CHEMISTRY COMMUNITY

Tia Tomescu 2D

The Vant Hoff equation comes by setting the two delta G equations as equal.

Tia Tomescu 2D

If delta G is negative then the reaction will occur.

Tia Tomescu 2D

Helium. Helium. Helium.

Tia Tomescu 2D

As far as I know, the class is not graded.

Tia Tomescu 2D

When calculating Q and K will can molarity and pressure be used interchangeably?

Tia Tomescu 2D

I think you have to use deltaG=-nFE to calculate this.

Tia Tomescu 2D

No because the first law is deltaU = q + w and but equation you have is only related to q.

Tia Tomescu 2D

Q3) Mn2+ (aq) + Br2 (l) → MnO4- (aq) + Br- (aq) Balance the redox reaction. Is the correct answer 8(H2O) + 2(Mn2)+ + 5(Br2) --> 16(H+) + 2(MnO4-) + 10(Br-) ?

Tia Tomescu 2D

Question: A balloon filled with 31.9 mol of Helium has a volume of 876 L at 0oC and 1.00 atm pressure. At constant pressure, the temperature of the balloon is suddenly increased to 38.0oC , causing the balloon to expand to a volume of 998L. (The molar heat capacity of Helium is 20.8 J/ oC mol) How m...

Tia Tomescu 2D

If an isolated system contained +100 kJ of energy, after 100 years why will the internal energy be 0? (UA workshop week 2 question 3)

Tia Tomescu 2D

[A] is concentration (at any time), and [A]₀ is concentration at t=0.

Tia Tomescu 2D

Basically, if the reaction will proceed even with a little bit of reactant and will not make more or less product if you increase or decrease the concentration of reactants then it is independent of the rate.

Tia Tomescu 2D

How did we get 0.693 in the equation?

Tia Tomescu 2D

To add on to that, in real life situations the left might not be the anode, it is just standardized like so in textbooks so that it is easier to comprehend.

Tia Tomescu 2D

I believe the (mol O2) is just to specify that the answer is for the moles of O2. Usually when we answer questions we don't need to specify that.

Tia Tomescu 2D

Both are studying reactions, but thermodynamics is only concerned with the initial and final states while kinetics factors in the speed of the reaction--their rates.

Tia Tomescu 2D

You can calculate it through a series of steps.

1) Increase temperature from 25 C to 100 C
2) Find the enthalpy of vaporization of water (l -->g)
3) Lower the temperature of the water vapor from 100 C to 25C

Hope that helped!

Tia Tomescu 2D

Page 281 of the textbook gives a good summary of the Cp and Cv for atoms, linear molecules, and nonlinear molecules.

Tia Tomescu 2D

Yes, it is the number of moles of electrons.

Tia Tomescu 2D

Looking at the equation deltaG°=-RTlnK, if K=1, that means the products and reactants are of the same concentration, and thus lnK=0, and deltaG° will equal 0.

Tia Tomescu 2D

Thermodynamically favored means the reaction will proceed spontaneously, and it refers to deltaG, the free energy.

Tia Tomescu 2D

To add on to that, the system is at equilibrium when entropy is at a maximum.

Tia Tomescu 2D

Because pressure is increased so we can't use the second equation (Cv is at constant pressure!)

Tia Tomescu 2D

Yes, when the value of entropy is positive the process is spontaneous. The equation just spells this out in math. It it true that when V2 is larger than V1, there are more possible positions, so entropy is positive. (spontaneous reaction) But V2 can also be smaller than V1 in which case the equation...

Tia Tomescu 2D

I think there still might be concept questions relating to the topic, but just not calculations.

Tia Tomescu 2D

It could be argued that the universe is a "perfectly" isolated system!

Tia Tomescu 2D

Could anyone explain to me they difference between work done on the system and work done by the system? I have trouble grasping the concept of work and the system.

Tia Tomescu 2D

This is a good observation, I do not have a solution manual, but when I solved this question I did this: (-1107)(-3/2)+(-1676)=15.5kJ which rounds to 16kJ. This is the correct answer in the answer manual. But in fact, the oxygen will not be canceled out. The product side will have 3/2 O2 and the rea...

Tia Tomescu 2D

I checked my equations many times, but my value always comes to -38.72kJ while the answer is 15.28kJ. The previous two questions, (a) and (b) are similar to (c) and I used the same method: enthalpy of products - enthalpy of reactants. Does anyone know how to solve this?

Tia Tomescu 2D

My answer was 448.5 which I rounded to 449. But the answer was 448. Does anyone know why?

Tia Tomescu 2D

Why is Formic acid a stronger acid than Acetic?

Tia Tomescu 2D

I noticed in 12.53 only the names of the compounds were given. Are we supposed to know the formulas by heart?

Tia Tomescu 2D

Why is HF a weak acid and HCl a strong one, while C2O2HF3 is a stronger acid than C2O2HCl3?

Tia Tomescu 2D

Nicole, yes, that is true for polar molecules.

Tia Tomescu 2D

Why does hydrogen have a relatively high electronegativity?

Tia Tomescu 2D

Also, just to add, the common Electronegativity chart that we use now is based on the Pauling's scale, which I believe uses the disassociation energy of diatomic bonds to calculate the disassociate energy of a molecule if it were a purely covalent bond. Then it measures the difference between the ac...

Tia Tomescu 2D

Today in lecture Professor Lavelle said that Fluorine's formal charge cannot be +1 because it is highly unstable. Why is this?

Tia Tomescu 2D

Based off of the homework questions in the textbook, believe we need know how many nodal planes there are for the s p d orbitals. (However, if you look at the assigned homework, questions regarding the nodal planes were skipped.)

Tia Tomescu 2D

This is what I did:

v/c=3600cm^-1
v/c=36m^-1
v=36 x c
v=36 x 3x10^8
v=1.1x10^10 (1/s)

Yet the answer is 1.1x10^14 (1.s)

Does anyone know what went wrong with my method?

Tia Tomescu 2D

1.15 In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line. I used \frac{1}{\lambda }=R_{H}(\frac{1}{n1^2}-\frac{1}{n2^2})...

Tia Tomescu 2D

For Question E29, the question only gives a number with 3 significant figures (8.61), yet the answer for (d) on the textbook is 4 sig figs (0.3099). Does anyone know why?

Tia Tomescu 2D

In my opinion, L7 (b) states "What mass of oxygen is needed to oxidize this amount of tristearin?" Since they're asking for the same amount (454g), you should still continue using 454g as the amount of tristearin to solve the problem.

Search found 42 matches