CHEMISTRY COMMUNITY

Amy Zheng 2l

I'm a little confused on the concept behind emf. What is the difference between emf and E

Amy Zheng 2l

Yes delta G stays the same, different activation energy

Amy Zheng 2l

For part b, how do we know which power to raise each concentration to? I thought that we can't raise concentrations to their respective coefficient in the equation.

Amy Zheng 2l

For part e, is it no effect because the activation energy itself is quite low for step 3? If the catalysis was applied to the entire reaction then would the rate increase?

Amy Zheng 2l

Is it possible to have multiple slow step in mechanism?

Amy Zheng 2l

Where did the solution manual get the equation ln(k'/k)=Ea/r(1/T-1/T') from?

Amy Zheng 2l

Yes there are multiple paths

Amy Zheng 2l

I don't believe any ochem will be covered since he will be finishing all new material on Monday and most likely spend the rest of the week reviewing!

Amy Zheng 2l

I think all of it will be on the final since it is listed on the syllabus and we do not have much more to cover for this chapter!

Amy Zheng 2l

What is the difference between rate constant and reaction rate?
How come increase in concentration doesn't increase rate constant but it does increase rate?

Amy Zheng 2l

Exothermic if energy after is less than energy before. But just because it is exothermic doesn't necessarily mean that it will be spontaneous as explained during thermodynamics. Spontaneity depends on delta G

Amy Zheng 2l

The graph would be straight if plotted against InA but it would be curved plotted against A

Amy Zheng 2l

For part B,how come we use In(Ainitial/Afinal)=kt? shouldn't it be -kt?

Amy Zheng 2l

In problem 5a, the oxidation reaction is: Br-->BrO3-
In problem 13a, the oxidation reaction is: H2->H+

How come for number 13, it's not h2->HCl but in 5 its br->BrO3-

Amy Zheng 2l

If I can only use delta s=q/t for reversible then does than mean that all the other entropy equation (ex: s=nRlnV2/V1) can only be used if the problem states that it is reversible?

Amy Zheng 2l

why is delta S surrounding for Irreversible expansion zero?

Amy Zheng 2l

The equations states that delta s=Qrev/T. If the reaction isn't reversible then does it mean that we can't use this equation to calculate entropy?

Amy Zheng 2l

Delta G=equilbrium

Amy Zheng 2l

its on the formula sheet!

Amy Zheng 2l

How come we dont have to do sum of Hproduct- sum of Hreactant to get H? While for S we do need to do product-reactant?

Amy Zheng 2l

basically entropy=0 in a perfect crystal because they must be in perfect order

Amy Zheng 2l

Negative=spontaneous=no energy need to be added to do work

Amy Zheng 2l

Amy Zheng 2l

whats the significance of saying " compressed suddenly (and irreversibly)". Why must they include irreversibly in the question?

Amy Zheng 2l

In the solution manual it said to assume ideal behavior and 1 mol of N2 gas

Amy Zheng 2l

What is considered regular hours?

Amy Zheng 2l

I remember Lavelle emailed us about getting back our finals during week 3. I was wondering where and when can I go get my test?

Amy Zheng 2l

I think the manual got 800 gram from the idea that 1L of water is approx 1000g. So 800ml of solution would equate to 800 gram. In the question it states to treat it as the same density as water.

Amy Zheng 2l

Is there a set rule for the relationship between q and w? I was thinking that if a reaction is negative q then the system is exothermic so work must be negative since you're loosing energy. If a reaction is positive q then the system is endothermic so work must be positive since you need to input en...

Amy Zheng 2l

In the question it states that the reaction produces heat but then delta H is negative. And I'm not sure if this is right, but I thought that heat would be negative since delta h is negative. BUT since the reaction produces heat that also leads me to think that heat would be positive. Basically I'm ...

Amy Zheng 2l

Gas is burned into the air

Amy Zheng 2l

the system is doing work on the surrounding so its negative

Amy Zheng 2l

No heat is transferred, thus q can't be anything else but zero

Amy Zheng 2l

Insulation usually means isolated

Amy Zheng 2l

Yes you would add the q and w to get u

Amy Zheng 2l

Yeah, I think 3 sig fig sounds right too

Amy Zheng 2l

areas of electron density gives you the hybridization. so like 2 areas of electron density=sp etc

Amy Zheng 2l

more O causes the electrons to be further away from the H, thus making it easier to break off from the compound.

Amy Zheng 2l

Because S is a nonmetal

Amy Zheng 2l

Concentration as stated by the formula. Brackets=concentration(mol/liter)

Amy Zheng 2l

favors product if K>1 and favors reactant is K<1

Amy Zheng 2l

Extra p orbitals not hybridized form pi forms

Amy Zheng 2l

Coordination number tells you the number of ions of opposite charge that surround the ion in a crystal.

Amy Zheng 2l

Yes, lone pair counts as region of e- density

Amy Zheng 2l

Its from the less electronegative atom to the more electronegative atom. So arrow goes from + ---> -

Amy Zheng 2l

it will not cover anything from chapter 4

Amy Zheng 2l

d orbitals can fit more electrons

Amy Zheng 2l

what happened to all the chemistry jokes? they're argon(all gone) hahahah

Amy Zheng 2l

yes as you move down the periodic table f ortibals come in. f sub shell has 7 orbitals so it can fit 14 electrons

Amy Zheng 2l

yep. if there's a period than all number to the left of it is counted as sig figs

Amy Zheng 2l

cu, half shell vs full shell

Amy Zheng 2l

There is no limit

Amy Zheng 2l

E4=1.36x10^-19
E1=2.1798x10^-18
E1-E4=2.04x10^-18
E=hc/wavelength
wavelength=9.7x10^-8 meters
answer is B

Amy Zheng 2l

Since it's a combustion question, the products and reactants for this equation are all in the gas state. You're burning Butane gas with the O2 in the air, creating h20(water vapor=gas) and Co2(gas). Add up all the coefficients on the product side(36) and all the coefficients on the reactant side(30)...

Amy Zheng 2l

Yes, the standard SI unit for mass is kg

Amy Zheng 2l

Generally I would round to the nearest whole number if its +/- 0.1 from a whole number. Often times numbers are off a little due to rounding errors.

Amy Zheng 2l

3 significant figures

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