CHEMISTRY COMMUNITY

Charlene Tang 1B

Plot t against [A], and if you get a straight line with negative slope, it's zero order.

Hope this helps! :)

Charlene Tang 1B

If there's a cyclopentane with 2 methyl groups attached to one of the carbons and 1 isopropyl group attached to the carbon next to that, would the name of the structure be 1-isopropyl-2,2-dimethylpentane? This is number 16 on chapter 1 of the Ochem book and the answer key says the answer is 2-isopro...

Charlene Tang 1B

I'm going to assume the K for the overall reaction is the K for the forward reaction. If you're given the K (equilibrium constant) for the reverse reaction, all you need to do is just 1/K reverse to get the K forward . If K is large (or just >1), then concentration of the products is larger than tha...

Charlene Tang 1B

A unique rate is the rate of appearance/disappearance of any of the species in a reaction divided by its stoichiometric coefficient. Since the coefficients aren't taken into account in the average rate, it might be different from the unique rate.

Hope this helps!

Charlene Tang 1B

The positivity/negativity of the slope has nothing to do with concentration, but rather the order of the reaction. We can use the 2nd order differential rate law to obtain (-1/a)(d[A]/dt)=k[A]^2 --> (-d[A]/[A]^2) = kdt When you integrate that you'll get 1/[A] = kt + 1/[A] o , and when you plot 1/[A]...

Charlene Tang 1B

When do we know to use w=-nRTln(V2/V1) rather than w=-P∆V?

Charlene Tang 1B

This is 9.13 on the homework. During the test of an internal combustion engine, 3.00 L of nitrogen gas at 18.5 C was compressed suddenly (and irreversibly) to 0.500 L by driving in a piston. In the process, the temperature of the gas increased to 28.1 C. Assume ideal behavior. What is the change in ...

Charlene Tang 1B

Why is ∆U zero in isothermal reversible expansion?

Charlene Tang 1B

This is #51 on the homework. The enthalpy of formation of trinitrotoluene (TNT) is 67 kJ/mol and the density of TNT is 1.65 g/cm^3. Explore its potential as a rocket fuel by calculating its enthalpy density (enthalpy released per liter) for the reaction: 4C 7 H 5 N 3 O 6 + 21O 2 --> 28CO 2 + 10H 2 O...

Charlene Tang 1B

Ok I'll try to tackle these one at a time. Change in entropy = Boltzmann's Constant * ln (w2/w1) ^ Because entropy by itself is S=(kB)*ln(W), ∆S will be (kB)*ln(W2) - (kB)*ln(W1). Which can be simplified, using log rules, to ∆S=(kB)*ln(W2/W1) <-- this calculates the change in entropy per particle Si...

Charlene Tang 1B

Heat is not a state function because it depends on the pressure during heating/cooling and not just the initial and final temperatures and pressure, while enthalpy is measured at constant pressure. State functions are step independent functions and only the initial and the final values matter, not t...

Charlene Tang 1B

Acetic acid is used as a solvent for some reactions between acids and bases.
a) Nitrous acid and carbonic acid are both weak acids in water. Will either of them act as a strong acid in acetic acids?
b) Will ammonia act as a strong or weak base in acetic acid?

Charlene Tang 1B

How does change in pressure and temperature affect density?

Charlene Tang 1B

In class, Dr. Lavelle said that the shifting of reactions doesn't necessarily depend on whether one side has more moles of gas than the other. Why doesn't adding a nonreactive gas (like He) and increasing the pressure affect the shifting of reactions?

Charlene Tang 1B

How do you determine if a ligand can be polydentate and the maximum number of places on the ligand that can bind simultaneously to a single metal center? For instance, why is HN(CH2CH2NH2)2 tridentate? How would polydentate ligands affect the oxidation number of the coordination compound? For exampl...

Charlene Tang 1B

Why is XeF2 non polar? Doesn't it have lone pairs?

Charlene Tang 1B

Does a higher bond order mean that the molecule is more stable?

Charlene Tang 1B

1. According to the book, molecules that are AX3E2 are T-shaped. The illustration of the molecule shows that the lone pairs replace 2 of what would be the equatorial atoms, which would make them 120 degrees from each other. Since there is electron repulsion, why don't the lone pairs replace the top ...

Charlene Tang 1B

111. A common biologically active radical is the pentadienyl radical, RCHCHCHCHCHR', where the carbons form a long chain, with R and R', which can be a number of different organic groups, at each end. Draw three resonance structures for this compound that maintain carbon's valence of 4. I was just w...

Charlene Tang 1B

The question asks us to draw the most important Lewis structure for the N 5 + ion, including all equivalent resonance structures. How come the most important Lewis structures, according to the solution manual, have no two like formal charges near one another? Why can't we have 3 identical formal cha...

Charlene Tang 1B

For the Lewis structure for glycine (H2C(NH2)COOH), does the 2 oxygens have to bond with the same carbon like it did in the answer key? Or does it not matter as long as we have 30 electrons?

Charlene Tang 1B

The p orbitals can fit a total of 6 electrons in its 3 orbitals. Elements in group 15 have 1 electron in each of the 3 orbitals, so it makes sense that it'll take more energy than expected to add another electron to the same orbital because of electron-electron repulsion.

Hope that makes sense!

Charlene Tang 1B

Lines in the Balmer series of the hydrogen spectrum observed at 656.3, 486.1, 434.0, and 410.2 nm. What is the wavelength of the next line of series? I'm just unsure as to how to approach this question. Does Balmer series mean that the electron always return to n=2? Or can it be n=3 or other numbers...

Charlene Tang 1B

Oh my goodness thank you so much!
That must have taken quite a while to write.

And Alina I think you do that when you're given mass percentages or have calculated them so you can carry out the rest of your calculations easier.

Charlene Tang 1B

1. A compound found in the nucleus of a human cell was found to be composed of carbon, hydrogen, oxygen, and nitrogen. A combustion analysis of 1.35g of the compound produced 2.20g of CO2 and 0.901g of H2O. When a separate 0.500g sample of the compound was analyzed for nitrogen, 0.130g of N2 was pro...

CHEMISTRY COMMUNITY

Search found 25 matches

Re: Determining zero order reactions

Naming Structures

Re: Finding K

Re: What is the "unique rate of reaction"?

Re: Slope of a Second Order Reaction Plot

When to use which formula

When to use R or C?

∆U in Isothermal Reversible Expansion

Calculating Enthalpy Density for a Reaction

Re: Clairifcation on when to use entropy equations.

Re: heat and state function

Weak Acids Acting As Strong Acids

How Density is Affected

How Pressure Affect Reactions

Polydentate and Oxidation Numbers

Polarity of XeF2

Bond Order and Bond Stability

VSEPR - T-shaped Molecules and Bond Angles

Chapter 3 Question 111 + Radicals

Chapter 3 Question 99

Lewis structure for glycine

Re: group 15 electron affinity

Question 1.57 - Different Series

Re: 2 Questions from M. Limiting Reactants

2 Questions from M. Limiting Reactants