Search found 71 matches

by Hailey Qasawadish 2J
Wed Dec 16, 2020 11:22 pm
Forum: General Science Questions
Topic: atomic radius
Replies: 7
Views: 53

Re: atomic radius

You have to look at this question from the point of effective nuclear charge. Cl- is bigger because of the extra electron.
by Hailey Qasawadish 2J
Wed Dec 16, 2020 9:47 am
Forum: Properties of Light
Topic: Wavelength
Replies: 26
Views: 183

Re: Wavelength

You always want to base your answer off of what the question is asking for, but in order to do calculations, most have to be done with the units in meters.
by Hailey Qasawadish 2J
Sat Dec 12, 2020 3:10 pm
Forum: Conjugate Acids & Bases
Topic: sapling question 14
Replies: 7
Views: 55

Re: sapling question 14

If the pH is lower than the pka then it will be neutral, this is because the solution is more acidic than the actual acidity of the weak acid. Therefore, the acid will protonate and keep its proton. If the pH is bigger than the pKa, the solution is more basic so the weak acid will deprotonate and g...
by Hailey Qasawadish 2J
Fri Dec 11, 2020 9:25 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating Ligands vs Polydentate ligands
Replies: 5
Views: 35

Re: Chelating Ligands vs Polydentate ligands

They aren't necessarily the exact same, but a polydentate ligand forms a ring, or rather, chelates, meaning that polydentate ligands are cheating ligands.
by Hailey Qasawadish 2J
Fri Dec 11, 2020 9:23 pm
Forum: Naming
Topic: Ferrate for iron
Replies: 5
Views: 47

Re: Ferrate for iron

There is a really good table listed in the textbooks that has the common ligands listed that we should memorize. I believe it is called "Table 9C.1" in the textbook!
by Hailey Qasawadish 2J
Fri Dec 11, 2020 9:19 pm
Forum: Amphoteric Compounds
Topic: memorizing amphoteric oxides
Replies: 3
Views: 50

Re: memorizing amphoteric oxides

Yes, we are supposed to memorize them. In Matthew Tran's workshop, he explained that a metal oxide is usually a base, a nonmetal oxide is usually an acid, and a transition metal oxide is usually an amphoteric compound. The amphoteric compounds generally follow the diagonal line of the metalloids.
by Hailey Qasawadish 2J
Fri Dec 11, 2020 9:16 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids
Replies: 8
Views: 64

Re: Strength of Acids

You can only use the size of the atom to determine the relative acidity of two atoms bonded together, for example, HF vs HCl. Since Cl is bigger than F, the bond between HCl is longer and weaker than the bond between HF. Thus, the weaker bond is easier to break and the acid is stronger. When you hav...
by Hailey Qasawadish 2J
Sat Dec 05, 2020 5:25 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Energy levels
Replies: 4
Views: 53

Re: Energy levels

You should get the same answer either way! Maybe you made a calculation error somewhere? Or maybe you have the final and initial mixed up? If you want to include your work in this post, maybe we can find where it went wrong!
by Hailey Qasawadish 2J
Sat Dec 05, 2020 5:14 pm
Forum: Naming
Topic: Order of Ligands/naming
Replies: 28
Views: 141

Re: Order of Ligands/naming

As others have said, you write them in alphabetical order. And, you do not apply the prefixes when looking at the alphabetical order.
by Hailey Qasawadish 2J
Sat Dec 05, 2020 5:09 pm
Forum: Naming
Topic: what does (en) mean?
Replies: 23
Views: 163

Re: what does (en) mean?

Adding on to what everyone said above, there are some really helpful tables in the textbook under the 9C section that outline common ligands! They're really helpful when trying to memorize all of the different ones. But, as others have said, en is a bidentate ligand that is short for ethylenediamine!
by Hailey Qasawadish 2J
Sat Dec 05, 2020 5:07 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: ligand names
Replies: 10
Views: 68

Re: ligand names

Hi! There are some really helpful diagrams and tables in the textbook under the 9C section. I do think it's a good idea to memorize most of the ligands as we won't be able to use additional resources on the exam.
by Hailey Qasawadish 2J
Sat Dec 05, 2020 5:05 pm
Forum: Ionic & Covalent Bonds
Topic: Polar and Nonpolar
Replies: 28
Views: 176

Re: Polar and Nonpolar

I also like to see what the shape is in order to determine if it is polar or nonpolar. A lot of times, you can determine polarity by looking at if there are lone pairs or not. If there are lone pairs, it is usually polar.
by Hailey Qasawadish 2J
Sat Dec 05, 2020 4:34 pm
Forum: Naming
Topic: Naming H2O
Replies: 11
Views: 88

Re: Naming H2O

I have seen it be done both ways in the book, but I don't think it matters too much. I think writing it as OH2 is just a little bit more specific in terms of bonding.
by Hailey Qasawadish 2J
Fri Dec 04, 2020 7:00 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Molecular Geometry vs. Electron Geometry
Replies: 6
Views: 36

Re: Molecular Geometry vs. Electron Geometry

You are correct that you only consider the bonds when determining the molecular geometry. And the shape of the molecule is just another name for molecular geometry. As for electron geometry, Dr. Lavelle often referred to it as "the arrangement of electron density," but they both mean the ...
by Hailey Qasawadish 2J
Fri Dec 04, 2020 2:52 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Molecular Geometry vs. Electron Geometry
Replies: 6
Views: 36

Molecular Geometry vs. Electron Geometry

I was a little confused about when I am supposed to include the number of lone pairs when determining the shape/geometry. From my understanding, molecular geometry only considers the bonds, whereas electron geometry considers the lone pairs as well. Though, on some of the sapling questions/textbook ...
by Hailey Qasawadish 2J
Sat Nov 28, 2020 9:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 17
Views: 75

Re: Polarity

Hi! To know if a molecule is polar, you would look to see if the dipoles do not cancel, or rather, if there was an unequal sharing of electrons. As a general rule, when a molecule has lone pairs on the central atom, it is polar. You also want to look at the symmetry of the molecule. If it is symmetr...
by Hailey Qasawadish 2J
Sat Nov 28, 2020 9:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: pi and sigma bonds
Replies: 17
Views: 97

Re: pi and sigma bonds

You want to look at how many single, double, or triple bonds a molecule has. Each single bond is a sigma bond, and each double bond is one sigma bond and one pi bond, and each triple bond is one sigma bond and 2 pi bonds. Hope this helps!
by Hailey Qasawadish 2J
Sat Nov 28, 2020 7:10 pm
Forum: Lewis Structures
Topic: Angles and Respulsion
Replies: 2
Views: 28

Re: Angles and Respulsion

Hi! Bond angles are usually affected by whether or not a lone pair is present on the central atom. If there is a lone pair, it will try to repel the bonded pair of electrons due to the sharing of electrons between the bond. Because of this, the bond angle is decreased. Therefore, the bond angle is d...
by Hailey Qasawadish 2J
Sat Nov 28, 2020 7:07 pm
Forum: Student Social/Study Group
Topic: Finals!
Replies: 43
Views: 348

Re: Finals!

705512695 3K wrote:Will the final have more new material or will it be a balance of the whole year?

I'm assuming the final would focus more on new material as we have already been tested on the older stuff, but I'm not 100% sure!
by Hailey Qasawadish 2J
Sat Nov 28, 2020 7:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity and Shape
Replies: 13
Views: 91

Re: Polarity and Shape

You can figure out if a molecule is polar or nonpolar by looking at if the dipoles cancel or not. If they do, it is nonpolar, and if they don't, it is polar. As a general rule, if the molecule has lone pairs, the molecule will be polar. Hope this helps!
by Hailey Qasawadish 2J
Sat Nov 28, 2020 7:04 pm
Forum: Lewis Structures
Topic: determining polarity
Replies: 5
Views: 42

Re: determining polarity

To determine polarity, you want to pay attention to the dipole moments to see if they cancel out or not. If they do cancel, the bond is nonpolar. But if there is an unequal sharing, meaning the dipole moments don't cancel, the bond is polar. If one bond is polar, the entire molecule is polar. Anothe...
by Hailey Qasawadish 2J
Sat Nov 28, 2020 6:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: using VSEPR
Replies: 4
Views: 22

Re: using VSEPR

You would want to look at the number of lone pairs. This will help you find the shape as well as the bond angles. Hope this helps!
by Hailey Qasawadish 2J
Sun Nov 22, 2020 10:01 pm
Forum: Dipole Moments
Topic: Dipole-Dipole
Replies: 10
Views: 42

Re: Dipole-Dipole

As a general rule, polar molecules have dipole dipole interactions because there is an unequal sharing of electrons causing a dipole moment. Hope this helps!
by Hailey Qasawadish 2J
Sun Nov 22, 2020 9:59 pm
Forum: Trends in The Periodic Table
Topic: Ionic Character
Replies: 11
Views: 93

Re: Ionic Character

You can determine ionic character by looking at electronegativity value differences. The higher the electronegativity difference, the more ionic the character is. Another way to tell is the most ionic are usually furthest apart on the periodic table.
by Hailey Qasawadish 2J
Sun Nov 22, 2020 10:38 am
Forum: Ionic & Covalent Bonds
Topic: Polar/ Nonpolar
Replies: 23
Views: 167

Re: Polar/ Nonpolar

One general rule that I’ve learned is that if a molecule has lone pairs on the central atom, it’s polar!
by Hailey Qasawadish 2J
Sun Nov 22, 2020 10:36 am
Forum: Ionic & Covalent Bonds
Topic: How to determine which molecule is more ionic?
Replies: 11
Views: 116

Re: How to determine which molecule is more ionic?

Usually, to find how “ionic” a bond is, you would look at the electronegativity values to find the biggest difference in electronegativity. If you don’t have these values, you would use the periodic trends to find the biggest difference. A general rule is that when they’re farther apart on the perio...
by Hailey Qasawadish 2J
Sun Nov 22, 2020 10:28 am
Forum: Lewis Structures
Topic: Textbook 2B11 part C
Replies: 4
Views: 19

Re: Textbook 2B11 part C

For molecules that are presented how it is in part C that have many different parts, I like to do it in order to make sure that the correct things are bonded to each other. I believe the NH2 has to go on an end because it is in parentheses, but I could be mistaken. @Hailey, as a general rule, do mo...
by Hailey Qasawadish 2J
Sun Nov 22, 2020 10:25 am
Forum: Formal Charge and Oxidation Numbers
Topic: Best Formal Charge Equations
Replies: 24
Views: 133

Re: Best Formal Charge Equations

The easiest way for me to find formal charge is to count! I start with the number of valence electrons the atom has, then I start in the middle at the atom and start counting down by one for each “thing” around the atom. For example, if nitrogen was surrounded by 3 bonds and 1 lone pair, you would s...
by Hailey Qasawadish 2J
Sun Nov 15, 2020 8:50 pm
Forum: Lewis Structures
Topic: Textbook 2B11 part C
Replies: 4
Views: 19

Re: Textbook 2B11 part C

For molecules that are presented how it is in part C that have many different parts, I like to do it in order to make sure that the correct things are bonded to each other. I believe the NH2 has to go on an end because it is in parentheses, but I could be mistaken.
by Hailey Qasawadish 2J
Sun Nov 15, 2020 8:48 pm
Forum: Resonance Structures
Topic: resonance structures
Replies: 10
Views: 45

Re: resonance structures

The resonance structure that contributes most is the one with the formal charges closest to 0. The sum of the formal charges should give you the overall charge of the structure.
by Hailey Qasawadish 2J
Sat Nov 14, 2020 5:38 pm
Forum: Dipole Moments
Topic: Boiling/Melting Points
Replies: 15
Views: 114

Re: Boiling/Melting Points

The biggest factor in determining boiling/melting points is the strength of the intermolecular forces. The stronger the intermolecular force, the higher the boiling/melting point because it takes more energy to break the bonds if they are stronger.
by Hailey Qasawadish 2J
Fri Nov 13, 2020 10:06 am
Forum: Quantum Numbers and The H-Atom
Topic: angular momentum equation
Replies: 2
Views: 34

Re: angular momentum equation

I think if you know the concept behind the equation, it would be far more beneficial than knowing how to use the equation for the midterm. I don't think we will be responsible for solving anything with this equation.
by Hailey Qasawadish 2J
Fri Nov 13, 2020 10:03 am
Forum: Lewis Structures
Topic: Formal Charge
Replies: 3
Views: 18

Re: Formal Charge

I think it's really important to include the brackets just to ensure that you are acknowledging there is an overall charge on the molecule as opposed to just a formal charge on a specific part.
by Hailey Qasawadish 2J
Thu Nov 12, 2020 5:20 pm
Forum: Octet Exceptions
Topic: octet rule exceptions
Replies: 6
Views: 44

Re: octet rule exceptions

Hydrogen is an exception to the octet rule, as it only needs 2 electrons to be satisfied. Atoms in the 3rd row of the periodic table and below can sometimes take on extra electrons and therefore exceed the octet rule. I read this in the textbook, but wasn't sure if it mean only p-block elements bel...
by Hailey Qasawadish 2J
Thu Nov 12, 2020 5:14 pm
Forum: Lewis Structures
Topic: Sapling hw question
Replies: 2
Views: 29

Re: Sapling hw question

You would have to memorize the formulas for phosphate vs phosphite and nitrate vs nitrite. These are common polyatomic ions that would probably be helpful to memorize! Though, as a general rule, the ions that end with "ite" usually have one less oxygen than the ions that end with "ate...
by Hailey Qasawadish 2J
Thu Nov 12, 2020 5:08 pm
Forum: Bond Lengths & Energies
Topic: Increasing strengths of dispersion forces
Replies: 2
Views: 12

Re: Increasing strengths of dispersion forces

Hi! Yes, you are correct that it has to do with the increasing number of electrons. Due to the higher number of electrons, there is higher polarizability, therefore meaning that the electrons are more easily distorted due to their larger radius (which is dependent on their larger number of electrons...
by Hailey Qasawadish 2J
Sun Nov 08, 2020 2:59 pm
Forum: Quantum Numbers and The H-Atom
Topic: wavelength
Replies: 13
Views: 97

Re: wavelength

No, wavelength will never be negative. Though, the answer can be a very small number in which it would no longer be detectable. But, it will never be negative. Hope this helps.
by Hailey Qasawadish 2J
Sun Nov 08, 2020 2:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Taking Bio and Chem simultaneously
Replies: 26
Views: 114

Re: Taking Bio and Chem simultaneously

I was actually wondering the same thing! I am not sure if it will be too much considering we will be taking another 1 or 2 classes as well.
by Hailey Qasawadish 2J
Sun Nov 08, 2020 2:54 pm
Forum: Electronegativity
Topic: Electronegativity trend
Replies: 18
Views: 92

Re: Electronegativity trend

Electronegativity gets bigger as you move from left to right on the periodic table. It decreases as you go down the periodic table. Hope this helps
by Hailey Qasawadish 2J
Sun Nov 08, 2020 2:47 pm
Forum: Dipole Moments
Topic: Sapling #19
Replies: 3
Views: 16

Re: Sapling #19

Hi! From my understanding, hydrogen bonding is a specific kind of dipole-dipole. Hydrogen bonding only occurs between a hydrogen and either a nitrogen, oxygen, or fluorine. In saying that this is a dipole-dipole, I am assuming this includes hydrogen bonding as hydrogen bonding is a type of dipole-di...
by Hailey Qasawadish 2J
Sun Nov 08, 2020 2:43 pm
Forum: Resonance Structures
Topic: Delocalized Electrons
Replies: 3
Views: 23

Re: Delocalized Electrons

A delocalized electron is basically one that isn't associated to the single atom or the covalent bond. These electrons are basically free to move around rather than being limited to their structure. Hopefully this helps!
by Hailey Qasawadish 2J
Sun Nov 08, 2020 2:37 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge and Lewis Structures
Replies: 10
Views: 74

Re: Formal Charge and Lewis Structures

Finding formal charge is one of the main ways to know if your structure is correct. From what I understand, it is always necessary to check for formal charge because the structure technically isn't correct until formal charge is closest to 0, or the charge is closest to the charge of the molecule. T...
by Hailey Qasawadish 2J
Sun Nov 01, 2020 11:11 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Sapling HW Spectral Lines/Energy Levels
Replies: 4
Views: 44

Re: Sapling HW Spectral Lines/Energy Levels

You basically would have to find the energy difference twice. Once from n=1 to n=7, and then again from n=6 to n=7. I used Rydberg's equation, found the frequency, then used E=hv to find the energy. I did this for each jump. The values you get for your energy are the endpoints for your range. Hope t...
by Hailey Qasawadish 2J
Sun Nov 01, 2020 1:56 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: General Heisenberg Question
Replies: 7
Views: 90

Re: General Heisenberg Question

In regards to uncertainty in position, do we need to multiply the position by 2? On sapling, I did not need to change delta x but I did have to multiply delta x by 2 in some step-up sessions. How do we know when to do this? Hi! I believe it ultimately depends on what the question is asking. You hav...
by Hailey Qasawadish 2J
Sun Nov 01, 2020 1:53 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital reference sheet
Replies: 4
Views: 25

Re: Orbital reference sheet

I think we are expected to memorize the shapes, orbitals, patterns, etc. for the exam. There are a lot of helpful visuals online that put these into organized charts that make it easier to memorize!
by Hailey Qasawadish 2J
Sun Nov 01, 2020 1:51 pm
Forum: Trends in The Periodic Table
Topic: Focus Exercise 1.13
Replies: 2
Views: 21

Re: Focus Exercise 1.13

Hi! Oxygen's ionization energy is lower because of there is a greater electron repulsion in the 2p sub level for oxygen than there is for nitrogen. Thus, it is easier to remove an electron from oxygen than it is for nitrogen making the ionization energy for O less than that of N. This also has to do...
by Hailey Qasawadish 2J
Sun Nov 01, 2020 11:22 am
Forum: Lewis Structures
Topic: Octet Rule
Replies: 12
Views: 74

Re: Octet Rule

Dr. Lavelle has only mentioned the first four elements not following the octet rule. These are H, He, Li, and Be. This is due to the orbital that they are in.
by Hailey Qasawadish 2J
Sun Nov 01, 2020 11:04 am
Forum: SI Units, Unit Conversions
Topic: eV to Joules (Defining these Units) Question
Replies: 12
Views: 99

Re: eV to Joules (Defining these Units) Question

An eV is an electron volt. There is an easy conversion between eV and Joules which is that 1 eV is equal to 1.602 x 10^-19 Joules. (So you would just have to multiply eV's by that conversion factor). This is listed on the equation sheet provided by Dr. Lavelle!
by Hailey Qasawadish 2J
Sun Nov 01, 2020 10:55 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Affinity
Replies: 4
Views: 27

Re: Electron Affinity

A high electron affinity corresponds to a higher release of energy. In contrast, low electron affinity means that it releases a small amount of energy and absorbs energy to do so. You must take into account how stable the element is to understand if they want to lose or gain an electron to become mo...
by Hailey Qasawadish 2J
Sun Oct 25, 2020 8:03 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Diffraction
Replies: 4
Views: 30

Re: Diffraction

With regards to diffraction, how can we tell when a system is constructive vs destructive? Do these properties mean something in particular? Is there certain characteristics of atoms that make the waves have one pattern over the other? Hi! The terms constructive and destructive refer to how the wav...
by Hailey Qasawadish 2J
Fri Oct 23, 2020 2:19 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 1B.21 Clarification
Replies: 3
Views: 50

Re: 1B.21 Clarification

Hi! I started by converting the 5.15 ounces to grams, then to kilograms. (.146 kg) Then, I used dimensional analysis to convert the 92 miles per hour to meters per second. (41 m/s) Then, I used the equation lambda = h/(mass x velocity) to get the answer in meters. (1.1 x 10^-34 meters) Hope this hel...
by Hailey Qasawadish 2J
Fri Oct 23, 2020 10:23 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Textbook Problem E.25
Replies: 3
Views: 49

Re: Textbook Problem E.25

Hi! To answer your first question, formula units are simply just the "units" for an iconic company. Similarly, the formula weight would be the molar mass of the ionic compound. To solve for #25a) you would multiply the moles of KNO3 by Avogadro's number to get how many formula units are in...
by Hailey Qasawadish 2J
Fri Oct 23, 2020 10:15 am
Forum: SI Units, Unit Conversions
Topic: SI Conversions
Replies: 11
Views: 82

Re: SI Conversions

There are unit conversions on the equation sheet, so be familiar with them, and I would also just make sure that you know how to apply the conversion factors! Although, I do think memorizing these more simple ones would be very helpful.
by Hailey Qasawadish 2J
Fri Oct 23, 2020 9:50 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Finding the wavelength between two levels
Replies: 3
Views: 46

Re: Finding the wavelength between two levels

Hi, You would first calculate \nu by converting the given wavelength 102.6 nm into meters and using the equation \nu = \frac{c}{\lambda } derived from c=\lambda \nu You should note that the ultraviolet spectrum corresponds to the Lyman series, where all electrons start at energy level n=1. You can ...
by Hailey Qasawadish 2J
Fri Oct 23, 2020 9:40 am
Forum: Quantum Numbers and The H-Atom
Topic: Rydberg Constant
Replies: 13
Views: 97

Re: Rydberg Constant

These constants are technically the same, they are just in different units. The 3.29 x 10^15 is in Hz. This would be used if you're using frequency in the problem. The other constant is in meters, and it would be used when using wavelength in the problem. Hope this helps!
by Hailey Qasawadish 2J
Mon Oct 19, 2020 7:41 pm
Forum: Properties of Electrons
Topic: Textbook 1A #3
Replies: 2
Views: 40

Re: Textbook 1A #3

Hi! You are correct that the wavelength would increase due to the decreased frequency as wavelength and frequency are inversely proportional based on the equation c=λv. Though, this is not an answer choice, so you must look for something else that is true. C is true because the electrical field is e...
by Hailey Qasawadish 2J
Fri Oct 16, 2020 10:57 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Detecting Wavelengths in Visible Region
Replies: 3
Views: 67

Re: Detecting Wavelengths in Visible Region

Hi! If I'm not mistaken, the ground state doesn't always allude to n=1, but rather it refers to the energy level that it normally occupies. It is basically the state at which the electron is at its lowest energy level. When talking about the Balmer series, the electrons normally occupy n=2 at its lo...
by Hailey Qasawadish 2J
Fri Oct 16, 2020 12:24 am
Forum: General Science Questions
Topic: Polyatomic Ions
Replies: 6
Views: 69

Re: Polyatomic Ions

Hi! I am assuming since nomenclature is a part of most of the problems in the book, we are expected to know it. Although, I don't think Dr. Lavelle has specifically addressed it yet. I do think it's important to know the polyatomic ions though because they are a strong foundation for most problems!
by Hailey Qasawadish 2J
Wed Oct 14, 2020 7:02 pm
Forum: Photoelectric Effect
Topic: Exercise 1B.3
Replies: 2
Views: 45

Re: Exercise 1B.3

The photoelectric effect supports the idea that electromagnetic radiation has the properties of particles because it behaves similarly to an elastic collision. This basically means that between two particles, there is a photon of light and the electron of the metal that will be ejected if there is e...
by Hailey Qasawadish 2J
Wed Oct 14, 2020 4:03 pm
Forum: Properties of Light
Topic: Rearranging Equations
Replies: 4
Views: 48

Re: Rearranging Equations

You always want to ask yourself what you are looking for in a certain problem. With this, you can use "cross multiplication" and variable isolation to make your equation fit what you're trying to solve for. For example, if you are solving for frequency with the equation E=hv, and you are g...
by Hailey Qasawadish 2J
Wed Oct 14, 2020 3:58 pm
Forum: SI Units, Unit Conversions
Topic: Help Understanding SI Units?
Replies: 7
Views: 131

Re: Help Understanding SI Units?

Hello, you would want to use conversation factors if the units in the question don't match the units that the question is asking for in terms of the answer. Essentially, you want to make sure that you are doing all of your calculations in the same unit to ensure you get the right answer. Each unit c...
by Hailey Qasawadish 2J
Wed Oct 14, 2020 3:44 pm
Forum: Properties of Light
Topic: Textbook question 1A.3
Replies: 3
Views: 26

Re: Textbook question 1A.3

Hi! Electromagnetic radiation travels at the speed of light (which is the constant 'c' that we have been using in our calculations). Speed of light is equivalent to 3.00 x 10^8 m/s. It's important to keep in mind that frequency doesn't affect this value. Hope this helps.
by Hailey Qasawadish 2J
Wed Oct 14, 2020 3:33 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E 15
Replies: 3
Views: 90

Re: E 15

Hi! The goal of this problem is to find what the element "m" is. The problems tells us the molar mass of the metal hydroxide which is 74.10 g/mol. With this, we know that the molar mass of some element (we will call this x) + the molar mass of hydroxide (with a subscript of 2) = 74.10 g/mo...
by Hailey Qasawadish 2J
Tue Oct 06, 2020 11:01 pm
Forum: Limiting Reactant Calculations
Topic: Sapling #10 Walkthrough
Replies: 6
Views: 69

Re: Sapling #10 Walkthrough

How do you find the molar mass of 2‑butanone? You find the molar mass of 2-butanone with the chemical formula. You can find out from the picture that there are 4 carbons, 8 hydrogens, and 1 oxygen by looking at the structure. (I wasn't sure at first how to count the carbons and hydrogens, so I look...
by Hailey Qasawadish 2J
Tue Oct 06, 2020 10:58 pm
Forum: Limiting Reactant Calculations
Topic: Sapling #10 Walkthrough
Replies: 6
Views: 69

Re: Sapling #10 Walkthrough

lwong Dis1L wrote:Also, what does the "d" below each of the reactants and products mean?

The D below each of the reactants and products represents density in grams/mL. This allows you to have a conversion factor in order to get to moles. Hope this helps. :)
by Hailey Qasawadish 2J
Tue Oct 06, 2020 10:09 pm
Forum: Molarity, Solutions, Dilutions
Topic: mmol/mL vs. mol/L
Replies: 6
Views: 70

Re: mmol/mL vs. mol/L

From my understanding, M (molarity) is always represented by moles per liter. But ultimately, the two are the same because the 10^-3 would cancel each other out. I always like to convert everything to moles and liters while solving, and if the problem is asking for an answer in mL, I would simply co...
by Hailey Qasawadish 2J
Tue Oct 06, 2020 9:17 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Mass of A Product Procued? (Q#22 Post Assessment LR)
Replies: 5
Views: 49

Re: Mass of A Product Procued? (Q#22 Post Assessment LR)

Hi! Saying that AgCl was completely precipitated does not mean that this is the limiting reactant. Rather, AgCl precipitating out means it is the product that falls out of the solution as a solid. To solve this problem, I started by dividing the grams of each compound by their molar mass in order to...
by Hailey Qasawadish 2J
Tue Oct 06, 2020 7:37 pm
Forum: SI Units, Unit Conversions
Topic: SIGNIFICANT FIGURES IN UNIT CONVERSIONS
Replies: 4
Views: 60

Re: SIGNIFICANT FIGURES IN UNIT CONVERSIONS

Hi! You always want to use the least number of significant figures in the question for your final answer. So if the question is asking for you to convert 4.15 liters to mL, you would want to keep 3 sig figs in your answer. (Hopefully this answers your question). When doing problems involving more ma...
by Hailey Qasawadish 2J
Mon Oct 05, 2020 12:58 pm
Forum: Balancing Chemical Reactions
Topic: Stoichemetric Coeffiecients
Replies: 12
Views: 141

Re: Stoichemetric Coeffiecients

Hi! You would always want to make your stoichiometric coefficients whole numbers or rather integers. In the case where a fraction would satisfy your chemical equal (i.e. 13/2), you would want to multiply everything in your equation by 2 to make the 13/2, 13 instead. I am assuming you would lose poin...
by Hailey Qasawadish 2J
Mon Oct 05, 2020 12:55 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Fundamentals Section M Exercise M.11
Replies: 4
Views: 42

Re: Limiting Reactant Fundamentals Section M Exercise M.11

Hi! The P4O6 is not a part of the equation. It is a part of the sentence before it. The equation begins after the colon. Hope this helps. :)

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