothermal process where temperature does not change internal energy will not change either. Therefore, delta U = 0 for an isothermal process.
by Jessica Castro 2H
Mon Mar 11, 2019 3:17 pm
Forum: First Order Reactions
Topic: Problem 7B.1 7th edition
Replies: 1
Views: 42

Re: Problem 7B.1 7th edition

For first order reactions, the equation for the plot is ln[A] = -kt + ln[A]0. If you solve for kt you would get kt = ln[A]0 - ln[A]. We know that for subtraction with ln, lnx -lny = ln(x/y). Therefore, kt = ln[A]0 - ln[A] = ln([A]0/[A]). There should be an ln next to the [A]0, but both equations sho...
by Jessica Castro 2H
Fri Feb 08, 2019 2:05 am
Forum: Calculating Work of Expansion
Topic: 4F.1 7th Edition
Replies: 4
Views: 86

Re: 4F.1 7th Edition

The amount of heat given is the heat generated by your body (which is the system). The question is asking for the entropy of the surroundings. Therefore, when plugging in the heat of the surroundings, remember q system = - q surroundings. The heat of a system is equal and opposite to the heat of its...
by Jessica Castro 2H
Fri Feb 08, 2019 2:00 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Knowing which one to use
Replies: 3
Views: 102

Re: Knowing which one to use

Heat capacity (C) is simple the heat supplied / change in temp (C = q / delta T). Specific heat capacity (Cs) is the heat capacity at a given mass (Cs = C/m), therefore q = m x Cs x delta T. Molar heat capacity (Cm) is the heat capacity at a given amount of moles (Cm = C/n), therefore q = n x Cm x d...
by Jessica Castro 2H
Thu Feb 07, 2019 11:13 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Units for Entropy
Replies: 3
Views: 90

Re: Units for Entropy

Remember that change in entropy is the heat at a constant temperature (delta S = q / t). Therefore the units will be the units of heat (J) over the units of temperature (Kelvin) --> J/K. It is in Kelvins because that is the absolute temperature.
by Jessica Castro 2H
Thu Feb 07, 2019 11:10 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Thermodynamic Property
Replies: 1
Views: 63

Re: Thermodynamic Property

Thermodynamic properties refer to how the system exists, whether it can exist at any point in space regardless of how much or if it changes based on how much is in the system (the mass of the system). These are broken up into intensive and extensive properties. Intensive properties exist anywhere in...
by Jessica Castro 2H
Thu Feb 07, 2019 10:52 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy with change in pressure
Replies: 1
Views: 45

Re: Entropy with change in pressure

You can use the relationship between pressures and volumes (P1V1 = P2V2) and manipulate it to get (P1/P2 = V2/V1). Then just substitute P1/P2 into delta S = nRln(V2/V1).
by Jessica Castro 2H
Thu Feb 07, 2019 10:48 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Internal Energy, Enthalpy, and Heat
Replies: 2
Views: 59

Re: Internal Energy, Enthalpy, and Heat

Internal energy is the amount of energy that exists in the system based on its chemical properties, basically the potential energy. Heat is a measure of energy transferred as temperature changes. Enthalpy is the change in heat of a reaction at constant pressure. Hope this helps.
by Jessica Castro 2H
Thu Feb 07, 2019 10:37 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Change in entropy and its relation with temperature
Replies: 2
Views: 62

Re: Change in entropy and its relation with temperature

Looking at the equation for the change in entropy (delta S = q / T), we can see that temperature (T) is inversely related with the change in entropy (delta S). Therefore, at lower temperatures, there will be a greater change in entropy. Looking at the concept of entropy conceptually, entropy changes...
by Jessica Castro 2H
Thu Feb 07, 2019 10:24 pm
Forum: Phase Changes & Related Calculations
Topic: Problem 4A7 7th edition
Replies: 1
Views: 42

Re: Problem 4A7 7th edition

For part b, it is asking what percentage of the total heat was used to specifically heat the water. Therefore, we need to divide the heat of water by the total heat used (Q of water / Q total) and multiply by 100 to find the percentage. I think we use the info from the table to find the heat used fo...
by Jessica Castro 2H
Thu Feb 07, 2019 10:18 pm
Forum: Calculating Work of Expansion
Topic: L*atm conversion to Joules
Replies: 2
Views: 65

Re: L*atm conversion to Joules

The standard units for Rydberg's constant are J/K/mol. But if you need to use pressure in your equation, the conversion is 1 L atm = 101.325 J
by Jessica Castro 2H
Mon Jan 28, 2019 11:45 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 7th Ed. 4C3
Replies: 2
Views: 59

7th Ed. 4C3

I'm not sure if I'm doing this problem right. I first found Cpm (Cvm for b) then found delta T then added that to the intial T to find the temperature. Then for change in enthalpy, since it equals the heat in constant pressure, I just used the given heat. However, the answer it doesn't match the ans...
by Jessica Castro 2H
Mon Jan 28, 2019 11:18 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Thermal Equilibrium
Replies: 5
Views: 102

Re: Thermal Equilibrium

"Molecular processes" is referring to the transfer of energy as heat between the system and the surroundings. Therefore, at thermal equilibrium, energy is being transferred between the system and its surroundings at the same rate.
by Jessica Castro 2H
Mon Jan 28, 2019 11:15 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Problem 4A.13 7th Edition
Replies: 2
Views: 72

Re: Homework Problem 4A.13 7th Edition

The first step would be to solve for Ccal. Since q = -Ccal (delta T), solving for Ccal = -q(deltaT). Since q = -3.5kJ, we would end up with a positive Ccal. Then use Ccal to find qcal. Then recall that q reaction + q cal = 0, therefore q reaction = - q cal.
by Jessica Castro 2H
Mon Jan 28, 2019 10:53 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 7th Edit 4A7
Replies: 2
Views: 45

Re: 7th Edit 4A7

For this problem, we are looking for the total heat (Q total)for the whole process. To find Q total, we need to find the heat for both copper and and water. Use the respective values for copper and water to find Q copper and Q water. Then add Q copper and Q water to find the Q total.
Hope this helps!
by Jessica Castro 2H
Sun Jan 13, 2019 10:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium K expression
Replies: 1
Views: 30

Re: Chemical Equilibrium K expression

The K expression only applies to substances that change in concentration, which affect the reactant at equilibrium. Since solids and liquids have a constant concentration during the reaction, they do not affect the amount of reactant at equilibrium. Therefore, we can ignore solids and liquids when f...
by Jessica Castro 2H
Sun Jan 13, 2019 10:48 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic and Endothermic Reactions
Replies: 1
Views: 49

Re: Exothermic and Endothermic Reactions

It doesn't say on Lavelle's outline that we are required to know the energy profile diagrams. However, I think it's best to have an understanding of what the graph would look like based on the direction of the reaction and vice versa and be able to relate the two.
by Jessica Castro 2H
Sun Jan 13, 2019 10:29 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q
Replies: 2
Views: 61

Re: Q

If we compare K and Q when the temperature changes, then we can also use Q to determine whether the reaction is endothermic or exothermic based on the direction of the reaction. For example, if the reaction shifts right (favors product), then the reaction requires heat, therefore the reaction is end...
by Jessica Castro 2H
Sat Dec 08, 2018 11:02 pm
Forum: Hybridization
Topic: Hybridization Naming
Replies: 2
Views: 205

Re: Hybridization Naming

In class, I remember Lavelle saying either way is fine. However, on m midterm, I put d ahead of s and my TA drew an arrow to put it after p. So just in case, put it in spd order.
by Jessica Castro 2H
Sat Dec 08, 2018 11:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw and t shape angles
Replies: 2
Views: 116

Re: Seesaw and t shape angles

For a molecule whose shape is seesaw, it's arrangement of electrons is trigonal bypyramidal. In a trigonal bipyramidal shape, we have angles 90, 120, and 180 degrees. When we make one of the bonds on the equatorial in a trigonal bypyramidal shape a lone pair, all the angles are less than the origina...
by Jessica Castro 2H
Sat Dec 08, 2018 10:53 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: H Bonds stronger than dipole-dipole
Replies: 2
Views: 2170

Re: H Bonds stronger than dipole-dipole

Dipole-dipole interactions are electrostatic interactions between any partially negative atom and any partially positive atom. However, a hydrogen bond is specifically between a partially positive hydrogen atom and a partially negative atom (N, O, or F). Since N, O, and F, are much more electronegat...
by Jessica Castro 2H
Sat Dec 08, 2018 10:45 pm
Forum: Calculating the pH of Salt Solutions
Topic: Salt Solution pH — 7th Edition 6.D.11
Replies: 2
Views: 204

Re: Salt Solution pH — 7th Edition 6.D.11

Someone had the same question, so here's what I told them.

F is an exception to this rule, in that F is the only halogen that does affect the pH of a solution. Since KF is a very weak acid, the conjugate base of KF is a basic solution, therefore producing a pH greater than 7.
by Jessica Castro 2H
Sat Dec 08, 2018 10:41 pm
Forum: Identifying Acidic & Basic Salts
Topic: Homeword 6D11 7th edition
Replies: 2
Views: 179

Re: Homeword 6D11 7th edition

F is an exception to this rule, in that F is the only halogen that does affect the pH of a solution. Since KF is a very weak acid, the conjugate base of KF is a basic solution, therefore producing a pH greater than 7.
by Jessica Castro 2H
Sat Dec 08, 2018 10:35 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: Hydrogen Bonding
Replies: 5
Views: 253

Re: Hydrogen Bonding

It depends whether or not a hydrogen can form a hydrogen bond. For hydrogens, they must be partially positive to form a hydrogen bond (with N, O, or F). For example, the hydrogens in methane (CH4) have no partial charge. Therefore, they can't form hydrogen bonds. Since oxygen is a very electronegati...
by Jessica Castro 2H
Sat Dec 08, 2018 10:27 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 7
Views: 317

Re: Cisplatin

DNA is held by hydrogen bonds. Therefore, for something to bind to it, it must also bind to a polar molecule (bonded by hydrogen bonds). Since cisplatin has its two chlorines on the same side, the dipole doesn't cancel, creating partial negative charges on the chlorines. This allows cisplatin to bin...
by Jessica Castro 2H
Sat Dec 08, 2018 10:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polarity
Replies: 2
Views: 107

Re: polarity

Polarity is also determined on whether or not the dipoles cancel. Tip: try to know the trend of electronegativity to determine if a dipole exists or not.

Example: XeF4 has two lone pairs, but the two lone pairs cancel. Therefore XeF4 is nonpolar.

Hope this helps!
by Jessica Castro 2H
Sat Dec 08, 2018 10:17 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Homework 6C.17
Replies: 1
Views: 42

Re: Homework 6C.17

My logic for this problem was to see which molecule is more likely to disassociate and accept protons. Since BrO^- has an extra electron on O, we can infer that O will want to form a bond with H+. If we write out the equation, we can see that OH- will form and Br- will be left alone, making BrO- the...
by Jessica Castro 2H
Tue Nov 13, 2018 11:46 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: Lewis Structures before Forces?
Replies: 2
Views: 61

Re: Lewis Structures before Forces?

Drawing the Lewis structure is your best guide. Once you draw it out, use your knowledge about polarizability and electronegativity to determine the distribution of charge and the type of intermolecular force.
by Jessica Castro 2H
Tue Nov 13, 2018 11:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Remembering
Replies: 8
Views: 170

Re: Remembering

An easy way to do a VSEPR model is to start with the Lewis structures. Don't forget about formal charge. Once you have your designated lone pairs about the central atom, treat them as an area of high electron concentration, then space out all areas of high electron concentration away from each other...
by Jessica Castro 2H
Tue Nov 13, 2018 11:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis Structures/Shape
Replies: 3
Views: 73

Re: Lewis Structures/Shape

In respect to the 2 carbon atoms the shape will be tetrahedral.
by Jessica Castro 2H
Sun Nov 04, 2018 10:06 pm
Forum: Lewis Structures
Topic: Lewis Structure for Ammonium chloride
Replies: 3
Views: 343

Re: Lewis Structure for Ammonium chloride

By calculating the formal charge of each atom, we can tell that this is an ionic bond. Remember in ionic bonds, the valence electrons are TRANSFERRED, while in covalent bonds, the atoms are shared. That is why in this ionic bond, ammonium (the cation) and chloride (the anion) are not connected.
by Jessica Castro 2H
Sun Nov 04, 2018 10:01 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 5
Views: 118

Re: Electronegativity

Electronegativity measures an atom's affinity or attractiveness to electrons. The more electronegative an atom is, the greater the pull of electrons is towards the atom's nucleus. I like to think of a tug of war. Let the middle of the rope represent the valence electrons in the bond. Electronegativi...
by Jessica Castro 2H
Sun Nov 04, 2018 10:00 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 5
Views: 118

Re: Electronegativity

Electronegativity measures an atom's affinity or attractiveness to electrons. The more electronegative an atom is, the greater the pull of electrons is towards the atom's nucleus. I like to think of a tug of war. Let the middle of the rope represent the valence electrons in the bond. Electronegativi...
by Jessica Castro 2H
Sun Nov 04, 2018 9:49 pm
Forum: Lewis Structures
Topic: double bonds
Replies: 2
Views: 38

Re: double bonds

Yes, when oxygen is present, it is the atom that typically forms double bonds because looking for two more valence electrons. The number of bonds an atom can form is based on the number of valence electrons it needs to have a full octet.
by Jessica Castro 2H
Sun Oct 28, 2018 5:42 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 7th edition 2A.9 and 2A.11
Replies: 2
Views: 90

Re: 7th edition 2A.9 and 2A.11

All this question is asking is which atom (of ^+2, which will make it an ion-cation) has the given configuration? However, remember: each orbital contains a pair of (2)electrons, so if the ion contains a charge greater than 2 (i.e. +3 charge), it will likely be referring to the atom in the next orbi...
by Jessica Castro 2H
Sun Oct 28, 2018 5:31 pm
Forum: Ionic & Covalent Bonds
Topic: the Octet rule
Replies: 21
Views: 431

Re: the Octet rule

Most elements try to follow the Octet Rule in order to obtain a more stable state. However, as Dr. Lavelle mentioned during lecture, Hydrogen, Helium, Lithium, and Beryllium are exceptions to the Octet Rule because they don't have enough electrons in which obtaining 8 valence electrons would make th...
by Jessica Castro 2H
Sun Oct 28, 2018 5:27 pm
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 8
Views: 113

Re: Lewis Structures

The number of dots around the nuclear symbol of an element corresponds with its number of valence electrons. Tip: Remember that for all elements (except for hydrogen and helium), the outer shell would fill up to 8 valence electrons. However, always start with one on each side (the first 4), then pai...
by Jessica Castro 2H
Sat Oct 20, 2018 10:39 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Coulomb's Law
Replies: 3
Views: 62

Re: Coulomb's Law

Coulomb's Law represents the effect of inter nuclear distance on the electrostatic potential energy of the charges between non H- atoms. This equation shows that the electrostatic potential energy and the inter nuclear distance between the charges are inversely proportional.
by Jessica Castro 2H
Sat Oct 20, 2018 10:27 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Q 42 on post assessment
Replies: 5
Views: 98

Re: Q 42 on post assessment

I believe you would use the equation for the energy level of an H- atom, but use it for the initial and final n. In this case, you would be solving for n(initial). Set this difference equal to the equation for the energy of a photon, since it takes energy to change from one energy level to another.
by Jessica Castro 2H
Sat Oct 20, 2018 10:19 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Alternate names of n, l, ml, and ms
Replies: 2
Views: 107

Re: Alternate names of n, l, ml, and ms

Just a note: The name for the quantum number and what the quantum number describes is not the same thing. (n) can be called the shell or the principle quantum number. It describes the energy level and size of the atom. (l) can be called the subshell or the angular momentum quantum number. It describ...
by Jessica Castro 2H
Sat Oct 20, 2018 10:05 pm
Forum: Properties of Light
Topic: De Broglie's equation [ENDORSED]
Replies: 7
Views: 446

Re: De Broglie's equation [ENDORSED]

De Broglie's equation can only be used for particles with rest mass. Since photons are massless, this equation does not apply for light.
by Jessica Castro 2H
Thu Oct 11, 2018 10:03 pm
Forum: Properties of Electrons
Topic: wavelength and ounces
Replies: 4
Views: 121

Re: wavelength and ounces

Convert the weight of the baseball to kg and the velocity to m/s, then use the equation for wavelength we learned in class.
by Jessica Castro 2H
Thu Oct 11, 2018 9:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: shells versus orbitals
Replies: 3
Views: 232

Re: shells versus orbitals

The number of shells and orbitals depend on the number of electrons of the atom, thus the energy level of the atom. Shells (represented by circles around the nucleus of an atom), represent the energy levels of an atom. The energy levels are labeled by n, with a number in front to represent which ene...
by Jessica Castro 2H
Thu Oct 11, 2018 9:37 pm
Forum: Properties of Light
Topic: Wavelength
Replies: 10
Views: 112

Re: Wavelength

Since most other units that contain a measurement of length (i.e. velocity is m/s, etc.), it is best to convert measures of length into meters (m). On another note, most units are calculated using the SI units. Unless the given values and the other needed units are not in SI units, it is best to con...
by Jessica Castro 2H
Wed Oct 03, 2018 11:29 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals E3- 7th Edition
Replies: 3
Views: 66

Re: Fundamentals E3- 7th Edition

From the book, we know that the mass of a molecule equals the number of atoms multiplied by the number of atoms (m=nM). If we solve for gallium's and astatine's mass using their respective molar masses and Avogadro's number, we compare the two to see how to make them equal (multiply by 3). By gettin...
by Jessica Castro 2H
Mon Oct 01, 2018 11:59 pm
Forum: SI Units, Unit Conversions
Topic: Week 1 Homework Assignment [ENDORSED]
Replies: 16
Views: 461

Re: Week 1 Homework Assignment [ENDORSED]

I talked to one of the TAs and she said that they will be grading the homework based on picking problems that are relevant to the material that was taught that week and trying your best to complete them correctly and understand the concepts of each problem. Also, I suggest doing more than 7 problems...
by Jessica Castro 2H
Mon Oct 01, 2018 11:55 pm
Forum: Empirical & Molecular Formulas
Topic: Chemical Equations?
Replies: 4
Views: 185

Re: Chemical Equations?

The coefficients in a chemical equation represent the ratio of moles required among molecule for the reaction to occur. They do not represent the actual number of moles. Also, remember that moles are a representation of a number (i.e. a dozen = 12, whereas 1 mole = 6.022 x 10^23).

Go to advanced search