Search found 61 matches

by Sean Cheah 1E
Thu Jan 16, 2020 10:06 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Module 4 Q15
Replies: 2
Views: 18

Re: Module 4 Q15

To be completely honest I have no idea what's going on here either. I was under the assumption that Le Chatelier's Principle, like the equilibrium constant, does not take pure solids and liquids into account. Any further insight would be greatly appreciated! Edit: So I did some digging through sever...
by Sean Cheah 1E
Thu Jan 16, 2020 9:59 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic/Exothermic Rxns and Delta H
Replies: 3
Views: 21

Re: Endothermic/Exothermic Rxns and Delta H

The net chemical equation for photosynthesis is deceptively simple and excludes many of the complex intermediate steps that must take place when converting the reactants to products. For this class, those details are not important. Just know that when you sum all the energy expended to break bonds a...
by Sean Cheah 1E
Thu Jan 16, 2020 9:44 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Factors
Replies: 7
Views: 24

Re: Factors

The reaction quotient depends on the concentrations/pressures of the reactants and products. For reactions not at equilibrium, these values are constantly changing and thus Q is nonconstant. Even for reactions at equilibrium, changes in the concentrations/pressures (adding/removing more reactants/pr...
by Sean Cheah 1E
Thu Jan 16, 2020 9:40 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Today's lecture
Replies: 5
Views: 37

Re: Today's lecture

The Henderson-Hasselbalch equation states that . Use an ICE table to determine the concentrations of the conjugate acid-base pair.
by Sean Cheah 1E
Thu Jan 16, 2020 9:37 am
Forum: Ideal Gases
Topic: R constant
Replies: 6
Views: 22

Re: R constant

As previous posters have already noted, pay careful attention to the units of the given values in each problem when determining which R constant to use. For example, when converting from Keq to delta G, the correct R value would be about 8.314 J*K^{-1}*mol^{-1} , which makes sense seeing as your fin...
by Sean Cheah 1E
Thu Jan 09, 2020 4:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc and Kp
Replies: 2
Views: 11

Re: Kc and Kp

, where is the sum of the coefficients of the gaseous products minus the sum of the coefficients of the gaseous reactants (the change in the number of moles of gas), , and T is temperature in Kelvins.
by Sean Cheah 1E
Thu Jan 09, 2020 4:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook 5H.1 Part 1
Replies: 4
Views: 20

Re: Textbook 5H.1 Part 1

I assume you're referring to part b and not part a as the answer to part a should be 1/41. First note that the given information tells you K = \frac{[N_{2}][H_{2}]^{3}}{[NH_{3}]^{2}} = 41 . Then note that the K value for part b is K = \frac{[N_{2}]^{\frac{1}{2}}[H_{2}]^{\frac{3}{2}}}{[NH_{3}]} = \sq...
by Sean Cheah 1E
Thu Jan 09, 2020 4:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constants with Ionic Compounds
Replies: 2
Views: 16

Re: Equilibrium Constants with Ionic Compounds

A net-ionic equation is one where the species (ions, solvents, etc.) that appear in both the reactants and the products are omitted, leaving only the ions that actually change in some way during the course of the reaction. An net-ionic equation for the dissociation of a solid salt in water would loo...
by Sean Cheah 1E
Thu Jan 09, 2020 4:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp v. Kc
Replies: 5
Views: 16

Re: Kp v. Kc

Kp is calculated using partial pressures and can therefore only be used for reactions that exclusively involve gaseous substances. Kc is calculated using molar concentrations and can be used for all reactions. In those calculations, the concentration of any given gas would simply be the number of mo...
by Sean Cheah 1E
Thu Jan 09, 2020 3:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units when Calculating Kp
Replies: 1
Views: 15

Units when Calculating Kp

Is the value of Kp supposed to change depending on the units used to measure pressure? For part c of 5G.5, the squared term in the numerator of the expression for Kp means that multiplying each pressure measurement by a constant (as one would do when converting between units) would result in a compl...
by Sean Cheah 1E
Thu Dec 05, 2019 11:56 am
Forum: Bronsted Acids & Bases
Topic: Relative strength of base?
Replies: 3
Views: 34

Re: Relative strength of base?

Yes you would look at the same characteristics to determine the strength of a base. Essentially a stronger base, wants to accept a proton easier, and will give off more hydroxide ion. So how would that work though? Cause like for acid, you look at the strength between H and A (the bigger the A, the...
by Sean Cheah 1E
Thu Dec 05, 2019 11:41 am
Forum: Conjugate Acids & Bases
Topic: conjugate base and pH
Replies: 4
Views: 38

Re: conjugate base and pH

The seesaw relationship between the relative strengths of a conjugate acid/base pair states that the conjugate base of a strong acid will be a very weak base and the conjugate acid of a strong base will be a very weak acid. In these cases, the conjugates are so weak that they have basically no effec...
by Sean Cheah 1E
Thu Dec 05, 2019 9:25 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: oxoacid strength - conceptual
Replies: 1
Views: 27

Re: oxoacid strength - conceptual

One of the factors that affect the strength of an acid is the net electron-withdrawing force acting on the H+ that the acid can donate. In the case of oxoacids, increasing the number of oxygens increases this electron-withdrawing force and further polarizes the compound by shifting the electron dens...
by Sean Cheah 1E
Thu Dec 05, 2019 9:17 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: J.17
Replies: 4
Views: 30

Re: J.17

Unfortunately, memorizing a table of common ions may be your best bet here. As far as I know, there is no easy way to determine the charge of an ion given its molecular formula alone.
by Sean Cheah 1E
Thu Dec 05, 2019 9:15 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Are polar/partially charged molecules always acidic?
Replies: 1
Views: 16

Re: Are polar/partially charged molecules always acidic?

I don't actually know the answer to your question but it did remind me of the fact that all amino acids with acidic side chains are negatively charged when deprotonated and all amino acids with basic side chains are positively charged when protonated. Whether or not an acid/base is protonated depend...
by Sean Cheah 1E
Mon Nov 25, 2019 12:45 pm
Forum: Naming
Topic: 9C #9c/d
Replies: 3
Views: 20

Re: 9C #9c/d

En is the abbreviation for ethylenediamine (C2H4(NH2)2) and edta is the abbreviation for ethylenediaminetetraacetic acid (C10H16N2O8).
by Sean Cheah 1E
Mon Nov 25, 2019 12:38 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelateing Ligands
Replies: 3
Views: 25

Re: Chelateing Ligands

Chelating ligands are polydentate ligands that are able to form a ring-like structure of atoms that includes the central metal cation. As an example, each ethylenediamine (molecular formula: C2H4(NH2)2) ligand in the compound pictured below binds the central Cobalt cation to form two such rings. htt...
by Sean Cheah 1E
Mon Nov 25, 2019 12:22 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: How to tell?
Replies: 11
Views: 261

Re: How to tell?

Sometimes it can be difficult to tell whether a given molecule is an acid or a base from its molecular formula alone. For example, NH3 (ammonia) is a weak base despite having several H atoms.
by Sean Cheah 1E
Mon Nov 25, 2019 12:18 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Ligands
Replies: 5
Views: 27

Re: Ligands

Alison Trinh 1A wrote:Can someone explain what exactly a ligand is?

In this context, a ligand refers to an electron-pair donor that forms one or more coordinate covalent bonds with a central metal ion.
by Sean Cheah 1E
Mon Nov 25, 2019 12:17 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strong acids vs weak acids
Replies: 8
Views: 36

Re: Strong acids vs weak acids

Neutralization reactions involving weak acids and bases are a lot more complicated than those that only deal with strong acids and bases. This is because the incomplete ionization of the weak acids and bases results in an equilibrium that one would then need to create a so-called ICE table to solve ...
by Sean Cheah 1E
Fri Nov 22, 2019 8:18 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Definition of a Ligand
Replies: 4
Views: 21

Re: Definition of a Ligand

In this context, a ligand is a Lewis base (electron pair donor) that can form coordinate covalent bonds with transition metal cations. To make things confusing, ligands take on an entirely different definition in the context of biochemistry (cell signaling, enzymatic reactions, etc.).
by Sean Cheah 1E
Fri Nov 22, 2019 8:15 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Absorption of O2
Replies: 1
Views: 23

Re: Absorption of O2

We haven't yet covered equilibrium yet so you likely don't need to know the specifics, but logically speaking it should make sense that the heme group has a higher chance of binding oxygen when the oxygen is at a higher concentration (which is essentially what a higher partial pressure means). Conve...
by Sean Cheah 1E
Fri Nov 22, 2019 8:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Acids
Replies: 6
Views: 21

Re: Acids

A strong acid is one that fully dissociates in water while a weak acid is one that only partially dissociates (equilibrium dictated by something called a Ka value).
by Sean Cheah 1E
Fri Nov 22, 2019 8:10 pm
Forum: Hybridization
Topic: lone pairs in hybridization
Replies: 8
Views: 35

Re: lone pairs in hybridization

When determining the hybridization scheme of a certain atom, all electron domains should be counted, whether they be bonding or lone pairs. Bonding electrons will essentially singly occupy their respective hybridized orbitals (allowing sigma bonds to form via interactions with other orbitals only co...
by Sean Cheah 1E
Fri Nov 22, 2019 8:07 pm
Forum: Hybridization
Topic: hybridization
Replies: 11
Views: 57

Re: hybridization

^^ What is a step by step method? I don't think there is any kind of step-by-step method. All you need to determine the hybridization scheme of a certain central atom is the number of regions of electron density around that atom (which one can very easily determine using the Lewis dot structure). 2...
by Sean Cheah 1E
Thu Nov 14, 2019 9:27 am
Forum: Lewis Structures
Topic: 2.7
Replies: 2
Views: 37

Re: 2.7

Honestly, I think you just have to approach the problem like any other Lewis structure question and work it out by hand using the number of total valence electrons. Wikipedia says that this ion (the pentazenium cation) has six possible resonance structures given by: [N≡(N+)−(N−)−(N+)≡N]+ ↔ [(N−)=(N+...
by Sean Cheah 1E
Thu Nov 14, 2019 9:22 am
Forum: Lewis Structures
Topic: Curiosity [ENDORSED]
Replies: 6
Views: 776

Re: Curiosity [ENDORSED]

Not 100% sure if this is correct, but I drew it with the Se in the middle and the O's surrounding it. For 2 of the O's I drew double bonds and 2 lone pairs, and for the other 2 O's I attached H's and 2 lone pairs. Yeah, a quick Google search reveals that this is the correct Lewis structure. Now for...
by Sean Cheah 1E
Thu Nov 14, 2019 9:18 am
Forum: Ionic & Covalent Bonds
Topic: Electronegativity
Replies: 7
Views: 41

Re: Electronegativity

Electronegativity is actually one of the more consistent periodic trends and generally increases across a period and decreases down a group. While a similar trend characterizes the ionization energies, do note (as mentioned above) that there is no decrease in electronegativity from N to O and from B...
by Sean Cheah 1E
Thu Nov 14, 2019 9:08 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Difference between molecular shape
Replies: 3
Views: 36

Re: Difference between molecular shape

I found this simple table online that might help you visualize and remember all the various molecular geometries.
Image
by Sean Cheah 1E
Thu Nov 14, 2019 9:03 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Deciding Between Trigonal Planar vs Trigonal Pyramidal
Replies: 4
Views: 32

Re: Deciding Between Trigonal Planar vs Trigonal Pyramidal

You can count the number of regions of electron density and the number of lone pairs around a central to quickly determine its corresponding molecular geometry. Trigonal planar geometries occur when there are 3 regions of electron density of which none are lone pairs. Trigonal pyramidal geometries o...
by Sean Cheah 1E
Fri Nov 08, 2019 12:13 pm
Forum: Dipole Moments
Topic: Drawing Unpaired Electrons
Replies: 7
Views: 48

Re: Drawing Unpaired Electrons

Always make sure that the total number of electrons in your final Lewis dot structure (whether they be in lone pairs, bonds, or single dots in the case of the unpaired and nonbonding electrons of radicals) is equal to the sum of the valence electrons of all the atoms in the structure.
by Sean Cheah 1E
Fri Nov 08, 2019 12:06 pm
Forum: Electronegativity
Topic: Determining Electronegativity
Replies: 4
Views: 45

Re: Determining Electronegativity

Remember that electronegativity generally increases going across a period (left to right) and decreases going down a group. You can use this trend to figure out the relative magnitudes of the electronegativity differences.
by Sean Cheah 1E
Thu Nov 07, 2019 12:15 pm
Forum: Ionic & Covalent Bonds
Topic: 2D.9
Replies: 3
Views: 30

Re: 2D.9

The way I like to remember this is that ions with larger charge/size ratios have higher polarizing power. Thus, as both smallest by ionic radii and one of only two in your list carrying a relatively large 2+ charge, Be2+ has the largest charge/size ratio and therefore also has the highest polarizing...
by Sean Cheah 1E
Thu Nov 07, 2019 12:08 pm
Forum: Ionic & Covalent Bonds
Topic: coulomb potential energy and Madelung constant, as well as lattice energy
Replies: 4
Views: 39

Re: coulomb potential energy and Madelung constant, as well as lattice energy

Lattice energy represents the change in energy that occurs when separated gaseous ions are packed together to form the ionic solid, which is always negative due to the process being exothermic. This kinda gets into the realm of physics but essentially the negative derivative of the electrostatic for...
by Sean Cheah 1E
Thu Nov 07, 2019 11:23 am
Forum: Ionic & Covalent Bonds
Topic: Ionic vs Covalent
Replies: 14
Views: 104

Re: Ionic vs Covalent

Additionally, an electronegativity difference less than 0.5 generally represents a nonpolar covalent bond while an electronegativity difference between 0.5 and around 1.5 represents a polar covalent bond.
by Sean Cheah 1E
Mon Oct 28, 2019 1:32 pm
Forum: Lewis Structures
Topic: lewis structures
Replies: 5
Views: 41

Re: lewis structures

While it is true that the atoms with the lowest ionization energies generally go in the center, this is not always the case. For example, I challenge anyone who does not already know the structure of HNO2 (nitrous acid) to draw its Lewis structure from scratch and compare that with its real structur...
by Sean Cheah 1E
Mon Oct 28, 2019 1:18 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge equation?
Replies: 5
Views: 42

Re: Formal Charge equation?

Honestly, while memorizing the equation is fine and good, I like to tally up the number of electrons to subtract by simply counting each bond as one electron as each lone pair as two electrons. For example, if I saw a double bond, a single bond, and two lone pairs around a hypothetical atom, I could...
by Sean Cheah 1E
Mon Oct 28, 2019 1:02 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Finding Most Stable Structure
Replies: 9
Views: 55

Re: Finding Most Stable Structure

How do you know which atom can hold more of the negative charge? To maximize the stability of your structure, any remaining negative formal charge should be preferably assigned to the more electronegative elements first. I'm sure Lavelle will not expect us to memorize the electronegativities for al...
by Sean Cheah 1E
Mon Oct 28, 2019 12:55 pm
Forum: Formal Charge and Oxidation Numbers
Topic: In Class Example, Sulfate
Replies: 3
Views: 42

Re: In Class Example, Sulfate

After getting the formal charge on each atom as close to zero as possible, place the remaining negative formal charge(s), if present, on the more electronegative atom(s) and the positive formal charge(s), if present on the less electronegative atom(s) to get the most stable structure. The reason tha...
by Sean Cheah 1E
Mon Oct 28, 2019 12:30 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Finding Most Stable Structure
Replies: 9
Views: 55

Re: Finding Most Stable Structure

In cases where it is impossible to entirely eliminate the formal charge on each atom, the most stable structure will have the negative formal charges on the more electronegative atoms and the positive formal charges on the less electronegative atoms.
by Sean Cheah 1E
Wed Oct 23, 2019 4:09 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Spin
Replies: 8
Views: 55

Re: Electron Spin

Does Hund's rule apply to the Pauli Exclusion Principle? This is a bit of a strange question to ask. Hund's Rule describes the order in which electrons fill a subshell and is composed of two main statements: every orbital in a subshell must be singly occupied before any are doubly occupied, and all...
by Sean Cheah 1E
Mon Oct 21, 2019 10:39 am
Forum: Quantum Numbers and The H-Atom
Topic: Z
Replies: 5
Views: 48

Re: Quantum Number Z

Hi, To my understanding, Z is not one of the four types of quantum numbers [those are principal quantum number (n), the orbital angular momentum quantum number (l), the magnetic quantum number (ml), and the electron spin quantum number (ms)]. Z, in this context, is involved with the quantum number ...
by Sean Cheah 1E
Mon Oct 21, 2019 10:32 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Difference between the electron shell and orbitals
Replies: 4
Views: 38

Re: Difference between the electron shell and orbitals

All the answers above me are close but just ever so slightly off. While it is true that each shell contains one or more orbitals, it is not entirely correct to say that each angular momentum quantum number l represents an orbital within a given shell with principal quantum number n. This becomes obv...
by Sean Cheah 1E
Mon Oct 21, 2019 10:08 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Wave Function and Uncertainty
Replies: 3
Views: 32

Re: Wave Function and Uncertainty

If my understanding is correct, the squared absolute value (well, technically modulus but I won't get into that) of the wave function describes the probability density of observing an electron in the orbital described by the function, essentially how likely you are to find an electron at any given t...
by Sean Cheah 1E
Mon Oct 21, 2019 9:53 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals and Energy Levels
Replies: 2
Views: 29

Re: Orbitals and Energy Levels

If it helps, you can think of the various quantum numbers for electrons as a hierarchy of sorts. Starting from the bottom going up, the spin quantum number ( m_{s} ) represents the spin of a given electron. The magnetic quantum number ( m_{l} ) represents the specific orbital that contains that elec...
by Sean Cheah 1E
Mon Oct 21, 2019 9:35 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Why is 4s before 3d?
Replies: 9
Views: 77

Re: Why is 4s before 3d?

As mentioned by previous posters, the 4s orbital is filled before the 3d orbitals because it actually has lower energy than the 3d orbitals before they are populated. Note however that this reverses as soon as electrons begin to fill the 3d orbitals, at which point the electrons in the 4s orbital wi...
by Sean Cheah 1E
Wed Oct 16, 2019 12:44 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: What are subshells
Replies: 4
Views: 49

Re: What are subshells

As posted above, the letters s, p, d, and f are refer to subshells, which, as their name implies, are subsets of shells. Each of these subshells contain one or more discrete orbitals that are represented by the various possible orbital angular momentum quantum numbers for a given shell and subshell....
by Sean Cheah 1E
Wed Oct 16, 2019 12:30 pm
Forum: DeBroglie Equation
Topic: Given the energy, calculate the wavelength of y-rays
Replies: 11
Views: 1349

Re: Given the energy, calculate the wavelength of y-rays

also how do you convert the 10^-12 answer into nm As stated above, the answer to your first question is that c in this case simply represents the speed of light, which is a constant that is approximately equal to 3\times 10^{8} m/s. To convert from 10^{-12} m to nm, simply multiply by the conversio...
by Sean Cheah 1E
Wed Oct 16, 2019 12:20 pm
Forum: DeBroglie Equation
Topic: Calculating Wavelength
Replies: 5
Views: 55

Re: Calculating Wavelength

Hi! I haven't done this problem before but I think what it means is that after you calculate the difference of the wavelengths (between protons and neutrons), you need to then calculate how much of the wavelength of neutron does this difference in wavelengths take up. Namely, diff divide by wavelen...
by Sean Cheah 1E
Wed Oct 16, 2019 12:15 pm
Forum: DeBroglie Equation
Topic: Wavelength of Radiation
Replies: 3
Views: 31

Re: Wavelength of Radiation

I almost got tripped up by this question as well. After thinking it over, I believe that it is asking for the wavelength of the light that would eject an electron that with the given final velocity. In this case, you need to use the equation \frac{1}{2}mv^{2}=h\nu -\Phi , where m is the mass of an e...
by Sean Cheah 1E
Wed Oct 16, 2019 12:02 pm
Forum: DeBroglie Equation
Topic: 1B.9 HW Question
Replies: 8
Views: 80

Re: 1B.9 HW Question

Drake Choi_1I wrote:When converting from photons to moles, would it be 6.022 x 10^23 photons to 1 mole?

Yes, that is correct. Whenever you are converting to moles you simply divide the amount of whatever you have by Avogadro's number.
by Sean Cheah 1E
Sat Oct 12, 2019 12:52 pm
Forum: Properties of Electrons
Topic: Electron Energy Levels
Replies: 8
Views: 47

Re: Electron Energy Levels

This contradicts a lot of what's already been posted here, but I always thought that an electron could be excited to any electron level from 1 to a theoretical infinity (e.g. completely removed from the atom) depending on the energy of the photon that it interacts with. I don't think the energy leve...
by Sean Cheah 1E
Sat Oct 12, 2019 12:33 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg equation [ENDORSED]
Replies: 73
Views: 1610

Re: Rydberg equation [ENDORSED]

Can someone please tell me which units cancel out when solving the Rydberg equation? The principal quantum numbers (the n's) have no units. The Rydberg constant has the units m^{-1} . Basically, everything on the right side will work out to some answer with the units m^{-1} . This matches the left ...
by Sean Cheah 1E
Sat Oct 12, 2019 12:29 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg equation [ENDORSED]
Replies: 73
Views: 1610

Re: Rydberg equation [ENDORSED]

are the final units wirtten in Hz or Js? This depends on what the question is asking for. The traditional form of the Rydberg formula, as posted by MAC 1G above, allows you to plug in constants on the left side to get 1 over the wavelength of the photon that will be emitted/absorbed when an electro...
by Sean Cheah 1E
Sat Oct 12, 2019 12:21 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg equation [ENDORSED]
Replies: 73
Views: 1610

Re: Rydberg equation [ENDORSED]

In class, Professor Lavelle wrote the Rydberg equation with a negative sign on the right to show that energy was being lost. Unfortunately when I used the equation that way, my negatives got all messed up and my answer was wrong...Should I just forget that negative? When using the Rydberg formula, ...
by Sean Cheah 1E
Sat Oct 12, 2019 12:00 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Test 1 [ENDORSED]
Replies: 107
Views: 2739

Re: Test 1 [ENDORSED]

curry 1E wrote:Can someone explain what Angstroms are? I was confused on the test on this question.

Angstroms are a unit of length equivalent to 10^(-10) m.
by Sean Cheah 1E
Mon Sep 30, 2019 7:48 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Balancing Equations [ENDORSED]
Replies: 25
Views: 471

Re: Balancing Equations [ENDORSED]

An easy way for me to determine what number to multiple a decimal by to get a whole number is to divide 1 by the decimal. For example: If there are 2.5 mols of C, do 1/0.5 = 2. You should multiply the 2.5 mols by 2 to get a whole number (5). If it's a more difficult value, maybe like 2.125 mols of ...
by Sean Cheah 1E
Mon Sep 30, 2019 7:41 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Aqueous Solution
Replies: 6
Views: 69

Re: Aqueous Solution

It's important to note that the term aqueous solution only tells you that the solvent (the "dissolver") is water and that your solution is stable (i.e. it won't separate out over time). The solute (the dissolved substance) can be ionic or covalent, a solid, a gas, or even another liquid.
by Sean Cheah 1E
Mon Sep 30, 2019 7:34 pm
Forum: Significant Figures
Topic: Question About Significant Figures and Rounding
Replies: 22
Views: 303

Re: Question About Significant Figures and Rounding

Agree with Paul on all counts. I personally only worry about significant digits at the very end of my calculations and the post below can back me up on that.
https://physics.stackexchange.com/questions/63328/do-you-round-off-insignificant-digits-in-the-middle-of-a-calculation
by Sean Cheah 1E
Mon Sep 30, 2019 7:23 pm
Forum: SI Units, Unit Conversions
Topic: Nomenclature
Replies: 4
Views: 124

Re: Nomenclature

For ionic compounds, I'd highly recommend that you take a look at a table of common ions and make a serious effort to memorize both their names and charges (using flashcards or whatever method works best for you). Learning the names (paying special attention to those pesky prefixes and suffixes) let...
by Sean Cheah 1E
Mon Sep 30, 2019 6:59 pm
Forum: SI Units, Unit Conversions
Topic: Memorizing Metric Conversions
Replies: 8
Views: 138

Re: Memorizing Metric Conversions

Seeing as the original request for helpful metric prefix mnemonics has been fulfilled, I want to piggyback off this post to ask if anyone has any tips for memorizing conversion factors from SI to imperial or vice versa (e.g. Fahrenheit to Kelvin, km to mi, etc).

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