CHEMISTRY COMMUNITY

Noh_Jasmine_1J

the slow step usually has the same rate as the observed rate

Noh_Jasmine_1J

the reaction rate that matches the experimental rate is the slow step.

Noh_Jasmine_1J

if a catalyst affects the rate constant and rate constants of forward and reverse reactions can be used to find equilibrium constant then why does the catalyst not affect the equilibrium constant?

Noh_Jasmine_1J

what is the overall reaction rate used for?

Noh_Jasmine_1J

you can find that by adding all the individual reaction orders together

Noh_Jasmine_1J

what are the different ways that we can calculate reaction rates?

Noh_Jasmine_1J

how can you tell that Br2(l)-->Br^-(aq) is a reduction? what would the oxidation numbers be?

Noh_Jasmine_1J

what is the difference between oxidized and oxidizing agent?

Noh_Jasmine_1J

why do we balance H with H2O in basic rxns instead of just OH to begin with?

Noh_Jasmine_1J

when do we want to use the Van't Hoff equation?

Noh_Jasmine_1J

delta H and delta S should be consistent values to use this equation

Noh_Jasmine_1J

do you balance redox rxns by oxidation number or stoichiometry?

Noh_Jasmine_1J

Cp is for constant pressure and can be used in solving for q or delta S.
Cv is for constant volume in the same equations

Noh_Jasmine_1J

do you use 3/2R and 5/2R when calculating change in entropy when there is a temperature change? are there any other situations where you would use them?

Noh_Jasmine_1J

do you only use gases when solving with bond enthalpies or can you use solids and liquids as well?

Noh_Jasmine_1J

I thought when we calculated for ΔH, the equation used was ΔH=nCΔT, but in some calculations they don't use ΔT. Why is that?

Noh_Jasmine_1J

isothermal means that the temperature stays the same and I believe that is the right equation to use when solving those types of problems

Noh_Jasmine_1J

for 4.15 in the 7th edition book, the balanced chemical equation is 2HCl(aq)+Zn(s)--->H2(g)+ZnCl2(aq) and it tells you that a piece of zinc metal of mass 8.5 g is dropped into an apparatus containing 800.0ml of 0.5M HCl(aq). If the initial temp of the HCl acid solution is 25C, what is the final temp...

Noh_Jasmine_1J

what does the degree symbol mean in the equation ΔU°=ΔH°+W

Noh_Jasmine_1J

Units for work is in Joules and 1J is equal to kg*m^2*s^-2

Noh_Jasmine_1J

is the value for R in the equation w=-nRTln(V2/V1) always the same?

Noh_Jasmine_1J

how do I figure out how to determine the change in volume when I am solving for work done? the question asks to solve for the work of a pump in compression with a diameter of 3cm and the pump is depressed 20cm with a pressure of 2atm. thank you~

Noh_Jasmine_1J

what is the difference between pH and pKa? how would you solve for pKa if given pH?

Noh_Jasmine_1J

for gases in ICE table, do we still use concentration (mol/l) or use bar?

Noh_Jasmine_1J

if you're calculating with salts, how do you know what part of the equation you don't need to add in finding out values for K or Q?

Noh_Jasmine_1J

I know that you can figure out which way the rxn will favor if you know whether it's endothermic or exothermic, but how can you figure that out?

Noh_Jasmine_1J

I don't understand how to do part (b) of 6B.3 in the 7th edition with the 200ml value and 250ml value

Noh_Jasmine_1J

Do you have to figure out which direction the reaction goes before doing ICE table?

Noh_Jasmine_1J

In ICE charts can you fill in the chart with different units of measurement? Ex moles, mol/L, grams

Noh_Jasmine_1J

Noh_Jasmine_1G wrote:when do you use this equation?

forgot to write the equation haha. its the partial pressure equation

Noh_Jasmine_1J

when solving for the equilibrium constant using gases, can you use either mol/L or in bar?

Noh_Jasmine_1J

what is the difference between [Cl2] vs (PCl2) and what does the brackets mean compared to the parenthesis with P in them?

Noh_Jasmine_1J

when do you use this equation?

Noh_Jasmine_1J

Why is formic acid a stronger acid than acetic acid? Formic acid has a -CH3 group and acetic acid is HCOOH.

Noh_Jasmine_1J

How do you write the chemical formula for coordinations compounds? Are they alphabetical?

Noh_Jasmine_1J

How can you tell if something is polydentate or not? Are you always given a drawing or do you have to figure it out by the chemical formula?

Noh_Jasmine_1J

can someone explain what acidic, basic, and amphoteric oxides are? I didn't understand the book's definition of it

Noh_Jasmine_1J

if a hybrid orbital is created, does that mean there is only one electron per energy level?

Noh_Jasmine_1J

How do you know if one of the orbitals is hybridized or not?

Noh_Jasmine_1J

sigma bonds are located on the axis and so they are able to rotate around it, but pi bonds are located above and below the axis and therefore cannot rotate

Noh_Jasmine_1J

for the names of the different shapes, is the only way to learn them is to memorize the names of the shapes that correspond to the AXE form?

Noh_Jasmine_1J

for SO2Cl2, do the 2 oxygens and 2 chlorines have to be next to each other around the sulfur or can they be directly across from each other?

Noh_Jasmine_1J

how can you tell the type of bond (pi or sigma) with knowing the hybridization?

Noh_Jasmine_1J

Lone pairs have greater repulsion than bonds and therefore cause the bond angles to be smaller than expected

Noh_Jasmine_1J

does electron density only refer to the central atom? and is the electron density around the central atom the only one we use to determine molecular shape?

Noh_Jasmine_1J

do we just have to memorize the bond angles for different molecular shapes?

Noh_Jasmine_1J

usually the distance between the 2 atoms will be useful. if they are further apart that means they will have greater ionic character because the electronegativity is greater

Noh_Jasmine_1J

why does oxygen usually have the negative formal charge in a lewis structure compared to carbon?

Noh_Jasmine_1J

why does Oxygen have lower ionization energy than Nitrogen ?

Noh_Jasmine_1J

why are the electron affinities for Be and Mg the same when Mg is below Be? I thought electron affinity increases as you go right and up

Noh_Jasmine_1J

why does electronegativity, electron affinity, and ionization energy all increase to the right?

Noh_Jasmine_1J

hi, how do I determine the central atom of a lewis structure?

Noh_Jasmine_1J

why does lower energy mean that an atom is more stable?

Noh_Jasmine_1J

how do you know to draw two separate lewis structures for ammonium sulfate and just one for glycine (H2O(NH2)COOH)?

Noh_Jasmine_1J

Hi, I am confused on when to use the equation λ=h/p vs λ=hc/E or if they are interchangeable. thank you so much !

Noh_Jasmine_1J

hi, i'm confused on what shielding does to the s, p, d, and f orbitals. I know that p has greater energy than s but is this talking about the electrons energy being closer to zero? also how does all of this relate to the equation: E is proportionate to (q1)(q2)/r ?

Noh_Jasmine_1J

Hi, could someone clarify the characteristics that make an electron act like both a particle and wave?

Noh_Jasmine_1J

Hi, I am confused on how we make the connection between the Schrodinger Equation and the determination of atomic orbitals. Could someone explain it to me?

Noh_Jasmine_1J

angelagd3l wrote:what units are we using while working with wavelengths?

wavelengths are usually given in meters but usually you can switch it by a power of 10 to make nanometers, picometers, etc to make the number friendlier

Noh_Jasmine_1J

Tamera Scott 3L wrote:I've also seen E=hf once, does anyone know if that is the same as E=hv?

v is the symbol for frequency, so both equations are equivalent

Noh_Jasmine_1J

I'm not completely sure but I think that the energy per atom can be found at the back of the textbook for the referencing during homework and should be given for a test.

Noh_Jasmine_1J

This is just showing the ratio of the Fe to the compound for that specific chemical reaction. The molar ratio could be different for other reactions

Noh_Jasmine_1J

You can solve for the molar mass if the question gives you the chemical formula because there is a periodic table given for the test

Noh_Jasmine_1J

I usually start with the one that appears the least (usually only once) because then I don't have to search around and make sure I'm adding all the moles correctly. After starting with the least, I see which numbers would be easiest to match and go from there

Noh_Jasmine_1J

In multiplying and dividing you always use the smallest number of sig figs between those two numbers and in adding and subtracting you should use the smallest number after the decimal point. For example: 1.23 + 1.5 would be 2 sig figs because there is only one number after the decimal point in 1.5

Noh_Jasmine_1J

hi, I can confused on when to use subscripts for certain elements on the periodic table. For example, I don't know understand why chlorine gas is written as Cl2 instead of just Cl (M.15)

Noh_Jasmine_1J

hi, I just had a question for M.9, which asks for us to write the net ionic equation for the reaction: copper(II) nitrate reacts with sodium hydroxide to produce a precipitate of light blue copper(II) hydroxide. what do the Roman numerals mean and how does NaNO3 appear on the products side out of no...

Noh_Jasmine_1J

Hi. I have a question regarding this problem as well: why is the oxygen written as "O" without the subscript 2 until the formula is written? I though oxygen was always O2

Noh_Jasmine_1J

Hi I have a question on E.15 (7th edition). It gives me the molar mass of a metal oxide M(OH)2 as 74.10 g/mol and asks me to find the molar mass of the sulfide. How do I make the connection between sulfide and (OH)2?

Noh_Jasmine_1J

Update: I realized that the astatine atoms weren't on the pan and figured it out!

Noh_Jasmine_1J

Referring to question E.3, how do you know to increase astatine atoms by 3? It gives you 9 gallium atoms (molar mass 70 g/mol) and 9 astatine atoms (molar mass 210 g/mol) and asks how many astatine atoms are needed to make the masses equal.

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