CHEMISTRY COMMUNITY

Keirsten Andersen 3L

Why on this question is there a 1/2 in front of the m*deltaH? Isn't the equation always q=m*C*deltaT+m*deltaH? I don't understand the vaporization term used here.

Keirsten Andersen 3L

The possible answers to name this cycloalkene with 4 methyl substituents is either 2,3,4,4 tertmethylcyclohex-1-ene or 1,5,5,6 tetramethylcyclohex-1-ene. Since the double bond is #1 in both cases wouldn't we prefer the other numbers to be 2,3,4,4 since they are almost all lower than 1,5,5,6?

Keirsten Andersen 3L

Given the initial concentration of a product, reaction quotient, time, and change in concentration of product, how do we find the reaction rate? This solution takes the change in concentration and divides it by the time but what does the change in product have to do with the reaction rate?

Keirsten Andersen 3L

Q3A asks for the balanced redox equation of: MnO2(s) + ClO-(aq) -> MnO4^2-(aq)+Cl-(aq). The solution given balances the oxygens in the equation using OH- and then H2O to balance the hydrogens. Why do we not balance the oxygens with H2O and the hydrogens with H+ to produce an oxidation half reaction ...

Keirsten Andersen 3L

I understand what cis and trans molecules refer to but how did Dr Lavelle know that the second line structure on page 105 of our course reader is trans just by looking at it? I have drawn the Lewis structure and am still unsure.

Keirsten Andersen 3L

When finding the order of a reaction, if you write out the rate equation, can you just count the exponents to give the order?

Keirsten Andersen 3L

When comparing three experiments to determine the order of reaction, when do you compare 1 to 2 and 2 to 3 vs comparing 1 to 2 and 1 to 3, as the book does?

Keirsten Andersen 3L

Given the balanced equation above we can tell the Au + (aq) going to Au 3+ (aq) is being oxidized because the charge is increase because it is losing electrons. Thus, this is the anode. The Au + (aq) going to Au(s) is being reduced because the charge is reducing. Thus this is the cathode. When writi...

Keirsten Andersen 3L

You have to break that into two reactions Au + (aq) goes to Au(s) Au + (aq) goes to Au 3+ (aq) from there add electrons as needed so the charge of both sides of each reaction is equal. This will look like 2e - plus 2Au + (aq) goes to 2Au(s) Au + (aq) goes to Au 3+ (aq) plus 2e - add these together t...

Keirsten Andersen 3L

Do the placement of double bonds effect degeneracy? For example, does benzine have a W of 1 or 2?

Keirsten Andersen 3L

Yes, the increments between degrees Celcius and Kelvin are the same. Ex: 1 degree C = 274 K and 2 degrees C = 275 K

Keirsten Andersen 3L

If you are not given any values of temperature or heat and the products and reactants are in the same state (ex: Practice Quiz 1 winter 2014 number 8), how do you know if the change in entropy is positive or negative? In this example, Cl2 gas becomes 2 Cl gas.

Keirsten Andersen 3L

What are the differences between extensive and intensive properties and what are their implications in chemistry?

Keirsten Andersen 3L

I understand the concept behind reversible reactions, but what exactly defines an irreversible reaction?

Keirsten Andersen 3L

On page 6 or 21 of our course reader it states "molar heat capacity, J per degree K per mole" and right underneath says "heat required to raise temp of 1 mole of a substance by 1 degree C." So I am confused as to weather molar heat capacity is measured in degrees K or degrees C. ...

Keirsten Andersen 3L

Wouldn't the motion of the stir-er in a calorimeter increase the temperature of the water that is being used to measure the temperature increase upon combustion?

Keirsten Andersen 3L

Why can't Cl have an expanded octet? Our book states "nonmetal atoms in Period 3 or later periods can expand their valence shells," and Cl is a non metal in period 3.

Keirsten Andersen 3L

When drawing a lewis structure, is there a method to decide which element will receive the formal charge? For example, if I can arrange electrons/ bonds to give either Cl or O a formal charge of 1-, how do I decide which way to draw it? For example when drawing SO2Cl-, you can either attach one O to...

Keirsten Andersen 3L

Why is it correct to draw the lewis structure of SO2 with a 1+ charge on the S and a 1- charge on an O? Why wouldn't you use two double bonds to attach each O to the central S resulting in no formal charge anywhere?

Keirsten Andersen 3L

What is the definition of a neutralization reaction? How do CH3COOH and NaOH neutralize each other? Specifically, how to we figure out the moles of CH3COOH and CH3COO- after neutralization?

Keirsten Andersen 3L

How can you tell a compound is a salt? What factors make KBr a salt, for example?

Keirsten Andersen 3L

What is the difference between Bronsted and Lewis acids and bases? How do you choose which label to primarily call a compound?

Keirsten Andersen 3L

Is C10H16N2O8 correct?

Keirsten Andersen 3L

What is the formula for ethylenediaminetetraacetato? The textbook only includes a diagram.

Keirsten Andersen 3L

In homework problem 17.29, problem a and c include the ligands CN. Since there is no negative subscript after CN, how are we supposed to know they are implying it's the CN ion?

Keirsten Andersen 3L

Another way to determine hybridization is to simply count the regions of high electron density (lone pairs and bonds) and then build your hybridization from lowest energy (s subshell) to highest (g subshell). So for benzine, each carbon has three bonds (one to the hydrogen and two to the adjacent ca...

Keirsten Andersen 3L

Is there a way to determine if a reaction is in equilibrium if you are not given the K value?

Keirsten Andersen 3L

When identifying the composition of sigma and pi bonds does it matter which element we list first in the parenthesis? For example, are are sigma(C2sp^2, O2sp^2) and sigma (O2sp^2, and C2sp^2) interchangeable or do they mean different things?

Keirsten Andersen 3L

When drawing a Lewis Structure for an ionic compound, O2^2- for example, is it better for one atom to have a formal charge of 2- or both atoms to have a formal charge of 1- to produce an overall charge of 2-?

Keirsten Andersen 3L

Are all elements in groups 6 and 11 of the d-block of the periodic table exceptions when writing electron configurations like Chromium and Copper are? Since they all have full d5 and d10 subshells I feel like this is logical but have been taught that only Cr and Cu are exceptions.

Keirsten Andersen 3L

How do we know which of the many values of m when l>0 are correct? For example, for l=3, m= [-3, -2, -1, 0, 1, 2, 3]. Which of these seven numbers is accurate and tells us the orientation?

Keirsten Andersen 3L

What exactly is rest mass and how do we know that photons, for example, have no rest mass?

Keirsten Andersen 3L

The back of our text book has a very helpful list of SI prefixes. For example, nano- is 10^-9. Thus, a nanometer is equal to 1 x 10^-9 meter. Knowing this, you can cross multiply the value you found (3.4 x 10^-7 m) with the conversion factor of 1 nm per 1 x 10^-9 m to reach 340 nm.

CHEMISTRY COMMUNITY

Search found 33 matches

Winter 2014 Final Q1C vaporization term

Winter 2013 Final Q6A, naming

Winter 2013 Final Q4C reaction rate

Winter 2011 Final Q3A

Cis and trans in line structures

Finding order

Comparing experiments to find order rxn

Re: electrochemistry ch question 13.d

Re: electrochemistry ch question 13.d

Determining degeneracy

Re: Units of molar capacity

Finding change in entropy with no numbers

Extensive v Intensive Properties

Reversible v Irreversible Reactions

Units of molar capacity

Stirer increasing heat in calorimeter

Re: Determining which element to give a formal charge

Determining which element to give a formal charge

Lewis Structure of SO2

2010 Final Q7B neutralization reaction

Determining if a compound is a salt

Bronsted vs Lewis acids and bases

Re: Formula of ethylenediaminetetraacetato

Formula of ethylenediaminetetraacetato

Implied Ion Ligand. Homework 17.29

Re: How do you find hybridization?

Determining if a reaction is in equilibrium

Fall 2010 Midterm Q6: Identifying composition of bonds

FC when drawing Lewis Structures on ionic compounds

Exceptions in electron configuration

Oribitals, value of m

Rest Mass

Re: How do you go from meter to nanometer? [ENDORSED]