CHEMISTRY COMMUNITY

Ashley Macabasco 2K

In K=k/k', K refers to the equilibrium constant which can also be found by [products]/[reactants]. For the reaction A+B-->C+D k = rate/[A][B] and k' = rate/[C][D]. k/k' would then equal (rate/[A][B])([C][D]/rate) where the rates would cancel leaving [C][D]/[A][B] or [products]/[reactants].

Ashley Macabasco 2K

In an acidic solution potassium permanganate and iron(II) chloride will dissociate into K+ ions and permanganate and Cl- ions and iron respectively. Because these ions dissociate they are not included in the half-reactions.

Ashley Macabasco 2K

I believe that the first equation q = (Cv)(delta T) stems from the equation q=n(C)(deltaT T). The first equation does not include mole because the C value given is in terms of kj/C and so I believe that you can assume that the moles were already taken into account. I am unsure of where the second eq...

Ashley Macabasco 2K

I believe you must only convert mmol to mol or vice versa if the question explicitly states to do so.

Ashley Macabasco 2K

Intermediates are formed in one step and the consumed in the next, so the intermediate will be the species that is present in the steps but not present in the final equation.

Ashley Macabasco 2K

From my knowledge and the homework problems, k seems to be the same throughout experimental data regardless of the concentrations.

Ashley Macabasco 2K

It does not matter what coefficient you use as long as the electrons cancel out in the end because you can always simplify the equations.

Ashley Macabasco 2K

Usually the oxidation (anode) is written on the left and the reduction (cathode) is written on the right. This can be remembered by R in reduction also standing for right.

Ashley Macabasco 2K

Because R, T and F are constants at standard conditions, the second equation is the same as the first equation with the constants computed into a single constant.

Ashley Macabasco 2K

Regardless of if the compounds are on the oxidation or reduction side, each compound in a different phase will be separated.

Ashley Macabasco 2K

If E(cathode)>E(anode) then K>1 and products are favored.

Ashley Macabasco 2K

From what I have seen the aqueous compounds are written closest to the middle, the closest to the salt bridge and then the solids are farthest compounds from the salt bridge. Liquids and gases are then written in between.

Ashley Macabasco 2K

For a reversible system, delta S total would equal zero.

Ashley Macabasco 2K

An oxidizing agent gains electrons which can be seen through a half-reaction. The reducing agent then loses electrons.

Ashley Macabasco 2K

Justin Folk 3I wrote:I thought we can only measure change in entropy?

Positional entropy does not measure the change in entropy, but the entropy possible through the number of particles and the position of such particles in the formula S = klnW.

Ashley Macabasco 2K

You should always use a + or - sign when doing change calculations to determine whether something is being lost or gained through a reaction.

Ashley Macabasco 2K

From my understanding, internal energy is found by the work and heat of a system so even if temperature is constant, the internal energy can change with the amount of work done.

Ashley Macabasco 2K

I would suggest knowing how to use the equations and how to derive them. Though we may not be asked on an exam how to derive a equation, understanding where an equation comes from will help you know how and when to use it.

Ashley Macabasco 2K

Residual entropy is a specific type of entropy and is the same as positional entropy in which the entropy is based upon the arrangement of molecules or atoms.

Ashley Macabasco 2K

Degeneracy (w) is used to calculate statistical entropy and refers to the number of combinations atoms or molecules can be in and create energy. Statistical entropy is therefore dependent on w as it shows the different ways positional entropy can occur.

Ashley Macabasco 2K

The change in pressure equation is P1/P2 opposed to P2/P1 like for the change in temperature and the change in volume because of Boyle's law in which volume and pressure are inversely proportional.

Ashley Macabasco 2K

The temperature change could be calculated either way using Kelvin or Celsius because regardless of which unit you use, the difference between the two temperatures will be the same.

Ashley Macabasco 2K

Cv is used when a reaction is occurring at a constant volume and Cp is used when a reaction is occurring at a constant pressure.

Ashley Macabasco 2K

The term "ideal behavior" simply means that the gas is acting like an ideal gas and would follow the ideal gas equations (PV=nRT).

Ashley Macabasco 2K

Mercury in a thermometer is an example of a closed system because the mercury itself is unable to leave the thermometer, but its energy is able to be exchanged with its surroundings (energy seen as heat). The transfer of heat is what makes the mercury leave in a thermometer rise or drop with heat ca...

Ashley Macabasco 2K

In the solution manual -q(water)=q(ice) illustrates that heat from water is being transferred exothermically to the ice shown with the lose of heat (-q). The ice is then gaining heat endothermically from the water which can also be seen with q being positive for ice.

Ashley Macabasco 2K

In the equation ΔU= q+w both q and w are positive to show that the change in internal energy consists of both the transfer of heat and the transfer of work in a closed system. Because the heat transfer may be negative (due to the system losing heat) or positive (due to the system gaining heat), q ca...

Ashley Macabasco 2K

I believe that 4 moles are broken in the C-H bond because there are four hydrogens bonded to one carbon in CH4 (lewis structure) so there are four C-H bonds and not one C-H bond. There are 4 moles of the H-Cl bond formed because of the 4 coefficient in "4 HCl" indicating that four H-Cl bon...

Ashley Macabasco 2K

For Hess's law, do you only add the enthalpy changes of the same phase to find the standard reaction enthalpy? For example in question 8.59 to calculate the standard reaction enthalpy of 4HNO3(l) + 5N2H4(l) ---> 7N2(g) + 12H2O(l), nitrogen is not included in finding the standard reaction enthalpy an...

Ashley Macabasco 2K

An ice cube melting is an endothermic reaction because the ice cube must take in heat in order to begin melting. It is endothermic because heat must go into the ice cube ("en"dothermic - "in"to the ice cube) instead of the ice cube emanate heat which would be an exothermic reacti...

CHEMISTRY COMMUNITY

Search found 30 matches

Re: k' reverse reaction constant

Re: 14.17?

Re: Delta Hc

Re: unit of concentration [ENDORSED]

Re: Intermediate [ENDORSED]

Re: to find k

Re: Balancing number of electrons

Re: Cell diagram order

Re: Cell Potential

Re: Cell Diagram [ENDORSED]

Re: 14.31

Re: Cell diagram

Re: reversible system

Re: Oxidizing vs. Reducing Agent

Re: s vs. delta s

Re: When to use + sign

Re: 8.101 (c) and (f)

Re: Derivation

Re: Residual Entropy

Re: entropy vs. Degeneracy

Re: Isothermal pressure change

Re: Question 8.31

Re: CV or CP

Re: Ideal Behavior

Re: HW #1 PART E

Re: Question about Problem 8.41

Re: the sign of q and w [ENDORSED]

Re: 8.73.b

8.59

Re: Endothermic Reaction