CHEMISTRY COMMUNITY

Marsenne Cabral 1A

When finding the rate law, when is it ok to approximate a number to a whole one?

Marsenne Cabral 1A

I think a way to do this is put in hypothetical concentrations for each number and see what exponent makes the rate double for each situation.

Marsenne Cabral 1A

In what context is the nFE equation negative/positive?(like for free energy vs E)

Marsenne Cabral 1A

why would the neutral ph change from 7 in a chemical reaction and how is that possible?

Marsenne Cabral 1A

What would an example of a chemical reaction equation of a zero order reaction?

Marsenne Cabral 1A

I am still confused though, is the trans isomer only looking at the molecules 180 degrees apart?

Marsenne Cabral 1A

If you are just given E for the half reactions is there any way to tell which one is the cathode and which one is the anode?

Marsenne Cabral 1A

How do we use use faradays constant in the equation for Gibbs free energy?

Marsenne Cabral 1A

When calculating the change in Gibbs free energy of the formation of a compound, is the temperature just at 25 degrees Celsius?

Marsenne Cabral 1A

Why is the delta G for a spontaneous process negative always?

Marsenne Cabral 1A

What happens when there is zero Gibbs free energy? Like when K=1 and R and P are in their standard state?

Marsenne Cabral 1A

Can somene help me understand what we use the ln(K2/K1)=-(deltaH/R)[1/T2-1/T1] equation?

Marsenne Cabral 1A

Even if the reaction you have is irreversible, do you still use change in entropy= qrev/T?

Marsenne Cabral 1A

When would you use the -nRTln(P1/P2) equation?

Marsenne Cabral 1A

Are there any restrictions on when you can use delta nRT in place of PdeltaV?

Marsenne Cabral 1A

Can anyone help me with this question?

How much work does 100 g of water do when it freezes at ) degrees Celsius and pushes back the metal wall of a pipe that exerts an opposing pressure of 1070 atm? The densities of water and ice at 0 degrees Celsius are 1.00g/cm^3 and .92 g/cm^3 respectively.

Marsenne Cabral 1A

When a reaction goes from a solid to a liquid, why does delta H equal delta U?

Marsenne Cabral 1A

Why is the enthalpy of bonds (delta H b) always greater than zero and endothermic?

Marsenne Cabral 1A

What is the difference between Delta H and T? Today in Lecture Lavelle said that an increase in T would mean the reaction is exothermic, and that would mean that the delta H is negative, so how would that work?

Marsenne Cabral 1A

Can someone help me clear up the difference between reversible and irreversible reactions and the difference in work?

Marsenne Cabral 1A

For the equation Ni(CO4)<->Ni + 4CO, where x is the equilibrium concentration of CO, how would you put the equation in terms of X. The answer says that it would be x*4/(1.0-x/4) but how would you get the top to be x^4 ?

Marsenne Cabral 1A

I got .05 grams for number 2 on the acid base worksheet because I first found the hydronium concentration then I solved for X and from there multiplied the answer by the molar mass, and did not get .1. Can anyone help me on this?

Marsenne Cabral 1A

Will we ever have to calculate the pH of a week acid/ base where the stoiciometric constant is not one, if so, are there any example and how would you go about solving the problem?

Marsenne Cabral 1A

Are there any exceptions to the rule about salts/elements that do not change ph? Are all group 1 and 2 cations and, H, Br, and I the only elements that do not affect pH?

Marsenne Cabral 1A

In class today Lavelle said that if you have a very small amount of a very weak acid, that changes the answer you get because if the concentration of H30+ is 10^-7 and you get the concentration at the end to be 10^-9, you have to do something different to get the correct answer? What would that be?

Marsenne Cabral 1A

When calculating concentrations and the stoichiometric coefficients are not one, how would one account for that? Would you square the concentrations of multiply them by the coefficients?

Marsenne Cabral 1A

When Looking at the flasks in question 11.7 in the 6th edition, the answer says that the third flask is in equilibrium, but I am wondering why because the third and fourth flasks both have the same number of dissociated and non-dissociated molecules? Can anyone help me with this question? The questi...

Marsenne Cabral 1A

When calculation concentration in mol.m^-3, and you are given R in m^3 how would you do the conversions?

Marsenne Cabral 1A

When trying to find the pH of a solution that has both an acid and a base in it, would it just be the negative log of the molarity of the acid? Do you need to take into account the molarity of the base too?

Marsenne Cabral 1A

How would you write out Bisethylenediaminediiodomanganese(IV) ion?

Marsenne Cabral 1A

How would you tell the coordination number of a heme? Is the coordination number the same thing as looking to how many bonds are to the central atom? If so, how does the coordination number relate to what kind of chelate it is?

Marsenne Cabral 1A

Can someone give me an example of a dipole-induced dipole molecule? I just need some help clarifying what they look like and how the charges affect each other.

Marsenne Cabral 1A

What do sigma bonds look like on an orbital?

Marsenne Cabral 1A

When determining which cation/anion has more polarizing power/polarizability, which weighs more, charge or placement on the periodic table?

Marsenne Cabral 1A

How come atoms like Boron and Aluminum are exceptions to the octet rule? Is there an easy way to remember exceptions?

Marsenne Cabral 1A

Can someone help me draw the N5+ Lewis Structure? I cannot figure it out.

Marsenne Cabral 1A

When forming double and triple bonds, there is only one sigma bond, is there a reason why its only possible to form one sigma bond in double and triple bonds?

Marsenne Cabral 1A

What is an example of when pi bods break in the natural world if there are any?

Marsenne Cabral 1A

Can someone help explain how the see saw shape comes about and why the 90 degree angles are more stable?

Marsenne Cabral 1A

What is the VSEPR notation for a molecule with an octahedral shape?

Marsenne Cabral 1A

I understand how sigma bonds allow for rotation and pi bonds do not, but could someone help me figure out how in class today, he said that a triple bond between two N atoms would have one sigma bond and two pi bonds?

Marsenne Cabral 1A

Can anyone explain more about dipole-induced dipole? I understand how it is a dipole with an atom that does not form one, and then the dipole causes the other atom to become a dipole, but could someone explain to me how this happens?

Marsenne Cabral 1A

Will we ever have to find exact bond length? Or do we just need to know trends and how they all average?

Marsenne Cabral 1A

Are all molecules with four bonding pairs tetrahedral? What makes the difference if they are not?

Marsenne Cabral 1A

Can someone help clear up how to find different bond lengths in an atom?

Marsenne Cabral 1A

What is the Lewis Structure of ethanol: CH3CH2OH?

Marsenne Cabral 1A

Can someone help me draw the lewis structure for potassium phosphide?

Marsenne Cabral 1A

When an atom of an element does not have an octet, is there a specific side that the unpaired electrons (dots) should be drawn on? Or does it matter?

Marsenne Cabral 1A

Can anyone help explain why some electrons are not paired in orbitals even if there are an even number of electrons? I am still a little bit confused.

Marsenne Cabral 1A

Is there any surface that would emit electrons when the light being shown on it is visible light?

Marsenne Cabral 1A

I believe he was talking about how the wave function of an electron looks like the sin function and if you take the double derivative you get -sin so that corresponds to how the hamiltonian (H in the equation) ends up equaling the energy of the electron (E) when you multiply both by psi? Can someone...

Marsenne Cabral 1A

Is an angular node the same thing as a nodal plane?

Marsenne Cabral 1A

Can someone help clear up if the atomic radius gets bigger when electrons move from the s orbital to either the p,d,or f orbitals? I think the radius stays the same but just want clarification?

Marsenne Cabral 1A

Is the negative symbol in front of the equation just a symbol that there is an energy decrease, and the actual energy of each level is still positive, or is there another explanation?

Marsenne Cabral 1A

This is confusing terminology to me too, but I believe spectrum emission is when the actual line shows up and spectrum absorption is where all colors are absorbed so there is no line, but I am not sure either. Can someone help clear this up?

Marsenne Cabral 1A

When calculating the mass of an electron, why is the SI unit in kg and not grams? Wouldn't grams make more sense?

Marsenne Cabral 1A

I am also confused as to how to go about this problem. It seems to me that it is a dilution equation followed by a limiting reactant equation but I am confused as to how to do the limiting reactant problem when it is a solution. Can anyone help?

Marsenne Cabral 1A

I understand that even when gram amounts for different reactants differ, it is not automatically the smallest one that becomes the limiting reactant, but what is the reason that that is the case?

Marsenne Cabral 1A

When trying to find the individual molar mass of ions in a chemical formula, would we first calculate the mass percentage that the ions have in the formula and then calculate the molar mass?

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