CHEMISTRY COMMUNITY

chari_maya 3B

Usually the integrated rate law is more applicable I believe.

chari_maya 3B

Can someone explain question 15b on Endgame? The lab finds that with these conditions, yield a pseudo rate constant k'. Show how k' is related to the real overall rate constant k. I am a little confused what the significance of a pseudo rate constant is. I also just don't understand the solution giv...

chari_maya 3B

Question 7.17E asks whether a catalyst accelerating the third step of a three step reaction would increase the overall rate of reaction. Why is the answer no?

chari_maya 3B

How can you tell the difference between a catalyst and an intermediary?

chari_maya 3B

Can someone explain the difference between K2/K1 and K'/K1? I thought the latter was equivalent to the equilibrium constant, is the former also? (are they just the same)

chari_maya 3B

Does that mean the midterm is going to be wayyyyyy more influential to our grade than it would have been?

chari_maya 3B

Is there a way to determine? I figured it would have to be given.

chari_maya 3B

There is a chart explaining this on page 595 of the textbook

chari_maya 3B

In zeroth order, rate is independent of concentration of reactant so long as it is present in some quantity, in first rate is linearly dependent etc.

chari_maya 3B

with unique average rates, you also don't have to specify the species

chari_maya 3B

Lyndon's reviews!!

chari_maya 3B

I am confused as to how the cathode/anode were determined. I thought they were interchangeable but if they were flipped, wouldn't this cause Q to be flipped as well?

chari_maya 3B

How do you find the half reaction for O2/O3, OH-? I know that the standard potentials are listed with the equations, in the appendix but I was wondering how to find this half reaction without looking in the back.

chari_maya 3B

Why is deltaG in Kj/mol in the answer... wouldn't number of moles (n) cancel with the moles in F?

chari_maya 3B

Why is the cell diagram reversed when the potential is negative? Is it because reversing is the only way to make the reaction favorable/spontaneous?

chari_maya 3B

The book lists the example: Pt(s)|H2(g)|H+(aq)||Zn2+(aq)|Zn(s), and states that the hydrogen electrode on the left is found to be the cathode. However, in another example, Pt(s)|H2(g)|H+(aq)||Cu2+(aq)|Cu(s), Cu is the cathode. Why is this/ how can you determine when the hydrogen electrode is the cat...

chari_maya 3B

Potassium and chlorine aren't used in the reaction because they are spectator ions, and their oxidation states don't change.

chari_maya 3B

Write the half-reactions and devise a galvanic cell (write a cell diagram) to study each of the following reactions: (b) H+(aq) + OH-(aq) ------> H20(l) the Brønsted neutralization reaction I got the correct answer for E standard, but I don't understand why oxygen is included in the cell diagram in ...

chari_maya 3B

Also how does oxidation state factor into balancing?

chari_maya 3B

Wait, hasn't Cr been oxidized because it has lost electrons not gained them (went from 2- to 3+)?

chari_maya 3B

If it is alkaline, why would you balance it first acidically?

chari_maya 3B

There is a difference: In acidic, balance O with H2O and H with H+, in basic it is more complicated but explained in Toolbox 6.K1

chari_maya 3B

I don't think the oxidizing/reducing agents are explicit in the half reactions, rather there is a focus on what gains/loses electrons.

chari_maya 3B

Why was 6.62607004 × 10-34 m2 kg / s super ripped?

because he did a lot of Plank

chari_maya 3B

Also, within the context of the isolated system, the change in entropy would equal zero, meaning that qsysystem= -qsurroundings, or would that be incorrect?

chari_maya 3B

How do properties of different ideal gases vary if they are essentially hypothetical?

chari_maya 3B

This was very helpful! I had the same question.

chari_maya 3B

Under what conditions would q =-cal?

chari_maya 3B

Actually I figured it out, it's because the system is losing energy and the surroundings are gaining energy, (-deltaSsys = deltaSsurr).

chari_maya 3B

The answer key states that rate of entropy generation = - rate of heat generation/T. Why is this negative? The final answer is positive.

chari_maya 3B

would this same concept apply to standard entropy of fusion?

chari_maya 3B

When deltaH is only given at temperature of vaporization.

chari_maya 3B

When using deltaS = qrev/T to derive the equation for entropy under isothermal and isobaric conditions, work is used in replacementf for qrev. Why is this, and why does the equation end up being positive when work is negative?

chari_maya 3B

What is the answer to this problem for part b?

chari_maya 3B

Is it possible to do this problem by finding total mass and only applying mcdeltaT once, or would that not work because of different heat capacities?

chari_maya 3B

The book states:
"work done during a reversible expansion of a gas is the maximum expansion work possible". Why is this true?

chari_maya 3B

When the external pressure is constant (Pex), this is an irreversible process. When external pressure changes slightly so Pex always equals Pin, then the reaction is reversible.

chari_maya 3B

According to the book, a reversible process in terms of thermodynamics is reversed by a very small change in a variable. However, I don't really understand conceptually the difference between this and an irreversible process. Can someone explain the theory behind this?

chari_maya 3B

Can someone explain how to solve this problem? The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise from 22.113 8C to 22.799 8C. The calorimeter assembly is know...

chari_maya 3B

Does superheating/supercooling only happen with pure substances?

chari_maya 3B

Is a bomb calorimeter an isolated system?

chari_maya 3B

The book states that "The constant-volume and constant-pressure heat capacities of a solid substance are similar; the same is true of a liquid but not of a gas". Why is this not true for a gas?

chari_maya 3B

Considering we've only had 2 lectures, I've only read 4.C and 4.D.

chari_maya 3B

Why can we do this? I understand that the rule exists, but I'm wondering if someone can explain how a small K correlates to a negligible x.

chari_maya 3B

Can someone solve this whole problem? I keep doing it and coming up with the wrong answer.

chari_maya 3B

Calculate Q first, which should produce a value of Q = 0.75. Because Q < Kc, the reaction proceeds in the forward direction, so reactants will lose concentration while products will gain concentration. Then do the ICE table and use quadratic equation to find Kc.

chari_maya 3B

In this problem: A reaction mixture consisting of 2.00 mol CO and 3.00 mol H2 is placed in a reaction vessel of volume 10.0 L and heated to 1200. K. At equilibrium, 0.478 mol CH4 was present in the system. Determine the value of Kc for the reaction CO(g) 1 3 H2(g) ∆ CH4(g) 1 H2O(g) at 1200. K. would...

chari_maya 3B

Why would you not convert to P and calculate Kp?

chari_maya 3B

does a change in concentration cause Kc to change?

chari_maya 3B

So is this why when the amount of reactant is increased, K remains the same for the reaction?

chari_maya 3B

what would happen if the reactant(s) and/or products are different states?

chari_maya 3B

Is this the same case for solids?

chari_maya 3B

How do you convert from Kc to Kp?

chari_maya 3B

Is a lewis acid/base always a bronsted acid and vice-versa?

chari_maya 3B

how does the Ch3 contribute electron density towards the O-H bond?

chari_maya 3B

^I am also wondering this... I saw another question asking whether HClO or HCLO2 is a stronger acid, I thought it was HCLO2 because more oxygen atoms are attached to the central atom, but the answer was HClO2 because ClO2- is more stable.

chari_maya 3B

Little Billy was a chemist
Little Billy is no more
What he thought was H2O
was really H2SO4!

chari_maya 3B

How do you draw diethylenetriammine chelating?

chari_maya 3B

How do you draw diethylenetriammine chelating?

chari_maya 3B

How do the Cl atoms attach to the DNA?

chari_maya 3B

What would H- be considered?

chari_maya 3B

is the answer to part a CH3COOK?

chari_maya 3B

I don't understand part b... I know that N is more electronegative than Zn so Zn(OH) must be the bronsted base, but I don't understand why it is Zn(OH)2.

chari_maya 3B

Why does losing one hydrogen make H22So4 a weaker acid?

chari_maya 3B

If sodium metal produces OH- ions when it reacts with water, why is it not considered a base?

chari_maya 3B

In carbon monoxide, is one of the bonds a coordinate covalent bond? I read somewhere that it was but there is no transition metal involved.

chari_maya 3B

What is the difference between a complex ion and a coordination compound?

chari_maya 3B

Right but the book says that the most common complexes have a coordination number of 6, why is that?

chari_maya 3B

what is a substitution reaction and under what conditions does it take place?

chari_maya 3B

Does it also have something to do with the variable valencies of transition metals and flexibility in oxidation states?

chari_maya 3B

From what I understand a Ligand is a lewis base that forms at least one coordinate covalent bond with the central atom which is generally a d block element.

chari_maya 3B

Why are terminal atoms not regarded as hybridized?

chari_maya 3B

Also, how can you predict whether a lone pair will be axial or equatorial?

chari_maya 3B

Why are lone pairs important in identifying shape when only the position of atoms are considered when naming the shape?

chari_maya 3B

Why are different strength bonds treated the same when applying VSEPR?

chari_maya 3B

Why is knowing the number of regions of electron density necessary when naming a molecule?

chari_maya 3B

I am also confused about this

chari_maya 3B

How is the lewis structure for H2C(NH2)COOH determined?

chari_maya 3B

How do you do part a, with ammonium chloride ?

chari_maya 3B

Will we have to know how to draw the lewis structure of a molecule given only the name of the molecule?

chari_maya 3B

Why can Br have 10 electrons, instead of 8?

chari_maya 3B

Can someone explain delocalized electrons?

chari_maya 3B

Why is the atom at the center of a lewis structure the one with the lowest ionization energy?

chari_maya 3B

Why is part C AlH3?

chari_maya 3B

Can someone explain why the difference between a compound of widely separated gases and tightly compacted ones is so drastically different?

chari_maya 3B

Why does gallium form Ga 3+ with the configuration [Ar]3d10?

chari_maya 3B

according the textbook, when sodium loses an electron (Na) - (Na +), the result has an electron configuration similar to neon, which is 1s1, 2s2, 2p6. Why does neon have this configuration, with only 1 electron in the 1s subshell?

chari_maya 3B

In what scenario would a valence configuration be used over an electron configuration?

chari_maya 3B

How do you draw an aufbau structure?

chari_maya 3B

Can someone help me with this problem?
Predict the number of valence electrons present in each of the following atoms (include the outermost d-electrons): (a) Ta; (b) Tc; (c) Te; (d) Tl.

chari_maya 3B

why are higher orbitals (g-,h- etc) not used by chemists in practice?

chari_maya 3B

what is the relationship between wave functions and orbital shapes?

chari_maya 3B

I don't really understand, conceptually, how the Schrodinger Equation was derived and proven. Can someone explain?

chari_maya 3B

Question 1.B.25 asks " What is the minimum uncertainty in the speed of an electron confined within a lead atom of diameter 350. pm? Model the atom as a one-dimensional box with a length equal to the diameter of the actual atom."

What does it mean by model the atom as a one-dimensional box?

chari_maya 3B

Wouldn't the total uncertainty be 10 m/s, because the uncertainty is 5.00 m/s +/- 5.0 m/s?

chari_maya 3B

How would you do this problem if the Lyman series did not apply?

chari_maya 3B

Can you explain the reason we know the correlation between UV light and the fact that n1 = 1?

chari_maya 3B

If that is true ( if excess energy is used to emit electrons and since the electrons are moving, the excess energy is basically manifested as the kinetic energy of the electron) then what would be the kinetic energy when the threshold energy is met exactly?

chari_maya 3B

How was the actual value of Planck's constant derived?

chari_maya 3B

One thinking point in the texbook asked why ultraviolet radiation is much more harmful to living tissue than infared radiation... I was wondnerinf if someone could explain the answer.

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