## Search found 70 matches

Sun Jan 24, 2021 6:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess Law
Replies: 10
Views: 151

### Re: Hess Law

As far as I know, if you're not multiplying by anything or reversing the reactions, just add the values together. If you reverse a reaction, add the opposite value of the reaction enthalpy. If you multiply by a coefficient, multiply the reaction enthalpy with the same coefficient.
Sun Jan 24, 2021 6:06 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Sapling Week 3 #6
Replies: 5
Views: 16

### Re: Sapling Week 3 #6

Notice that in this reaction, two compounds are combining to form a new one. When you form bonds, you release energy. Hence, it's exothermic.
Tue Jan 19, 2021 2:53 pm
Forum: Bronsted Acids & Bases
Topic: Difference Between Amphoteric and Amphiprotic
Replies: 3
Views: 17

### Difference Between Amphoteric and Amphiprotic

Can someone explain with examples?
Tue Jan 19, 2021 11:04 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Sapling Question 3
Replies: 4
Views: 37

### Sapling Question 3

How do you use the quadratic equation to solve for percent ionization?
Mon Jan 18, 2021 10:27 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH for Strong Acids
Replies: 3
Views: 17

### pH for Strong Acids

Why is the pH for strong acids just the negative log of the molar concentration of the acids?
Sun Jan 17, 2021 12:53 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: How do we know a compound is a weak acid or base?
Replies: 6
Views: 23

### How do we know a compound is a weak acid or base?

For example, many of the problems in 6D basically require an understanding of whether the compound used is acidic or basic. How can we tell this just by looking at the compound
Sun Jan 17, 2021 12:36 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6D7
Replies: 1
Views: 10

### 6D7

Find the initial concentration of the weak acid or base in each of the following aqueous solutions: (a) a solution of HClO with pH 4.60; (b) a solution of hydrazine, NH2NH2, with pH 10.20. Can somebody explain how they set up the problem for these? I know that you compute 10^-pH for the concentratio...
Wed Jan 13, 2021 8:04 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Writing out the chemical equations when calculating ion concentrations?
Replies: 3
Views: 15

### Writing out the chemical equations when calculating ion concentrations?

In example 6a2, when we're calculating the OH- concentration from Ba(OH)2, the chemical equation is only Ba(OH)2 dissociating. In other words, we don't put in H20, it's just Ba(OH)2(s) --> Ba2+(aq) + OH2-(aq). But when I work out the answer for self test 6a3a (which is right underneath), I get the a...
Wed Jan 13, 2021 7:59 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6.A.21
Replies: 4
Views: 30

### 6.A.21

The value of Kw for water at body temperature (37 degrees C) is 2.1 x 10^-14. (a) What is the molar concentration of H3O+ ions at 37 degrees C? (b) What is the molar concentration of OH2- in neutral water at 37 degrees C? Can someone explain how to do this? Also, for part b, does "neutral water...
Wed Jan 13, 2021 12:13 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Textbook Question 6A.3A
Replies: 4
Views: 25

### Re: Textbook Question 6A.3A

I just rechecked the question as well. It does say 6*10^-5 molar concentration for HI. This means that the concentration of H3O+ will be 6*10^-5 molar as HI is a strong acid and completely dissociates. Using the equation for Kw = [H30+][OH-] and knowing that Kw at 25 degrees Celsius is 1*10^-14, we...
Wed Jan 13, 2021 11:21 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Textbook Question 6A.3A
Replies: 4
Views: 25

### Re: Textbook Question 6A.3A

We know that HI is a strong acid and will fully dissociate as an aqueous solution (HI(aq) + H2O -> H3O+(aq) + I-(aq)). Since you know the molar concentration for HI, you can calculate how many moles (and therefore concentration) of H3O+ will be produced. This should be 6.0 x 10 ^-3 M because there'...
Wed Jan 13, 2021 10:40 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Textbook Question 6A.3A
Replies: 4
Views: 25

### Textbook Question 6A.3A

Estimate the concentrations of (a) H3O+ and (b) OH- at 25 degrees C in 6.0 x 10 ^-3 M HI(aq).

Can someone explain how to do this?
Sat Jan 09, 2021 9:01 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to use Ideal Gas Law for Equilibrium Problems
Replies: 1
Views: 17

### When to use Ideal Gas Law for Equilibrium Problems

I remember going to a workshop hosted by Justin in which we did a problem where we used the Ideal gas law to calculate either the pressure or concentration of a reactant. When I was doing Problems from 5I, I thought I could use this same method, but instead, I had to take the moles and simply divide...
Sat Jan 09, 2021 8:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to Use Net Ionic Equations for K constant?
Replies: 1
Views: 13

### When to Use Net Ionic Equations for K constant?

Basically the title. There was a little portion in 5G that said to use the net ionic equations when calculating K for compounds that dissolve completely. However, pretty much all the problems in the book and modules don't do this. When should I be expected to use this method
Fri Jan 08, 2021 10:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Focus 5.I.13
Replies: 1
Views: 23

### Focus 5.I.13

For reference, I'm having trouble with part b: In an experiment, 2.0 mmol Cl2(g) was sealed into a reaction vessel of volume 2.0 L and heated to 1000. K to study its dissociation into Cl atoms. Use the information in Table 5G.2 to calculate the equilibrium composition of the mixture. (b) If 2.0 mmol...
Mon Jan 04, 2021 1:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How do you write the K for an equation with heterogeneous equilibria?
Replies: 10
Views: 58

### How do you write the K for an equation with heterogeneous equilibria?

For example, let's say the reactants are an aqueous solution and a solid and the products are a gas and an aqueous solution?
Mon Jan 04, 2021 1:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How does temperature affect the concentration of products and reactants?
Replies: 2
Views: 46

### How does temperature affect the concentration of products and reactants?

Dr. Lavelle said something along the lines of this in the lecture today. Can someone explain why this is the case?
Wed Dec 16, 2020 2:59 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Difference between pH and pOH
Replies: 12
Views: 66

### Re: Difference between pH and pOH

pH is the concentration of H+ ions while pOH is the concentration of OH- ions. Kb signifies the dissociation constant of a base with increasing the stronger the base is (because strong bases dissociate completely). Alternatively, pKb is the log of the constant. The greater this value, the weaker the...
Wed Dec 16, 2020 2:57 pm
Forum: Lewis Acids & Bases
Topic: Lewis vs Bronsted
Replies: 20
Views: 87

### Re: Lewis vs Bronsted

A Bronsted acid is a hydrogen ion (proton) donor while a Lewis acid is an electron acceptor. A Bronsted base is a hydrogen ion (proton) acceptor while a Lewis base is an electron donor.
Wed Dec 16, 2020 2:53 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Buffer Definition
Replies: 3
Views: 38

### Re: Buffer Definition

A buffer is a solution that resists pH change when an acidic or basic compound is added. It's composed of a conjugate acid and conjugate base that are present in equilibrium, and they neutralize acids and bases in the form of hydronium and hydroxide ions.
Fri Dec 11, 2020 8:54 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Help with Example Question
Replies: 1
Views: 35

### Help with Example Question

A proton is accelerated in a cyclotron to a very high speed that is known to within 3.0 x 10 2 km/s. What is the minimum uncertainty in its position? this is an example question in the 1B section but because the work isn't displayed, I'm not sure where I'm going wrong with it. The answer is .11 pm. ...
Wed Dec 09, 2020 11:17 am
Forum: Limiting Reactant Calculations
Topic: M11 Help
Replies: 1
Views: 26

### M11 Help

A reaction vessel contains 5.77 g of white phosphorus and 5.77 g of oxygen. The first reaction to take place is the formation of phosphorus(III) oxide, P4O6: P4(s) 1 3 O2(g) S P4O6(s). If enough oxygen is present, the oxygen can react further with this oxide to produce phosphorus(V) oxide, P4O10: P4...
Sun Dec 06, 2020 10:21 pm
Forum: Molarity, Solutions, Dilutions
Topic: G19
Replies: 3
Views: 43

### Re: G19

When they say the sample is transferred to a flask or container of X volume, your second volume for your calculation is only X. You don't need to add the original sample volume. So basically, don't add anything to the 125 ml. Hope this helps!
Sun Dec 06, 2020 10:03 pm
Forum: Naming
Topic: Monodentates and Polydentates
Replies: 8
Views: 67

### Re: Monodentates and Polydentates

A good way to remember the differences between these two is interpreting them as # + tooth. For example, monodentates are "one toothed." Therefore, they only bind to one ligand. Similarly, polydentates are "many toothed." They can bind to more than one ligand.
Sun Dec 06, 2020 10:00 pm
Forum: Naming
Topic: -ate
Replies: 17
Views: 83

### Re: -ate

-ate is used at the end of the compound's name when its net charge is negative. Otherwise, or when it's neutrally or positively charged, you don't have any suffix.
Sun Dec 06, 2020 9:57 pm
Forum: Naming
Topic: Coordination Compound vs complex ion
Replies: 4
Views: 70

### Re: Coordination Compound vs complex ion

A coordination compound is a compound with one or multiple metal centers that bind to ligands. Complex ions have metal ions at their centers and are surrounded by other molecules or ions. Coordination compounds differ from complex ions because of their lack of charge. Coordination compounds have no ...
Sun Dec 06, 2020 9:54 pm
Forum: Naming
Topic: "(en)" Sapling
Replies: 19
Views: 111

### Re: "(en)" Sapling

En is the abbreviation for the coordination compound ethylenediamine. It's a bidentate ligand which means that its nitrogens donate their lone pairs when it acts as a donor.
Sun Nov 29, 2020 11:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron vs Molecular Geometry
Replies: 4
Views: 33

### Electron vs Molecular Geometry

What's the difference between electron and molecular geometry? How do you find the former?
Sun Nov 29, 2020 11:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H2O VSEPR
Replies: 27
Views: 147

### Re: H2O VSEPR

There's one central atom (A), two interactions occurring on account of the bonding with two hydrogen atoms (B2), and two lone pairs on the central atom (E2). Upon examining the molecule with the geometry of AB2E2, the descriptor is bent.
Sun Nov 29, 2020 11:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Delocalized vs localized
Replies: 12
Views: 82

### Re: Delocalized vs localized

Localized electrons act like they normally do. For example, lone pairs that are localized remain close to their respective atom. However, delocalized atoms appear in different locations among different forms of a molecule.
Sun Nov 29, 2020 11:34 pm
Forum: Hybridization
Replies: 2
Views: 37

### Re: General Question about Hybridization

In a nutshell, you're taking the atomic orbitals you already have and mixing them to make new orbitals. And much like how mixing different chemical compounds can lead to new properties, creating new orbitals leads to new molecular geometries and bonding characteristics. One easy way to determine the...
Sun Nov 29, 2020 11:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Equatorial vs. Axial
Replies: 4
Views: 39

### Re: Equatorial vs. Axial

Equatorial atoms are those which bond with non ring atoms and form angles that are small compared to the plane of the ring. Axial atoms are those which bond with non-ring atoms and form angles that reach up to 90 degrees. Also, equatorial are an a horizantal axis (think equator) and axial are on a v...
Sun Nov 29, 2020 11:08 pm
Forum: Hybridization
Topic: Single Bonds and Sigma Bonds
Replies: 23
Views: 113

### Re: Single Bonds and Sigma Bonds

In order to count sigma bounds, you do have to count the single bonds. So, in a way, single bonds are sigma bonds. However, it's also important to note that sigma bonds also occur in double and triple bonds.
Sun Nov 22, 2020 9:57 pm
Forum: Lewis Structures
Topic: NO2 Polarity
Replies: 6
Views: 56

### Re: NO2 Polarity

Periodic trends show that moving from left to right on the periodic table increases electronegativity. As a result, oxygen is more electronegative than nitrogen: there will be a disproportionate sharing of electrons among the oxygen atoms in the molecule making nitrogen slightly positive and the oxy...
Sun Nov 22, 2020 9:54 pm
Forum: Trends in The Periodic Table
Topic: Ion Trends
Replies: 18
Views: 96

### Re: Ion Trends

The ion related trends are as follows. When you move from top to bottom of the periodic table, the ionic radius decreases, the ionization energy decreases, and electronegativity decreases. Moving from left to right shows that ionic radius increases, ionization energy increases, and electronegativity...
Sun Nov 22, 2020 9:51 pm
Forum: Trends in The Periodic Table
Topic: Identifying Elements
Replies: 8
Views: 94

### Re: Identifying Elements

Elements within the same group share the number of valence electrons in common which is vital to their characterizing considering its the valence electrons that participate in the reactions. This explains similarities in chemical properties.
Sun Nov 22, 2020 9:49 pm
Forum: Trends in The Periodic Table
Topic: Metallic Character
Replies: 7
Views: 72

### Re: Metallic Character

Metallic character is greatest in the lowest left corner of the periodic table because of the increased shielding that occurs and the minimal effective nuclear charge that results from this. As a result, it's very easy for these elements to lose atoms.
Mon Nov 16, 2020 1:22 pm
Forum: Trends in The Periodic Table
Topic: Inert-Pair Effect
Replies: 1
Views: 40

### Inert-Pair Effect

Can someone explain why this occurs?
Sun Nov 15, 2020 8:58 pm
Forum: Lewis Structures
Topic: Sapling 9
Replies: 8
Views: 75

### Sapling 9

How do you best distinguish which Lewis structures are the best via formal charge and bond length? I'm struggling to pick the right structures. For reference, this is the one about the perchlorate ion.
Sun Nov 15, 2020 7:20 pm
Forum: Resonance Structures
Topic: Sapling Weeks 5 and 6 # 3
Replies: 2
Views: 36

### Sapling Weeks 5 and 6 # 3

Can someone explain how they did the phosphite ion resonance structure? I was able to draw all the other resonance structures but I'm stuck on this one.
Sun Nov 15, 2020 2:10 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: D orbital
Replies: 4
Views: 28

### Re: D orbital

Mikayla Kwok 3L wrote:4s does have a lower energy than 3d when no electrons are in the 3d subshell, but once the 4s and 3d subshells are occupied (which happens after Z=20), 3d has the lower energy.

Sorry is it ok if you explain why? I just want to understand it conceptually. Thanks :))
Sun Nov 15, 2020 12:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: D orbital
Replies: 4
Views: 28

### D orbital

I was watching the first lecture of Week 4 and Dr. Lavelle, at one point, said that the 3d orbital is a higher energy level than the 4s orbital. But then he said multi electron atoms with Z=20 and onward have 4s as the higher energy level orbital. Why is this the case?
Sat Nov 14, 2020 9:42 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: The g subshell
Replies: 1
Views: 15

### The g subshell

Can someone explain this in depth? When would this be present in an atom, if at all?
Sat Nov 14, 2020 9:39 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Textbook 1.D 23 part c
Replies: 2
Views: 33

### Textbook 1.D 23 part c

This part of the question reads How many orbitals can have the following quantum
numbers in an atom: (c) n = 2. Can someone explain how they got the answer to this one?
Sun Nov 08, 2020 10:36 pm
Forum: Trends in The Periodic Table
Topic: Effective nuclear charge
Replies: 5
Views: 46

### Re: Effective nuclear charge

The effective nuclear charge is the net positive charge experienced by an electron in a polyelectronic atom. The periodic trend for determining weakest to strongest e.n.c is as follows: it increases as you move from left to right on the periodic table and decreases as you move from top to bottom. So...
Sun Nov 08, 2020 10:28 pm
Forum: Limiting Reactant Calculations
Topic: Stoichiometric Problem
Replies: 3
Views: 46

### Re: Stoichiometric Problem

You'll probably be given what you're looking for in the form of, say, atoms. You can use the equation N=nNa to calculate for whatever you need to find with N=atoms/molecules/etc of whatever, n= moles of whatever, and Na= Avogrado's constant.
Sun Nov 08, 2020 10:25 pm
Forum: Balancing Chemical Reactions
Topic: Text Book Problems
Replies: 3
Views: 36

### Re: Text Book Problems

Hey! I wouldn't worry about that. We never got a list of any specific compounds or polyatomic ions that we should have down for the course. I don't think we'll be tested on knowing the formulas of random substances we're given on problems.
Sun Nov 08, 2020 10:21 pm
Forum: Significant Figures
Topic: Sig Figs for electron shells
Replies: 4
Views: 73

### Re: Sig Figs for electron shells

I think you have it down right: in general, I use other values in my calculations to determine sig figs. And I remember that one of the sig fig rules on the 14A website said that integers aren't counted for sig figs. So I wouldn't really worry about this issue. Use wavelength/frequency instead.
Sun Nov 08, 2020 10:18 pm
Forum: SI Units, Unit Conversions
Topic: conversion factors
Replies: 8
Views: 62

### Re: conversion factors

Hello. It's important to know constants like Avogrado's and Planck's that are used often in calculations. And by "know," I mean being familiar with their uses considering we get a sheet of constants to use on our tests. In addition, I'd say that familiarity with that chart of SI to metric ...
Sun Nov 01, 2020 8:39 pm
Forum: Significant Figures
Topic: When should I start looking at sig figs?
Replies: 31
Views: 235

### Re: When should I start looking at sig figs?

I think this was mentioned casually in an earlier lecture or module video. But if I were you, I wouldn't do anything with sig figs (as in rounding the numbers) until you have finished all computations. If you're worried about what to write (because sometimes your number has seven numbers after the d...
Sun Nov 01, 2020 8:35 pm
Forum: Significant Figures
Topic: 0's
Replies: 21
Views: 194

### Re: 0's

When it comes to zeroes and decimals, all zeroes after a decimal point are significant. For example: 17.00. Also, when there are zeroes before a decimal point, they can be significant as long as they're "trailing" or the last kind of number in the value. For example: 170.00
Sun Nov 01, 2020 8:33 pm
Forum: Significant Figures
Topic: Sig Figs and Scientific Notation
Replies: 10
Views: 98

### Re: Sig Figs and Scientific Notation

The only numbers that count for sig figs in scientific notations are those of the value being multiplied with the 10^n. In other words: no.
Sun Nov 01, 2020 8:32 pm
Forum: SI Units, Unit Conversions
Topic: unit conversions
Replies: 24
Views: 254

### Re: unit conversions

The most common way I see conversions presented when looking at conversion charts is essentially x•10^y. I think for the sake of leaving things uncomplicated, this would probably be the best way to go. Also, it keeps sig figs consistent.
Sun Nov 01, 2020 8:30 pm
Forum: SI Units, Unit Conversions
Topic: Dimensional Analysis
Replies: 7
Views: 72

### Re: Dimensional Analysis

Dimensional analysis is the process by which you convert one unit to another. For example, it can be something as simple as converting from meters to centimeters, in which you're increasing within a specific unit of length, or converting from degrees Celsius to Kelvin, in which you're converting fro...
Sun Oct 25, 2020 6:25 pm
Forum: Ionic & Covalent Bonds
Topic: hydrogen
Replies: 19
Views: 241

### Re: hydrogen

Hydrogen bonding is when a hydrogen atom bonded to a much more electronegative atom (essentially F, O, or N) forms an attraction to an H atom bonded to another such electronegative atom. The ability for these H atoms to form an attraction to other H atoms relies on polarity resulting from bonding wi...
Sun Oct 25, 2020 6:22 pm
Forum: Balancing Chemical Reactions
Topic: Naming compounds
Replies: 21
Views: 194

### Re: Naming compounds

In my AP Chemistry class, we were required to memorize the strong acids and bases and a list of polyionic compounds. While nothing has been explicitly said, I think it would be a good idea to just because of the prevalence of certain compounds in practice problems.
Sun Oct 25, 2020 6:20 pm
Forum: Molarity, Solutions, Dilutions
Topic: mmol
Replies: 14
Views: 170

### Re: mmol

mmol means millimole. If you want to convert it to moles, just multiply the amount of mmol by 10^-3. Also, think of it this way: don't let the fact that the base unit is a mol. Just remember the King Henry Died By Drinking Chocolate Milk acronym and use it to multiply or divide by 10^n when necessary.
Sun Oct 25, 2020 6:09 pm
Forum: Significant Figures
Topic: Sig Figs and Zeroes
Replies: 5
Views: 56

### Re: Sig Figs and Zeroes

When it comes to zeroes and the decimal place, just remember this. If there IS a decimal place, trailing zeroes are sig figs. This is regardless of if they are before or after the decimal place. If there is NO decimal place, trailing zeroes are not sig figs. So at the end of the day, it depends on t...
Sun Oct 25, 2020 6:02 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: for test 1
Replies: 14
Views: 223

### Re: for test 1

hello! I think this is the kind of situation in which you wont' necessarily be asked to define them on the test, but it's imperative to have a grasp on them. Much of the Fundamentals and related questions rely on these principles. I think it would be a good rule of thumb to memorize the constants li...
Sun Oct 25, 2020 10:21 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Measurements to Make Solutions
Replies: 2
Views: 67

### Measurements to Make Solutions

I was reviewing Fundamental E and came across this question in the textbook that asked "Why do chemists typically not measure out very precise, predetermined masses when making up solutions?" I'm just wondering if anyone knows the answer to this since I'd like to understand this topic more...
Sun Oct 18, 2020 8:25 pm
Forum: Properties of Light
Topic: Photons
Replies: 9
Views: 81

### Re: Photons

A photon is essentially a small subatomic particle of light that carries energy. They're found in wavelengths of light as packets of energy.
Sun Oct 18, 2020 8:23 pm
Forum: Properties of Light
Topic: Photon vs Quantum
Replies: 7
Views: 79

### Re: Photon vs Quantum

A photon is the smallest particle of light possible. Meanwhile, a quantum is the smallest possible particle at the subatomic level. I don't think they're interchangeable because the former carries a measure of energy while the latter is a measure of energy. However, they are very much related.
Sun Oct 18, 2020 8:03 pm
Forum: Properties of Light
Topic: Frequency vs Wavelength
Replies: 22
Views: 141

### Re: Frequency vs Wavelength

There is an inverse relationship with wavelength and frequency. When the wavelength is longer, the frequency is weaker because during a segment of time, the wave will hit a certain point less times than if the wavelength were shorter. On the other hand, when the wavelength is shorter, the frequency ...
Sun Oct 18, 2020 7:57 pm
Forum: Properties of Light
Topic: Photoelectric spectrum
Replies: 24
Views: 163

### Re: Photoelectric spectrum

I think it's a good idea to just have down them down in the order of, let's say, ascending or descending frequencies or wavelengths. In other words, don't necessarily memorize the specific numbers, but be aware of what on the photoelectric spectrum has a higher/lower frequency or wavelength with res...
Sun Oct 18, 2020 7:51 pm
Forum: Properties of Light
Topic: Intensity v Energy
Replies: 18
Views: 165

### Re: Intensity v Energy

I think energy in the context of light and wavelengths would be bundles of photons that travel in the light waves. Energy has to do with the frequency of the wavelength. It's characterized by the equation E= hcλ. On the other hand, intensity is defined as the power of light going through a unit area...
Sat Oct 10, 2020 9:46 am
Forum: Accuracy, Precision, Mole, Other Definitions
Replies: 31
Views: 369

One good rule of thumb is to remember the equation N=n(Na) with N being the amount of something (let's say molecules, atoms, etc.), n being the moles of that something, and Na being Avogadro's constant. If a question gives you a number of molecules or atoms or so forth and asks for the number of mol...
Sat Oct 10, 2020 9:32 am
Forum: Significant Figures
Topic: Which number determines sig figs of the answer?
Replies: 26
Views: 179

### Re: Which number determines sig figs of the answer?

This depends on the operation. When adding or subtracting, look for the value with the least amount of numbers in the decimal place. Your answer will have that same number of digits after the decimal point. For example, if you're subtracting 17.923-6.6, your answer will be 11.3. Note the single valu...
Sat Oct 10, 2020 9:24 am
Forum: Balancing Chemical Reactions
Topic: Fractions
Replies: 26
Views: 169

### Re: Fractions

I remember Dr. Lavelle saying to make sure that the coefficients in the chemical reaction are all whole numbers in one of the modules. While I'm not sure if you'll get points taken off, I'd just multiply them all out to be on the safe side. It also makes any conversions or calculations easier simply...
Sat Oct 10, 2020 9:21 am
Forum: Balancing Chemical Reactions
Topic: Order of Balancing Rxns
Replies: 23
Views: 115

### Re: Order of Balancing Rxns

I don't think there's a strict order to it. I personally just make a list of the number of each element on each side of the equation. If they're not equal, then I add numbers as necessary.
Sat Oct 10, 2020 9:19 am
Forum: Significant Figures
Topic: Sapling Question 2
Replies: 14
Views: 113

### Re: Sapling Question 2

You might be mixing up the fact that you're moving the decimal point to the left to change 291.7 into scientific notation. The first thing to keep in mind is that the mantissa must be greater than one but less than ten. For this specific case, it'll be 2.917. Now, if you were to put the exponent as ...