CHEMISTRY COMMUNITY

Kimiya Aframian IB

Having watched lecture twice on the 2nd order, I understand the steps but can not understand what it means lol . I better retrain when I understand so if anyone can help elaborate this concept I'll appreciate it. Second order means that there are two things that must collide, so the rate is depende...

Kimiya Aframian IB

When looking at a galvanic cell, if I have found delta G naught through the equation: delta G naught = -nFE nuaght. Can I then use this Delta G naught in the equation: Delta G naught = -RTlnK in order to find K? I thought I could, but everytime I use this method I get the wrong answer so I want to ...

Kimiya Aframian IB

6N.23 reads: (a) Suggest two metals that could be used for the cathodic protection of a titanium pipeline. (b) What factors other than relative positions in the electrochemical series need to be considered in practice? (c) Often copper piping is connected to iron pipes in household plumbing systems...

Kimiya Aframian IB

I was just wondering how to approach writing the half-reactions for redox reactions that have only one reactant. In those situations how do we know what is getting reduced or oxidized. For example in 6L.5 part (d) the reaction is Au+(aq)->Au(s)+Au3+(aq) and we are supposed to recognize that the hal...

Kimiya Aframian IB

When looking at a cell diagram, how do you tell which substances are reactants and which are products? Also, how do you know whether a substance that is included in the diagram is actually included in the half reactions? For example, question 6L.3 (d) asks for the half reactions of: Pt(s) | O2(g) |...

Kimiya Aframian IB

Hello, today in class Lavelle talked about solving for n and m which I believe are the reaction orders by doing experiment2/ experiment 1. I had a few questions about this. 1. Are we always going to be given the initial reaction rates or are we going to have to calculate them? 2. Later on in the le...

Kimiya Aframian IB

Calculate the equilibrium constants for the following reactions: (a) Mn(s) + Ti2+(aq)⇌Mn2+(aq) + Ti(s) Could someone walk me through how to do figure out a problem like this Hi! for this one we need to solve for E using the standard reduction potentials. Then we use the equation E=(RT)/(nF) *In(K),...

Kimiya Aframian IB

the rxn given is AgBr <--> Ag+ + Br- and I'm confused on how they got these half rxns, if someone could explain pls lmk!! thank you! Hi! For this one we know that we need to get as positive E knot cell so the E of the anode and cathode have to add to a positive value. Knowing this, we can see that ...

Kimiya Aframian IB

When do zero order reactions occur mathematically? Is that saying that the exponents that are associated with concentrations are all 0 and thus the concentrations of reactants do not affect the rate law? Or what is the meaning of a zero order reaction? Hi! I think the meaning of zeroth order is exa...

Kimiya Aframian IB

When Dr. Lavelle talks about the mechanism of a reaction, what does he mean? I know he said he wouldn't talk about it in depth until next week but i was just curious. Thanks! Hi! I think the mechanism is the steps in the reaction and what is occurring between the atoms/molecules on a molecular leve...

Kimiya Aframian IB

Hi! I am a little confused by this concept. What does the order of the reaction tell us? What is the difference between zero order, 1st order, and 2nd order reactions? Thanks! Hi! Mathematically the order is the exponent value and the overall order is the sum of the exponent values. Conceptually, t...

Kimiya Aframian IB

Anna Lockhart 2B wrote:Is it fair to say that larger molecules will always have more disorder than smaller ones?

Yes, I think this is true because when it is larger, there are more particles (ie. protons, neutrons, electrons) that can occupy different positions. Hope this helps!

Kimiya Aframian IB

How can an Isolated system be affected if it is isolated and nothing affects it? What kind of changes have to occur that affect it? I'm having a hard time understanding this still. Hi! An isolated system means that nothing can enter or exit the system (in the form of heat or matter), but that does ...

Kimiya Aframian IB

What is the definition of state property? Why are heat and work not considered as state properties? Hi! A state property is not dependent on the path that the system travels in reaching the end result, but instead it is only dependent on the final and initial conditions. I think of it as climbing a...

Kimiya Aframian IB

why is there a negative sign in front of n in the standard Gibbs energy equation? Hi! I think the negative sign in front of the n (mole value) is because it keeps the relationship between E, delta G, and spontaneity consistent. By this I mean that we need the E value to be positive when delta G is ...

Kimiya Aframian IB

Sunny Wu 3A wrote:In what scenario does -ΔS_surr=ΔS_system?

Hi! The scenario in which that statement is true is when delta S universe=0, which is for a reversible reaction because it is slow enough for the surroundings to restore the heat lost by work, therefore making the change in the universe 0. Hope this helps!

Kimiya Aframian IB

Do we need to be aware of any technical changes to the formula if we decide to use Kelvins vs Celcius in the calculations for temperature in both T1 and T2? Or should we just stick with Kelvin to be safe? Hi! I think that it is the most safe to use Kelvin but always try to check if there are any un...

Kimiya Aframian IB

Hi! I was wondering when we are able to and when we are not able to use the equation "change in entropy of system=qrev/T". For example, on question #9 of the weeks 5 & 6 sapling assignment, we used "change in entropy of surrounding=-qrev/T" to find the entropy of the surround...

Kimiya Aframian IB

For some of the problems in 4H of the textbook, I see them mentioning the number of “fundamental particles” of an element/compound when determining which compound will have the greater standard molar entropy. I was wondering what does it mean when it mentions fundamental particles and what part doe...

Kimiya Aframian IB

I just wanted to check, when using K in the thermodynamics equations, does it always stand for the equilibrium constant? Thank you! Hi! I think that K must be put into context for thermodynamics because it can be the unit of temperature K (Kelvin), k (also written as kb) for Boltzmann's constant, o...

Kimiya Aframian IB

I have a question relating to the following two questions: 4C.11 How much heat is needed to convert 80.0 g of ice at 0.0 8C into liquid water at 20.0 8C (see Tables 4A.2 and 4C.1)? 4C.13 An ice cube of mass 50.0 g at 0.0 8C is added to a glass containing 400.0 g of water at 45.0 8C. What is the fin...

Kimiya Aframian IB

This gives us a list of delta Hs for fusion and vaporization, and the specific heat capacities for the solid, liquid and gas phase. The C for solid and gas is 30 J/mol, and for liquid is 60 J/mol. When picking the correct heating curve for it, the answer key says that the liquid should have a less ...

Kimiya Aframian IB

Today in lecture Dr. Lavelle mentioned this concept. The limit as i approaches 0 gives the potential as a electromotive force of the cell. What is i in this concept?? Am I thinking about this correctly? Hi! I think that "i" is the transfer of electrons in the battery system because he sai...

Kimiya Aframian IB

4I.1 What is the total entropy change accompanying a process in which 40.0 kJ of energy is transferred as heat from a large reservoir at 800. K to one at 200. K? text.jpg The solutions manual uses q/t which makes sense but can someone explain why one of the calculations is negative and the other is...

Kimiya Aframian IB

can someone explain why NO is likely to have a residual entropy in their crystalline forms at T = 0K for #1 in the sapling week 5/6 hw? i don't really understand the solution explanation and at first, i didn't think the orientation of N and O really differed enough in NO to reach that conclusion ._...

Kimiya Aframian IB

The book explains that a reversible process is one that can be reversed by an infinitely small change in variable. It later says "Expansion against an external pressure that differs by a measurable amount from the pressure of the system is an irreversible process in the sense that an infinites...

Kimiya Aframian IB

For Problem 4A.3 in the textbook, when calculating for the change in volume, the answer key multiplied by 1L=1000cm^3. I was wondering how we would know that 1L is equal to 1000 cm^3 based off of the equation sheet. Hi! One way to know this is to think about how 1 mL=1 cm^3, so you could convert 1 ...

Kimiya Aframian IB

Hey guys! I'm struggling a bit with picking which R value to use (8.314 J mol^-1 K^1 versus 0.08206 L atm mol^-1 K^1). I'm assuming that we use 0.08206 whenever we do a calculation with atmosphere as units like in most PV=nRT problems. Is that correct? Hi! I think the best way to check which R valu...

Kimiya Aframian IB

Lily Mohtashami wrote:What is the difference between the change in enthalpy at constant pressure and constant volume?

Change in enthalpy and constant pressure and constant volume is different because of the difference in the heat capacities for constant pressure and constant volume. Hope this helps!

Kimiya Aframian IB

When a problem says the reaction is isothermal, do we assume it occurs on a reversible pathway as well? Hi! Yes, when an reaction is isothermal it is also on a reversible pathway because it is occurring at a constant temperature which is seen in reactions that have are slow enough for the energy an...

Kimiya Aframian IB

For some questions on sampling week 2, where we would have a number like .032-x and equal it to Kb for an example, when is it fine or restricted to assume x is so insignifcant we can keep it out? Hi! A general rule for knowing when assuming x is insignificant is okay is if the k value is less than ...

Kimiya Aframian IB

What does phase change mean specifically? Or is it just a solid changing into a liquid? Hi! A phase change is a change in the state of matter, meaning the transition between a l to a g, s to l, g to s, etc. While phase changes don't necessarily have changes in temperature, they do have changes in i...

Kimiya Aframian IB

For question 11 on sapling, it asked about which systems do work on the surroundings when there is constant pressure and one of the answers was this A(s)+B(g)⟶2C(g)? isn't that 2moles⟶2moles so doesn't that equal? or am I misunderstanding this? Hi! The key detail is that we must focus on only moles...

Kimiya Aframian IB

I understand the difference between open, closed and isolated systems, but what is the significance of recognizing and understanding what type of system a reaction is when answering problems and doing calculations? Does the type of system affect what must stay constant in a reaction? What informati...

Kimiya Aframian IB

Why is water condensing on a surface an exothermic reaction? Hi! The reason that water condensing on a surface is an exothermic reaction is because it is a phase change from gas to a liquid (the opposite of vaporization) and it releases heat (and therefore energy) into the surroundings. The change ...

Kimiya Aframian IB

Hi, Can anyone explain what is a reversible system and what is an irreversible system? Dr. Lavelle uses an example of if the difference of pressure between the outside and the inside is infinitesimal, then it is a reversible system, and we should use integral and derivatives, but I am still confuse...

Kimiya Aframian IB

Hey everyone, I'm confused on why the molar concentration of Ba(OH)2 and Ba2+ are equal to each other? The rest of them make sense but why are these two equal? I attached the question and solution for reference! Thanks! Hi! Ba(OH)2 would have the same molar concentration as Ba2+ because we would se...

Kimiya Aframian IB

Talia Leano 2H wrote:What is total pressure?

Hi! The total pressure is the sum of all of the partial pressures, so you would add them together. Hope this helps!

Kimiya Aframian IB

hey! this question asks to calculate the pH, pOH, and % protonation. part a.) is "0.057 M NH3" I set up the equation for the proton transfer equilibrium, and then I set up an ICE table to determine that Kb = [OH-][NH4] / [NH3], and then I plugged in my ICE expressions to get Kb = x^2 / (0...

Kimiya Aframian IB

Professor mentioned in his lecture that the reaction of HCl and NaOH is neutralization reaction What is neutralization and what makes that reaction one of it? Hi! A neutralization reaction is when a strong acid and strong base react. They will form a water and a salt, which makes these two products...

Kimiya Aframian IB

Professor mentioned in his lecture that the reaction of HCl and NaOH is neutralization reaction What is neutralization and what makes that reaction one of it? Hi! A neutralization reaction is when a strong acid and strong base react. They will form a water and a salt, which makes these two products...

Kimiya Aframian IB

Sameer Gupta 2F wrote:Why is sublimation an endothermic reaction?

Hi! Solid is a change from solid to a gas, so that would require that bonds are broken which requires energy and is therefore endothermic. Hope this helps!

Kimiya Aframian IB

Does anyone know why when creating ICE charts, and we have a decrease of "-2x" we still have to include the "2" as an exponent when writing out the constant equation? For example, if my product is -2x, and whenever it's time to calculate either K or for X, we would then do produ...

Kimiya Aframian IB

Hi, can someone explain the heating curve and how that applies to why steam causes severe burns? Dr. Lavelle explained in one of his lectures but I'm still a little confused. Hi! The heating curve explains how steam burns worse than water because while they may be at the same temperature, steam has...

Kimiya Aframian IB

Neha Gupta 2A wrote:Is there a difference between vapor and gas or are they the same thing?

Hello! Vapor and gas can be used interchangeably. Hope this helps!

Kimiya Aframian IB

Neha Gupta 2A wrote:Is there a specific formula for percent ionization? Is it [H3O+]/[HA] or [conjugate base]/[HA]?

Hello! To calculate the percent ionization, you can use the formulas that you have supplied, where conjugate acid/base is divided by initial acid/base and then multiplied by 100%. Hope this helps!

Kimiya Aframian IB

Is there a method to identifying which acids & bases are strong or weak, or is it something we just have to memorize? Is there a pattern on the periodic table that tells us? Hi! In general, it's easiest to memorize which acids/bases are strong so that when presented with a list of acids, the st...

Kimiya Aframian IB

The kb for an amine is 3.056×10−5. What percentage of the amine is protonated if the pH of a solution of the amine is 9.249 ? Assume that all OH− came from the reaction of B with H2O. Can someone help me start this problem? Thank you! Hi! The first thing for this problem would be to change the pH v...

Kimiya Aframian IB

Are the numbers at the top of the phase diagram that go horizontally across the change in enthalpy when water goes from solid to liquid and liquid to vapor? If so, why are there three numbers if there are only 2 phase changes? Hello! The horizontal numbers on the phase diagram are the changes in en...

Kimiya Aframian IB

In the textbook their are problems where we are solving for the pH of a polyprotic acid and it is advised to ignore the 2nd deprotanation of weak polyprotic acids because Ka2 is significantly less than Ka1. The only instance where we looked at the second deprotonation was for H2SO4 because it is a ...

Kimiya Aframian IB

In lecture, Dr. Lavelle defined Kw as the equilibrium constant for water, which was always equal to 1.0 x 10^-14 at 25 degrees C. Does this mean that the equilibrium constant of water would be different for different temperatures? Also, is the water only considered neutral when [H3O+] and [OH-] are...

Kimiya Aframian IB

Many of the textbook problems in Focus 5 refer to table 5G.2, which is a table of the equilibrium constants for different reactions at different temperatures. There is both a K column and a Kc column, and sometimes those values are the same for a reaction and sometimes they're different. Can someon...

Kimiya Aframian IB

Hi! In todays lecture, Dr. Lavelle mentioned in an example that the reaction with a very small equilibrium constant lies very far to the left. Is it it true to say that reactions with very small equilibrium constants lie to the left and reactions with very large equilibrium constants lie to the rig...

Kimiya Aframian IB

Victoria Dao 3G wrote:When we're given the Kw value and either the concentration values of OH- or H3O+, do we have to add the stoichiometric coefficient as the exponent when solving for the missing concentration?

Hi! That is definitely true, however it exponent will be one. Hope this helps!

Kimiya Aframian IB

Juwan_Madaki_3K wrote:Why do you multiply the equilibrium constants instead of adding them?

Hi! You multiply the equilibrium constants because you are adding the equations together to form the new equation. Hope this helps!

Kimiya Aframian IB

In the example in at the beginning of Lecture 4, Dr. Lavelle said that since Kc is very small we can approximate that the concentrations of the compounds will stay roughly the same, and this is how we would calculate X to figure out the composition of the equilibrium mixture. Would Kc always be sma...

Kimiya Aframian IB

Can someone briefly explain the relationship between Q and K. Like what it means when one is bigger than the other and also what the difference between them is. Thanks. Hi! K is the equilibrium constant (the ratio at the equilibrium point) and Q is the ratio calculated at any point of the reaction ...

Kimiya Aframian IB

Why does K change when the temperature changes in a reaction? Hi! A change in temperature causes the K value to change because the reaction will want to counteract the change in temperature by either increasing or decreasing the amount of product/reactant depending on if the reactant is exo- or end...

Kimiya Aframian IB

Sophia Dinh 1D wrote:When do we include H2O and when do we exclude it from the ice table

Hi! H20 is only included in the ICE table and K calculations when it is in the gas or aqueous form. This rule also applies for other reagents. Hope this helps!

Kimiya Aframian IB

Can someone please explain the step-by-step process for this question? Especially for the last 2 equations, thank you! Hi! For the first one, we see that the equation is the inverse of the given, so the K value will also be the reciprocal of the original k. This means it will be 1/41. For the secon...

Kimiya Aframian IB

When they are calculated, are Kc and Kp the same value? I know one deals with concentration while other deals with pressures. I was curious if the values turn out the same. If they aren't the same, then what would we use each equilibrium constant for? Hi! The Kc and Kp values are calculated in the ...

Kimiya Aframian IB

How do we know whether to be labeling the change as a positive or negative in the ice boxes? Does it depend on the initial concentration we are given/not given? Hi! The change in the ICE boxes will be negative if the specific reagent is decreasing in value. Whenever the products have an initial val...

Kimiya Aframian IB

Hi everyone! I had a general question about oxidation numbers. When we're determining the oxidation number for the transition metal, are we taking into account the whole compound or do we just take into account the coordination compound. I had always done the latter, but when I was reviewing Dr. La...

Kimiya Aframian IB

Constance Newell wrote:Is wavelength always converted into m or are there any instance where wavelength must be in nm?

When doing calculations, it usually needs to be in the SI unit of m. It may ask for a conversion in the end of the problem though. Hope this helps!

Kimiya Aframian IB

Nan_Guan_3J wrote:quick question, does it mean that the chemical bonds are more stable if the bond angel is larger?

Hi! I think this is true because of the repulsion between electrons, so the bonds will be as far apart as possible. Hope this helps!

Kimiya Aframian IB

2F.3. How many sigma-bonds and how many pi-bonds are there in a) H2S ? b) SO2 ? How do you find how many sigma and pi bonds there are in a molecule? Please help and thank you! Hi! When you draw the structure for H2S there will be two single bonds, meaning there will be two sigma bonds. For S02, the...

Kimiya Aframian IB

What are the differences between sigma and pi bonds and how can you recognize them in examples or pictures? Hi! Sigma bonds are formed when there is a single bond and head to head interaction. Pi bonds are formed when there is a double or triple bond and side by side interaction. In a single bond, ...

Kimiya Aframian IB

Are Bronsted acids usually Lewis bases, and Bronsted bases usually Lewis acids? I'm not sure if I'm understanding this correctly. Thanks! Hi! Bronsted bases are also Lewis bases, and Bronsted acids are also Lewis Acids. The difference between the two is that Bronsted definition discusses protons wh...

Kimiya Aframian IB

Jordi M 2F wrote:Is there a pOH scale that would also go from 0 to 14 like pH?

Hi! There is a pOH scale from 0 to 14, but it is important to note that in this case, a pOH of 0 would be the most alkaline base, while 14 would be the most acidic acid. Hope this helps!

Kimiya Aframian IB

Does electronegativity play any role in hybridization? Hi! I don't think that electronegativity and hybridization are directly connected because electronegativity is about the attraction of electrons while hybridization is more focused on the formation of bonds and the sharing of orbitals. Hope thi...

Kimiya Aframian IB

Hi, I am still confused on understanding the concept of hybridization. Does anyone know how to simply determine the hybridization of an atom? Hi! To determine the hybridization, you want to make sure the total number of s,p,d,and/or f orbitals add up to the total number of bonds. For example, if th...

Kimiya Aframian IB

Hi! 9C.1 in the textbook asks to name the complex ion with the formula [Fe(CN)6]4- and the answer is hexacyanoferrate (II) ion. Why is it "cyano" and not "cyanido" ? Hi! Cyano is the older way while cyanido is the newer version. Dr. Lavelle said that we can use either one but he...

Kimiya Aframian IB

What are the differences between sigma and pi bonds and how can you recognize them in examples or pictures? Hi! sigma bonds are head to head bonds and they occur in every type of bond (single, double, triple). Pi bonds are the additional bonds on double and triple bonds, so a double bond will have ...

Kimiya Aframian IB

How can you recognize the charge or oxidation state of individual atoms/molecules in a coordination compound? For example, in lecture Dr. Lavelle stated that in [Ni(CN)4]2- , the CN molecule has a -1 charge, and so the Nickel must have a 2+ charge to make a total charge of 2-. Hi! To determine the ...

Kimiya Aframian IB

What is the easiest way to identify anions from a chemical formula when naming a coordination compound? Hi! The anion has the negative charge, so this will be known either from the periodic table, knowledge of the charges of polyatomic ions, or process of elimination based on the charges of the oth...

Kimiya Aframian IB

I was having some trouble drawing lewis structures recently because I would often find myself with (usually 2) extra electrons. After I had already filled the outer elements to 8. It was in a recent lecture that Dr. Lavelle put the lone pairs on the elements in the middle and I never thought to do ...

Kimiya Aframian IB

nina fukui 1G wrote:Hi everyone,
What does isoelectronic mean?

Hi! Isoelectronic means that the two entities (ie. atoms, ions, molecules, etc.) have the same number of electrons. This does not mean they have the same characteristics or the same charge. Hope this helps!

Kimiya Aframian IB

Nane Onanyan 1H wrote:Why is CH2Cl2 polar?

Hi! CH2Cl2 is polar because it is not perfectly symmetrical so the dipole moments between the different atoms will not cancel out and parts of the molecules will be more partially positive/negative than other parts. Hope this helps!

Kimiya Aframian IB

Can someone list the factors affecting covalent bond length and explain the effect of each? I am reviewing the outline and would love to add onto what I already know and make sure I understand everything. Hi! Covalent bond length is directly related to the strength of the bond. This means that if i...

Kimiya Aframian IB

Can someone explain why SF2 is not linear? I thought there will be one lone pair above the S atom, and another lone pair below it, making it a linear shape. Thank you in advance! Hi! You are absolutely correct that there will be two lone pairs and two bonded pairs on sulfur, however this does not c...

Kimiya Aframian IB

What exactly is a dipole? Is a dipole anything that is covalently bonded that has an imbalanced charge? Like anything that is polar? Hi! A dipole is essentially a charge and when we say that an atom/molecule has a dipole it means that the electrons are not evenly shared between the atoms so there i...

Kimiya Aframian IB

When writing electron configurations, do we always write the 3d before the 4s? Also, why does the way we fill the orbitals change when we get to the d-block since K and Ca go from 3p to 4s, but something like Sc would be [Ar]3d1 4s2? I'm confused because I'm seeing mixed explanations online, thanks...

Kimiya Aframian IB

If an N,O, or F atom hypothetically has 2 lone pairs, is it capable of creating 2 hydrogen bonds, one for every lone pair, or just one hydrogen bond. In other words, does the number of potential hydrogen bonds for an atom depend on the number of lone pairs that atom has? Hi! If there are potentiall...

Kimiya Aframian IB

Is it true that a quick way to identify radicals without drawing Lewis structures is by just seeing if the molecule has an even or odd number of valence electrons? Does this work all the time? Hi! I'm pretty sure that this is a good and quick way to identify if there is a radical but it is always s...

Kimiya Aframian IB

Out of curiosity, which would have lower ionization energy, Cl or O? If it were to ever be needed in making a Lewis structure. Hi! I would say that Cl has a lower ionization energy than O because it is in a lower period than O is. When making a Lewis Structure, if it has multiple of one of these an...

Kimiya Aframian IB

Hi! I'm having difficulty with problem 13 in sapling assignment. The problem asks: what is the maximum theoretical number of water molecules that one urea molecule can hydrogen bond with? How can I solve this? Hi! For this problem you need to consider the circumstances that allow for hydrogen bondi...

Kimiya Aframian IB

What exactly is an electric dipole moment and how do we calculate it? Also, how do we know the magnitude of the charge in dipoles? Hi! The electric dipole moment can be calculated by multiplying the charges and then dividing by the distance between the two molecules. I don't think we will need to b...

Kimiya Aframian IB

Hi! I was doing Sapling homework #6 which asks us to identify which molecules out of a list are lewis acids and lewis bases. I understand that a lewis acid is an electron pair acceptor while a lewis base is an electron base donor, but the homework is saying that SO2 is a lewis acid. Why is that true...

Kimiya Aframian IB

Are the amount of questions on midterm 2 going to be roughly the same amount as the amount of questions on midterm 1? Hi! I think there will be more questions on MT 2 based on a recent email from Dr. Lavelle. He also said that they will take less time to complete so it would balance out in terms of...

Kimiya Aframian IB

Can someone explain in simple terms why double bonds are shorter than single bonds? Double bonds are shorter than single bonds because together, they are stronger and can pull the two atoms closer together. Because the atoms are closer together resulting in the increased strength of the double bond...

Kimiya Aframian IB

how do we know when something is delta + or - at the end of lecture today, professor did H-o-H and he said O was delta - how did he know? thank you Hi! We know that O is delta negative because it has a higher electronegativity than H does, so it will pull the electrons towards it, therefore giving ...

Kimiya Aframian IB

I just did Sapling #9 and I was wondering if all oxidation numbers are ionic? As in, when oxygen is in an equation, the oxidation numbers assume the bonds are more ionic than covalent because the non-oxygen atom has a positive charge to balance out the oxygen's negative charge? Hi! The reason this ...

Kimiya Aframian IB

Can someone explain how C has 4 valence electrons (I'm looking at the Sapling exercise that says this). I thought the group number tells you the number of valence electrons, and C is in group 2. Hi! C has 4 valence electrons. Personally, I like to count how many there are by starting with group 1 a...

Kimiya Aframian IB

I remember Dr. Lavelle referring to covalently bonded elements as molecules and ionically bonded elements as compounds/salts. Does this mean compounds can't be covalently bound and molecules can't be ionically bound (are they exclusive?)? Hi! I don't think they are exclusive because if I am remembe...

Kimiya Aframian IB

How do we identify if a neutral molecule is a Lewis Acid or Lewis Base? I am familiar with identifying Lewis Acids and Lewis Bases when there is a charge on a molecule like for polyatomic ions, but how do you know if a molecule is a proton acceptor or proton donor when there is no charge? Hi! I thi...

Kimiya Aframian IB

If you were to write the electron configuration for a noble gas element, would it be appropriate to use the noble gas configuration? For example, could you write Argon as just [Ar], or would you need to write it from the previous noble gas, [Ne]3s 2 3p 6 ? Hi! I think that either way should work. I...

Kimiya Aframian IB

Katherine Brenner 3H wrote:When you calculate a formal charge and get 1- will that be a formal charge of +1 or -1 because it is an electcron?

Hi! Formal charge can be positive, negative, or neutral, and in this case it would be negative. Hope this helps!

Kimiya Aframian IB

Hello, Professor said in the lecture that 4s is very close in energy with 3d and states in the slide, "NOTE: 4s before 3d." What does this mean? Hi! I think this means that we would fill up the 4s orbital before 3d in terms of order on the periodic table. It could also mean that we should...

Kimiya Aframian IB

If there are 3 or more elements in a molecule, I was wondering how you know which atoms are bonded together. For example, in COCl2, O and Cl are bonded to C. How do we know that Cl and C aren't bonded to each other? Sorry, I don't know if I am asking clearly... Hi! I think that Lavelle mentioned it...

Kimiya Aframian IB

Algernon Jackson 2l wrote:Do gamma rays have the longest wavelength?

Hi! Gamma rays have the shortest wave length, and thus the highest frequency and highest energy. Hope this helps!

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