CHEMISTRY COMMUNITY

Maya Beal Dis 1D

I am guessing it will be more than the three hour period because we will most likely need to print out a sheet and upload it and everything.

Maya Beal Dis 1D

Are all review sessions going to be cancelled?

Maya Beal Dis 1D

Is it possible he will have us take the final in small group settings on campus or are we okay to go home and assume everything for the rest of the quarter can be completed online?

Maya Beal Dis 1D

Will there be a way for us to get them back and review them before the final?

Maya Beal Dis 1D

I think the states would be the same you are just balancing the coefficients based on the number of electrons transferred so the electrons are equal in each reaction.

Maya Beal Dis 1D

If you are using the shortcut E=E(naught)-(0.05916/n)logQ, you need to use log. I think there is another number shortcut if you are using the equation with natural log.

Maya Beal Dis 1D

How do you know when an inert electrode is needed in a galvanic cell?

Maya Beal Dis 1D

In the equation lnK=nFE/RT, which value do you use for R and how do the units cancel out?

Maya Beal Dis 1D

The standard cell potential in a concentration cell is zero because the two half cells would be identical under standard conditions.

Maya Beal Dis 1D

Will the first page of thermodynamics not be on test 2?

Maya Beal Dis 1D

A battery dying or being used is releasing energy and therefore favorable, so the reverse reaction (charging the battery) would not be favorable.

Maya Beal Dis 1D

In lecture didn't Lavelle say that the voltage is typically lower with the porous disk in a concentration cell?

Maya Beal Dis 1D

In problem 5G.13 you calculate the delta G of the reaction at equilibrium and then use whether that value is positive or negative to see which way the reaction will proceed (towards reactants or products), but if the reaction is at equilibrium doesn't that mean the reaction is going both ways at the...

Maya Beal Dis 1D

Does this mean that material covered before the midterm will not be on test 2 at all?

Maya Beal Dis 1D

The charge of a molecule is always equal to the sum of the oxidation numbers multiplied by the amount of each element, so you can use the net charge to determine oxidation numbers.

Maya Beal Dis 1D

Extensive properties include volume, mass, and weight. Intensive properties include temperature, boiling point, and color.

Maya Beal Dis 1D

An adiabatic system is defined as a system in which no heat transfer can take place so q is zero.

Maya Beal Dis 1D

The sum of the oxidation numbers in a molecule must equal the overall charge.

Maya Beal Dis 1D

Would this mean that the change in enthalpy for an adiabtic process is also zero?

Maya Beal Dis 1D

When are the posts due every week? Is it Friday or Sunday?

Maya Beal Dis 1D

It delta G is positive it means the reaction is spontaneous in the reverse direction.

Maya Beal Dis 1D

A very general explanation is that systems tend to want to be in the lowest energy state and when a reaction is exothermic it loses energy as heat.

Maya Beal Dis 1D

Isobaric is constant pressure, isochoric is constant volume, and isothermal is constant temperature.

Maya Beal Dis 1D

You can tell that heat capacity is an extensive property because the units are Joule/Kelvin. Because there is no mass value in the units, it is not dependent on the amount of substance present. The units for specific heat are Joule/gram*Kelvin which do include mass values and are therefore dependent...

Maya Beal Dis 1D

My solutions manual shows the way to solve this problem is by using the equation U=H+nRT, but no value for temperature is given in the problem. The solutions guide uses the value of 298 K for the temperature. Will there ever be an instances on the midterm where we will need to assume standard temper...

Maya Beal Dis 1D

Do we need to memorize the table in the textbook that tells you which fraction to multiply R by based on if the reactant is an atom or molecule and so forth?

Maya Beal Dis 1D

Why does supercooling and superheating occur and will we need to be able to explain it on the midterm?

Maya Beal Dis 1D

What is the difference between reversible and irreversible work and how can you tell by looking at an experiment whether it is reversible or not?

Maya Beal Dis 1D

Almost all gases that you use in an experiment would be non-ideal, but it is easier to do calculations with ideal gases.

Maya Beal Dis 1D

Why is the enthalpy larger? Aren't the same type of bonds being broken?

Maya Beal Dis 1D

When adding and subtracting you round to the value place of whichever component has the largest value for it's significant figures, where in multiplication and division you count the number of significant figures and ignore their place values.

Maya Beal Dis 1D

A bomb calorimeter is an example of an isolated system because no energy or matter can be lost or gained.

Maya Beal Dis 1D

So is an ice cube melting an example of an exothermic or endothermic reaction? Because the temperature of the water final is greater than the initial temperature and the difference would therefore be positive is it an endothermic reaction?

Maya Beal Dis 1D

Inert gases are inert and thereby do not react with any of the other gases in solution.

Maya Beal Dis 1D

Something is a state property if the value can be obtained just by looking at the final and initial conditions.

Maya Beal Dis 1D

If you were unsure as to if x is a small enough value to ignore you could also just solve the problem as you usually would and get a correct answer it would just be more work.

Maya Beal Dis 1D

You should also know how to convert between pKa, Ka, pKb, and Kb.

Maya Beal Dis 1D

Increasing the pressure of a system by adding an inert gas would not shift the reaction either way because the gas is inert and therefore does not react with anything else.

Maya Beal Dis 1D

Are pure liquids and pure solids always left out of the ICE box equations?

Maya Beal Dis 1D

A change in temperature is the only factor that can change K, but a change in concentration or pressure will shift Q.

Maya Beal Dis 1D

Are noble gases the only inert gases?

Maya Beal Dis 1D

Will we be done with acid/base equilibrium by the end of Friday's lecture and will that whole section be covered on the test?

Maya Beal Dis 1D

In lecture on Wednesday Lavelle showed us how to approximate when using ICE tables so you do not have to use the quadratic equation. Are we allowed to use this approximation on a test assuming it is less then 5% the initial value or would we need to use the quadratic equation to receive full credit?

Maya Beal Dis 1D

When would we need to specify and use Kc as opposed to just using Keq?

Maya Beal Dis 1D

Would a solution that is just a solute in water have a K value?

Maya Beal Dis 1D

My TA confirmed that posts are due by Sunday night.

Maya Beal Dis 1D

What is the difference between the reaction quotient and the equilibrium constant?

Maya Beal Dis 1D

Do we have to write Kp or can we just write K? My solutions manual only writes K.

Maya Beal Dis 1D

Would it be possible that the final curve of the overall class would make it so you need higher than a 93% to get an A? Would he curve the class up?

Maya Beal Dis 1D

I would recommend taking notes from the textbook on sections you have trouble doing the practice problems from as well.

Maya Beal Dis 1D

Does a double bond mean that the atom double bonded in a ligand cannot be the atom bonded to the central atom in a coordination complex because it can't rotate?

Maya Beal Dis 1D

Do we need to have the full name of edta memorized or can we just remember the abreviation?

Maya Beal Dis 1D

Would it always be the two single bonded oxygens that bond to the central atom? Could it be one of the double bonded oxygens and one of the single bonded ones?

Maya Beal Dis 1D

Does bent mean the same thing as angular? In the textbook they use the term angular and I was sure what that meant.

Maya Beal Dis 1D

I think if this were to be on a test it would most likely ask you to identify if the molecule is cis or trans and the effect that would have on the bonding/function of the molecule.

Maya Beal Dis 1D

To clarify, that would mean there are four regions of electron density making the electron arrangement of the central atom tetrahedral.

Maya Beal Dis 1D

In the textbook it says to treat the single electron on a radical as a region of electron density. The single electron would be less repulsive than two electrons in a lone pair and would effect bond angles less because of that. Still it would count as a single region of electron density.

Maya Beal Dis 1D

Yes, since the molecule has two regions of electron density the electron arrangement would be linear as would the shape.

Maya Beal Dis 1D

How do you know if they Cl atoms are across from each other or each across from a hydrogen atom when drawing the Lewis structure? Wouldn't this effect polarity?

Maya Beal Dis 1D

In part b of homework problem 2E.15 how do you determine the bond angles in the see-saw structure?

Maya Beal Dis 1D

If there is a central atom with two bonding regions and one lone pair what shape is it?

Maya Beal Dis 1D

What qualifies as the shape bent and what is angular? Are they the same thing?

I think in lecture Lavelle referred to a central atom with two bonding domains and two lone pairs as bent, but in the textbook they've been using angular as the shape name.

Maya Beal Dis 1D

What are the different synonyms for electron arrangement v. the molecular domains? If a question just asked for structure/shape should you only give the molecular domain name as opposed to the electron arrangement?

Maya Beal Dis 1D

Do we still have our discussion sections on week 9 if they are earlier in the week like Tuesday or Wednesday?

Maya Beal Dis 1D

I believe exam 2 will cover everything Lavelle has covered since the material which was included on the midterm. I think it begins with correcting the ionic and covalent models with polarizability and dipole moments and also includes the intermolecular forces we have been going over such as London f...

Maya Beal Dis 1D

A general pattern for bond strength from strongest to weakest is ion-ion interactions (ionic bonds), ion-dipole interactions, dipole-dipole interactions, dipole-induced dipole interactions, induced dipole-induced dipole interactions.

Maya Beal Dis 1D

In terms of bonding, the stronger the bonds between molecules the more solid a structure it will form, meaning stronger bonds are created in the formation of solids than liquids and liquids than gases. Varying viscosity in liquids is also caused by bond strength.

Maya Beal Dis 1D

Chemical bonding will be covered in test 2 so I'm sure it is okay to include them in week 7 homework.

Maya Beal Dis 1D

In lecture on Monday he said he doesn't use multiple choice problems because there is no partial credit so I believe it will all be free response.

Maya Beal Dis 1D

On Professor Lavelle's website it says to bring a pen, scientific calculator, and your student ID and nothing else. I believe it will be on regular printer paper like test one was as opposed to in a blue book or on a scantron so you shouldn't need either of those.

Maya Beal Dis 1D

What is the difference between an instantaneous dipole moment and a dipole-induced-dipole interaction?

Maya Beal Dis 1D

How many resonance structures would be be required to draw on a test like in the instance where a molecule has four or more possible resonance structures? Would we get credit if we identified the majority of them?

Maya Beal Dis 1D

In homework problem 2C.5 part c you are told to draw the structure of ClONO2 and determine or not if it is a radical. In my structure I have the Cl, O, N, and O atoms bonded in a chain with all single bonds and the last O atom bonded to the N with a double bond. This is the answer given in the book,...

Maya Beal Dis 1D

In homework problem 2C.5 part c you are told to draw the structure of ClONO2 and determine or not if it is a radical. In my structure I have the Cl, O, N, and O atoms bonded in a chain with all single bonds and the last O atom bonded to the N with a double bond. This is the answer given in the book,...

Maya Beal Dis 1D

Will radicals be covered on the midterm? Also, in homework problem 2C.5 you are asked to draw the Lewis Structure and determine is the molecule is a radical. For part a ClO-, how would you know that the one unpaired electron would be on the oxygen atom as opposed to the chlorine? Is there any way to...

Maya Beal Dis 1D

Ions can be in ground state too even though they have a net charge. It just means that all of the electrons on the atom are in the lowest possible energy state for that number of electrons.

Maya Beal Dis 1D

For part e of this problem, why is the ground state electron configuration [Ar]3d8 as opposed to [Ar]3d64s2? If an element is in the d block, is the (n-1)d shell always filled before the ns shell?

Maya Beal Dis 1D

This question asks you to determine the empirical formula of the ionic compound that would be formed if these two elements were to form an ionic bond. To do this you should find each element on the periodic table and determine the charge that element usually assumes based on it's valence electrons. ...

Maya Beal Dis 1D

For part d of this problem, why would an electron be removed from the 4s subshell as opposed to the 3d subshell? Wouldn't it be more stable to remove and electron from the subshell that is already only partially filled as opposed to removing an electron from the filled 4s shell?

Maya Beal Dis 1D

It helps me to think of which block on the periodic table the element sits in. If the element is in the third row of the p block, the valence electron will generally be removed from the 3p shell.

Maya Beal Dis 1D

In class I think he mentioned that you can't use electromagnetic radiation equations on electrons. What exactly does this mean?

Maya Beal Dis 1D

Is this the last homework we will turn in under the quantum unit?

Maya Beal Dis 1D

In problem 1B.21 you must know the conversion between miles per hour and meters per second. Are these conversion factors something we must memorize or will test problems always be given in SI units?

Maya Beal Dis 1D

In some of the homework problems you need to know the mass of an electron, neutron, or proton to use the DeBroglie equation and find wavelength. Do we need to have these masses memorized or would they be given on a test?

Maya Beal Dis 1D

What is an eV and are we required to know the conversion between that and a Joule?

Maya Beal Dis 1D

102.6 nm is part of the UV spectrum so you know you are using the Lyman series. You first divide the speed of light by the wavelength given to get frequency. You then rearrange the Rydberg Equation and use your calculated frequency to determine n2 is 3.

Maya Beal Dis 1D

I think we will be getting graded tests back in our discussion sections on week 3.

Maya Beal Dis 1D

What does it mean that the principle quantum number for the lowest energy level is the same for each series?

Maya Beal Dis 1D

What is the relationship between the amplitude of a wave and the frequency? Or the relationship between amplitude and wavelength? What does amplitude tell us exactly?

Maya Beal Dis 1D

In homework problem 1.A.3 it asks if the extent of change in the electrical field at a given point decreases as the frequency of electromagnetic radiation decreases. I understand that as the frequency decreases the slope of the wave also decreases, but what roles does amplitude play in the extent of...

Maya Beal Dis 1D

If in a problem it says it is a combustion reaction, that is how you know the products will be water and carbon dioxide. Often in combustion reactions the question will not give that information directly.

Maya Beal Dis 1D

When using dimensional analysis, when you round it in the end make sure you round it to the same amount of significant figures as the value with the least amount of significant figures that you used in you calculations.

Maya Beal Dis 1D

Does it matter which subsection the homework problems we are doing are from as long as they are within the quantum mechanics section (like 1A v. 1B v. 1D etc.)?

Maya Beal Dis 1D

Since the Quantum Unit is more than a week long does it mean we just hand in five homework problems from that section every week until we are done with the unit?

Maya Beal Dis 1D

Are we really only allowed to use pen on the test? What happens if we make a mistake on the paper, can we get scratch paper or extra pieces of paper? There is plenty of room on the test to solve the problems. You are allotted at least half a sheet per problem which I found to be enough even with so...

Maya Beal Dis 1D

You could also write it as 12000 because that also uses only 2 significant figures. Any zeros to the right of a whole number are not considered significant figures.

Maya Beal Dis 1D

Do we need to have the formulas and charges of polyatomic ions and their charges memorized or will they be given on a test? For example in textbook problem G.5 you are unable to solve the problem unless you know the molecular formula of sodium carbonate. Will there be problems like this on the test?

Maya Beal Dis 1D

When would you need to specify a molecule as anhydrous? I know most often that is the state molecules are in, but when naming compounds when must you include anhydrous in the written name?

Maya Beal Dis 1D

In what instances would a molecule be liquid as opposed to aqueous? What are some examples of molecules besides water that are in the state of pure liquid and not aqueous?

Maya Beal Dis 1D

How many of the naming rules do we need to know for the test next week? Do we need to have the names and charges of polyatomic ions memorized or will they be given if needed to solve a problem?

Search found 100 matches