CHEMISTRY COMMUNITY

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I find it much simpler to do Ecathode-Eanode instead of reversing cell potentials.

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You can find n easily after balancing the redox reaction.

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N is 2 because 1 electron is being added to Ce, but there are two moles of it so you multiply the number of electrons added/removed by the number of moles of the reduced/oxidized compound.

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I find it more straightforward to do Ecathode- Eanode rather than reversing Ecell because sometimes the reduction potential is negative and it can get confusing.

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Since each of them have their own phase change, you use that phase's specific heat capacity.

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Using the vant hoff equation can help you see how temperature affects K. From there you can determine if a certain pH is neutral.

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To add, using the arrhenius equation to solve for pre-exponential factor, A, gives you insight into the frequency of collisions that are in the correct orientation.

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You should also know that a catalyst doesn't appear in the overall reaction.

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You can tell if a reaction is likely to occur through the sign of delta G or Epotential.

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What is the difference between adiabatic and isochoric?

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When you have a reaction that is not first order and you want to determine one of the reactant's concentration, you can use a pseudo-first-order reaction in which one of the reactants is in great excess, essentially remaining constant as the reaction progresses. This allows you to determine concentr...

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To add, half-life is important to determine how quickly quickly unstable atoms undergo, or how long stable atoms survive, radioactive decay.

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Half life is the time that it takes for a substance to decompose into half of its intial state, no matter the state.

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I think that you should always get a linear plot for 0,1,and 2 order reactions!

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I don't believe that one is more efficient than the other.

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Thank you!

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You should usually stick to using either concentration or partial pressures when calculating Q

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Will we be expected to know how to calculate the standard potential of a couple
from two related couples on test 2?

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Pressure can sometimes be given in Pascals or kilopascals as well.

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It helps to think of this in terms of k in an equilibrium equation to determine whether it will proceed to reactants vs products.

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When deltaG is positive the reactants are more thermodynamically stable, so the reaction proceeds to the left.
When deltaG is negative the products are more thermodynamically stable, so the reaction proceeds to the right.

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Using "standard" simply indicates that the substances in question are in standard state.

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Yes, free energy is a state function

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To add, when the equation is derived, delta g is assumed to be zero since the system is at equilibrium

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To add, delta H can also equal w if the temperature of the system is not changing because delta h = q+w and q would then be zero.

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You can also cross out bonds if both the products and reactants both have the same number!

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When a structure has resonance and you are calculating the enthalpy for its formation, how do you know whether to use the bond formation enthalpy for its single, double, or triple bonds?

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open: bowl of hot soup
closed: a sealed bag of fruit
isolated: an insulated coffee mug

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since in a cup of tea will cool down over time, it will exchange energy with surroundings. since a cup is typically not covered on the top, tea could also leave the system . since both matter and energy can be exhanged, then a cup of tea is an open system

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an insulated water bottle would keep temperature (energy) constant and if it is closed then no water will leave. this means that no matter or energy is exchanged, the qualifications for an isolated system

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pH is a measure of the amount of free hydrogen and hydroxyl ions in the water. Water that has more H+ ions is acidic, but water that has more OH- ions is basic. pH is affected by chemicals in the water, so it can be indicative of chemical changes happening in water.

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You can typically disregard elements that don't affect the pH/pOH.

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Phase changes like freezing, however release energy into the surroundings so it can be considered exothermic.

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I think the directions should tell you to balance it first.

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How is a salt formed?

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You can compare the strength of two acids by comparing their acidity constants. small Ka values correspond to weak acids.

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AlCl3 can act as an acid because it accepts electrons.

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You can typically assume that the value of x is negligible when the Ka or Kb is less that 10^-3. If it's not, then you should always include x in your calculations.

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You should repeat the same process of finding pH, but instead use the actual volume used, which was 250 mL.

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