CHEMISTRY COMMUNITY

Jaewoo Jo 2L

It depends on the power of the components in the rate law. if one component is a squared, then the rate will change by a factor of 4.

Jaewoo Jo 2L

yeah, the first 2 terms are for gibbs and the later 2 are for heat.

Jaewoo Jo 2L

It's the one that donates the electron.

Jaewoo Jo 2L

the second is just rearranged with log rules, so it's the same thing

Jaewoo Jo 2L

your units just have to be consistent, unless the questions state otherwise.

Jaewoo Jo 2L

k is equal to k/k'

Jaewoo Jo 2L

I think it just allows us to measure the initial rate of a reaction if we have a limited amount of reactants or if the reaction happens really fast (like faster than the human eye can see).

Jaewoo Jo 2L

I leave it at seconds unless it is stipulated that minutes or any other time measurement is used instead.

Jaewoo Jo 2L

You need to find the K with the right units so that it cancels with the rate order equation.

Jaewoo Jo 2L

The order does not matter if the order is switched but can't switch over between reactants and products.

Jaewoo Jo 2L

If it's a halogen or H2 (stable elements) and it's are diatomic, it still has an oxidation number of zero.

Jaewoo Jo 2L

Yes, you multiply by the least common multiple so you can get the electrons to cancel on both sides.

Jaewoo Jo 2L

delta U would also be zero in an isolated system or any system that doesn't transfer heat.

Jaewoo Jo 2L

The human body is also a good example of a open system because heat is transferred between surroundings (heat regulated by sweating or shivering) to keep equilibrium, and we eat food (put matter into the system) to gain energy.

Jaewoo Jo 2L

I think until now, we've mostly seen the R values with atm or joules, and like what everyone said above, you just use the value with the units that cancel with corresponding units in your calculations.

Jaewoo Jo 2L

More heat is released at constant pressure because the volume gets smaller as well as the temp getting lower, requiring extra work. if the volume is constant, than only the temperature is going down, releasing less heat.

Jaewoo Jo 2L

I guess like the example seen on the practice midterm from the review session today, some questions will explicitly state that calculating a phase change is not required, while others will state that you are going from liquid to gas which implies that you need to include the phase change (although t...

Jaewoo Jo 2L

If the system is the reaction and the surrounding is the beaker, there isn't a word left for everything else. if the reaction is the system, then the beaker and the atmosphere is the surroundings.

Jaewoo Jo 2L

this is like the question in the quiz where petrol was burned in an isolated chamber. the combustion reaction generated heat but the heat didn't escape from the system or enter from the surroundings.

Jaewoo Jo 2L

like the replys above, density, atmoic structure, temperature, the states of the elements all come into play and it would be almost impossible to classify them into trends in the periodic table.

Jaewoo Jo 2L

like the reply above, I've only ever seen the same elements being used, but there is no reason carbon and platinum wouldnt work.

Jaewoo Jo 2L

the universe is an isolated system as the universe in itself is a system with no surroundings. With the first law of thermodynamics, no energy in the universe can be created or destroyed, so the universe is an isolated system.

Jaewoo Jo 2L

yeah, i think the ideal cooler means that there is no heat transfer between the system and the surroundings.

Jaewoo Jo 2L

since work is force x distance, doing anything that requires a certain force to move something a certain distance (like push-starting a car) is work being done.

Jaewoo Jo 2L

deltaU= change in internal energy. Internal energy is the energy in every molecule of in the substance. deltaU = Q+W Q= heat added to system and W= work done on the system deltaU+PdV= W change in enthalpy (deltaH) is change in total energy of the system and enthalpy H can be written as H= U+PV delH=...

Jaewoo Jo 2L

that's because the w = -delta(nRT) equation only works when it's a gas because liquids and solids do not expand or change.

Jaewoo Jo 2L

Yeah, in the question the lower bond energies = the lower molar energies. the 3 C-C bonds and C(double bond)C bonds has the value 2880kJ and the 6 resonance-stabilized bonds has 3108kJ so 3108kJ is more stable by 228kJ, as it takes that much more energy.

Jaewoo Jo 2L

the question would tell you that the reaction is hypothetically reversible and irreversible so we need to solve for both and compare how much energy was used or released. Also, this is relevant because the irreversible reaction requires or releases less energy than reversible ones.

Jaewoo Jo 2L

Internal energy increased more than the amount of heat added, so the extra energy is from the work done to the system. Since the equation to calculate work is "w= deltaU-q", plug in the values of change in internal energy and heat absorbed given in question to get "982 J - 492 J = +4....

Jaewoo Jo 2L

Yes, It should always be applicable.

Jaewoo Jo 2L

Basically, if we're talking about water, heat capacity is just the energy required to raise water by 1 degree. Specific heat is the energy required to raise water of some mass by 1 degree. So the relationship would be heat capacity = specific heat * mass. The heat capacity of water would be differen...

CHEMISTRY COMMUNITY

Search found 31 matches

Re: rate proportions

Re: Vocabulary

Re: nucleophiles

Re: Equation variations

Re: Units

Re: Equilibrium constant

Re: Stopped Flow Technique

Re: Units

Re: k units [ENDORSED]

Re: Does order matter?

Re: Oxidation state

Re: Balancing number of electrons

Re: First Law

Re: Open System

Re: What does R stand for?

Re: 8.31

Re: calculating a phase change in a reaction

Re: system vs surroundings

Re: Isolated

Re: Periodic Trends

Re: Solids [ENDORSED]

Re: Open, closed, or isolated [ENDORSED]

Re: ideal cooler [ENDORSED]

Re: Examples of work being done

Re: ΔU vs. ΔH

Re: 8.93 part b

Re: 8.77

Re: Reversible and Irreversible

Re: Question about Question 8.7

Re: work equation

Re: Specific Heat Capacity vs Heat Capacity