## Search found 31 matches

Sun Mar 18, 2018 11:00 pm
Forum: General Rate Laws
Topic: rate proportions
Replies: 2
Views: 467

### Re: rate proportions

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.
Sun Mar 18, 2018 10:58 pm
Forum: *Calculations Using ΔG° = -RT ln K
Topic: Vocabulary
Replies: 5
Views: 2566

### Re: Vocabulary

yeah, the first 2 terms are for gibbs and the later 2 are for heat.
Sun Mar 18, 2018 10:54 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: nucleophiles
Replies: 3
Views: 1178

### Re: nucleophiles

It's the one that donates the electron.
Mon Mar 12, 2018 12:00 am
Forum: First Order Reactions
Topic: Equation variations
Replies: 9
Views: 651

### Re: Equation variations

the second is just rearranged with log rules, so it's the same thing
Mon Mar 12, 2018 12:00 am
Forum: General Rate Laws
Topic: Units
Replies: 11
Views: 853

### Re: Units

your units just have to be consistent, unless the questions state otherwise.
Mon Mar 12, 2018 12:00 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Equilibrium constant
Replies: 3
Views: 420

### Re: Equilibrium constant

k is equal to k/k'
Sun Mar 04, 2018 11:04 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Stopped Flow Technique
Replies: 3
Views: 290

### Re: Stopped Flow Technique

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).
Sun Mar 04, 2018 10:59 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Units
Replies: 7
Views: 747

### Re: Units

I leave it at seconds unless it is stipulated that minutes or any other time measurement is used instead.
Sun Mar 04, 2018 10:57 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: k units [ENDORSED]
Replies: 7
Views: 611

### Re: k units[ENDORSED]

You need to find the K with the right units so that it cancels with the rate order equation.
Sun Feb 25, 2018 8:15 pm
Forum: Balancing Redox Reactions
Topic: Does order matter?
Replies: 7
Views: 454

### Re: Does order matter?

The order does not matter if the order is switched but can't switch over between reactants and products.
Sun Feb 25, 2018 8:12 pm
Forum: Balancing Redox Reactions
Topic: Oxidation state
Replies: 5
Views: 368

### Re: Oxidation state

If it's a halogen or H2 (stable elements) and it's are diatomic, it still has an oxidation number of zero.
Sun Feb 25, 2018 8:10 pm
Forum: Balancing Redox Reactions
Topic: Balancing number of electrons
Replies: 10
Views: 596

### Re: Balancing number of electrons

Yes, you multiply by the least common multiple so you can get the electrons to cancel on both sides.
Sun Feb 18, 2018 8:59 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: First Law
Replies: 5
Views: 681

### Re: First Law

delta U would also be zero in an isolated system or any system that doesn't transfer heat.
Sun Feb 18, 2018 8:55 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Open System
Replies: 5
Views: 546

### Re: Open System

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.
Sun Feb 18, 2018 8:51 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: What does R stand for?
Replies: 13
Views: 1402

### Re: What does R stand for?

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.
Sun Feb 11, 2018 9:34 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.31
Replies: 1
Views: 181

### Re: 8.31

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.
Sun Feb 11, 2018 9:25 pm
Forum: Phase Changes & Related Calculations
Topic: calculating a phase change in a reaction
Replies: 5
Views: 427

### Re: calculating a phase change in a reaction

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...
Sun Feb 11, 2018 1:40 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: system vs surroundings
Replies: 6
Views: 493

### Re: system vs surroundings

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.
Sun Feb 04, 2018 6:42 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated
Replies: 9
Views: 600

### Re: Isolated

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.
Sun Feb 04, 2018 6:35 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Periodic Trends
Replies: 4
Views: 336

### Re: Periodic Trends

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.
Sun Feb 04, 2018 6:28 pm
Forum: Balancing Redox Reactions
Topic: Solids [ENDORSED]
Replies: 2
Views: 267

### Re: Solids[ENDORSED]

like the reply above, I've only ever seen the same elements being used, but there is no reason carbon and platinum wouldnt work.
Mon Jan 29, 2018 1:29 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Open, closed, or isolated [ENDORSED]
Replies: 3
Views: 406

### Re: Open, closed, or isolated[ENDORSED]

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.
Mon Jan 29, 2018 1:26 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: ideal cooler [ENDORSED]
Replies: 5
Views: 370

### Re: ideal cooler[ENDORSED]

yeah, i think the ideal cooler means that there is no heat transfer between the system and the surroundings.
Sun Jan 28, 2018 12:35 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Examples of work being done
Replies: 7
Views: 541

### Re: Examples of work being done

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.
Sun Jan 21, 2018 11:46 pm
Forum: Phase Changes & Related Calculations
Topic: ΔU vs. ΔH
Replies: 10
Views: 1442

### Re: ΔU vs. ΔH

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=...
Sun Jan 21, 2018 11:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.93 part a
Replies: 1
Views: 136

### Re: 8.93 part b

that's because the w = -delta(nRT) equation only works when it's a gas because liquids and solids do not expand or change.
Sun Jan 21, 2018 10:57 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.77
Replies: 2
Views: 204

### Re: 8.77

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.
Sun Jan 21, 2018 1:44 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible and Irreversible
Replies: 4
Views: 302

### Re: Reversible and Irreversible

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.
Sat Jan 13, 2018 5:52 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Replies: 3
Views: 324

### Re: Question about Question 8.7

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....
Sat Jan 13, 2018 5:46 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: work equation
Replies: 2
Views: 168

### Re: work equation

Yes, It should always be applicable.
Tue Jan 09, 2018 9:15 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Specific Heat Capacity vs Heat Capacity
Replies: 5
Views: 367

### Re: Specific Heat Capacity vs Heat Capacity

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...