CHEMISTRY COMMUNITY

Clarice Chui 2C

Can you tell what the order of a reaction is just by looking at it? If so, how?

Clarice Chui 2C

How can you tell if a cell diagram needs an inert metallic component?

Clarice Chui 2C

How do you know when the reaction is spontaneous to form either reactants or products?

Clarice Chui 2C

What are state functions and what are not state functions?

Clarice Chui 2C

What does the principle say about temperature? Like if it's endothermic or exothermic?

Clarice Chui 2C

How do you determine what the intermediate species is?

Clarice Chui 2C

Why is it useful/necessary to change a differential rate law to an integrated rate law?

Clarice Chui 2C

In lecture we used an example of using the method of initial rates to determine k and n, but can someone describe in words how to use this method?

Clarice Chui 2C

How does half life of a reaction relate to kinetics?

Clarice Chui 2C

How do you know when to reverse the reaction for the anode or the cathode? For reference I'm looking at the solution to 6L.3 part e.

Clarice Chui 2C

What is a calomel electrode and what are some applications for one?

Clarice Chui 2C

How do you calculate the equilibrium constant of a reaction from standard potentials?

Clarice Chui 2C

How do you find n from an equation for a reaction?

Clarice Chui 2C

What is the purpose of a salt bridge?

Clarice Chui 2C

For problem 6K.3, where did the 8 electrons come from on the balanced oxidation reaction?

Clarice Chui 2C

What is meant by the electrochemical series?

Clarice Chui 2C

How do you know if a metal will dissolve in a solution?

Clarice Chui 2C

If I'm looking at a typical picture of reaction in a galvanic cell, what would be the corresponding part to the single line(s) in a cell diagram?

Clarice Chui 2C

How does what we're learning in lecture apply to rust?

Clarice Chui 2C

What is the relationship between work and cell potential?

Clarice Chui 2C

Why is delta G positive when K is less than one and vice versa?

Clarice Chui 2C

What is the relationship between delta G and the equilibrium constant?

Clarice Chui 2C

Which is equation(s) would you be solving that uses Cv or Cp?

Clarice Chui 2C

With a reversible pathway, the temperature is constant, volume increases, and pressure decreases. With a reversible process, you can use delta S= rev/T. There is more work done, which can be calculated using w= -nRTln(V2/V1). With an irreversible pathway, temperature will change (decrease then incre...

Clarice Chui 2C

How do you calculate entropy for an irreversible path?

Clarice Chui 2C

under what conditions does free expansion occur?

Clarice Chui 2C

What is the relationship between heat capacity equation and enthalpy of phase change equations? Some questions don't give you, for example, the enthalpy of vaporization and liquid, so what do you do to calculate the enthalpy of of vaporization? Do you use the heat capacity equation?

Clarice Chui 2C

What kinds of reactions would a calorimeter be used for?

Clarice Chui 2C

what is the difference between a closed system and an isolated system?

Clarice Chui 2C

The book says that the steeper the slope on a heating curve, the lower is the heat capacity. I'm having trouble understanding this concept, so can someone please explain it? Thanks!

Clarice Chui 2C

Why do biological reactions occur at a constant pressure?

Clarice Chui 2C

What is the importance of degeneracy in relation to thermodynamics?

Clarice Chui 2C

Why is this equation negative?

Clarice Chui 2C

What does it mean to say that enthalpy is additive because it is a state function? I know this is Hess's Law, but I'm confused conceptually.

Clarice Chui 2C

Why, conceptually, does steam cause severe burns?

Clarice Chui 2C

I don't know if we'll ever have to calculate them, but so far he's given all of them to us.

Clarice Chui 2C

For all the examples, the H values were given, so I don't believe we'll be expected to find them unless we go over that later in the unit.

Clarice Chui 2C

What does Method 3 mean/ how can it be used? In lecture Professor Lavelle said to only use it when bond enthalpies aren't available but the example he used was a bit confusing for me to understand now that I look back. Can someone please explain this to me? Thank you! Yes please and can someone bre...

Clarice Chui 2C

When a reaction releases energy, or when it is exothermic, the value is negative. When the reaction absorbs energy, or is endothermic, the value is positive.

Clarice Chui 2C

I believe it's just the first one.

Clarice Chui 2C

Let's say that the partial pressure of a reactant was increased. How do you use Le Chatelier's principle/reasoning to predict and understand what happens?

Clarice Chui 2C

What is the example of osmotic pressure that we need to know? It says we should know it on the chemical equilibrium outline.

Clarice Chui 2C

On the outline, it says to know the biological example of ATP hydrolysis for chemical equilibrium. What is this example?

Clarice Chui 2C

How do you use equilibrium constants to predict solubility?

Clarice Chui 2C

Why do solutions of weak acids have higher pH values than solutions of strong acids at the
same concentration?

Clarice Chui 2C

How does changing concentration of the products affect an equilibrium reaction?

Clarice Chui 2C

What did Dr. Lavelle mean by the "quick way" of using Le Chatelier's Principle and what is the long way?

Clarice Chui 2C

What is the significance of Le Chatelier's Principle? How does it also apply to changing physical parameters?

Clarice Chui 2C

How do you figure out what the change in concentration is if you only have the initial concentration and the balanced equation? For instance, if you have the equation CO(g) + H2O(g) --> CO2(g) + H2(g) and the initial concentration of both of the reactants is 0.1M, how do you find the change in conce...

Clarice Chui 2C

If all the reactants and products are in the gas phase, do you have to use Kp? Or can you use Kc?

Clarice Chui 2C

What is the relationship between frequency and intensity?

Clarice Chui 2C

Naji Sarsam 4G wrote:The hydrogen bonding od DNA Base pairs, heme as a coordination compound, cisplatin for chemotherapy, vitamins as acceptors of dangerous radicals, the role of carbon dioxide in blood ph

These are the examples i can think of

can you elaborate on the vitamins?

Clarice Chui 2C

can you tell if a compound is a chelate just by looking at it?

Clarice Chui 2C

how do you find hybridization of lone pairs?

Clarice Chui 2C

Hi! Can someone please explain dipole induced dipole and how it's different from other forces along with an example?

Clarice Chui 2C

What are the properties that determine how strong an acid is? Why is HI a stronger acid than HF?

Clarice Chui 2C

Can someone please explain all the parts of the pH equation?

Clarice Chui 2C

What is the biological significance of EDTA?

Clarice Chui 2C

If a compound is outside of the coordination sphere, that means that that compound is not directly attached to the metal or central atom. When drawing, do not attach the compound to the central atom.

Clarice Chui 2C

Relating to the chelate part of your question, a chelate is a complex containing a ligand that forms a ring of atoms that includes the central metal atom. Chelating ligands bind cations tightly and are significant in nature especially. For example, the book discusses how chelating ligands lie behind...

Clarice Chui 2C

What is a heme complex? What is the biological significance of heme complexes?

Clarice Chui 2C

Transition metals have many oxidation states, so they are good for electron transfer.

Clarice Chui 2C

In order to find the oxidation state of a transition metal, find the charges of the atoms around the central atom. Whatever those charges add up to, subtract that from the formal charge of the molecule as a whole. So for example if the formal charge of the molecule was neutral and the surrounding at...

Clarice Chui 2C

What is the difference between Lewis acids + bases and Bronsted acids + bases?

Clarice Chui 2C

Cis means that the electronegative atoms around the central atom are all on the same side. This means it’s polar. Trans means that the atoms around the central atom are opposite each other, making it symmetrical and nonpolar. Cisplatin is a well-known chemotherapy drug that forms a coordination comp...

Clarice Chui 2C

When trying to find which molecule has a greater boiling point, which factors should be considered first/weighted the most in solving? Electronegativity? Molar mass/size? Etc?

Clarice Chui 2C

Hi! Okay so there are only two leftover electrons because the molecule has a +1 charge. Cl is therefore surrounded by 3 "things," aka regions of electron density (one for each double bond to oxygen and one for the lone pair on Cl). The lone pair on Cl makes it trigonal planar. Hope that cl...

Clarice Chui 2C

b) (CH3)2Be
I drew the Lewis structure no problem, but why is the shape tetrahedral?

Clarice Chui 2C

a) AX4E
- seesaw

b) AX3E2
- T-shaped

c) AX4E2
- square planar

d) AX3E
- trigonal pyramidal

Clarice Chui 2C

a) The shape is trigonal pyramidal because there are four regions of electron density. 3 of those are bonds between atoms and the fourth is a lone pair. b) All the OSCl angles are the same because the lone pair pushes away the bonded pairs equally. c) the angles are >109.5

Clarice Chui 2C

Why do London forces act between all molecules rather than just between nonpolar molecules?

Clarice Chui 2C

Another factor that affects bond strength is delocalization (related to resonance as said above).

Clarice Chui 2C

So electron distortion is proportional to the polarizability of electrons. What does electron distortion really mean?

Clarice Chui 2C

Why does fluctuating electron distribution result in fluctuating dipoles?

Clarice Chui 2C

So in lecture we talked about how larger atoms/ atoms with higher molar mass have stronger attractive interactions, so does that help explain why, for example, F subscript 2 is a gas at room temp while I subscript 2 is a solid? The bigger the atom --> the stronger the bond --> the more solid it is a...

Clarice Chui 2C

Also, Hydrogen bonding helps explain higher melting points.

Clarice Chui 2C

Also, Hydrogen will never be the central atom just fyi!

Clarice Chui 2C

What is the difference between electron affinity and electronegativity?

Clarice Chui 2C

Does anyone have an easy way to remember the full names for n, l, and ml?

Clarice Chui 2C

^ yes I believe anything less than that would be undetectable and too small to be considered having wave-like properties.

Clarice Chui 2C

Is there an easier way to calculate this/remember it/shortcut?

Clarice Chui 2C

What is hybridization of the central atom?

Clarice Chui 2C

What does the E stand for in AXE?

Clarice Chui 2C

Triple bonds are shorter than both double bonds and single bonds, but they are stronger than both of those. Single bonds are longer than both double and triple bonds, but are also weaker than both of those.

Clarice Chui 2C

He also mentioned that hydrogen will never be the central atom. Just something to remember!

Clarice Chui 2C

What is the difference between electronegativity and effective nuclear charge?

Clarice Chui 2C

So i know the exceptions to normal electron configuration, but why are these elements structured the way they are?

Clarice Chui 2C

^ Just to add, m sub s can either be +1/2 or -1/2. If it is positive, the electron is spin up and if it is negative, the electron is spin down.

Clarice Chui 2C

When an electron is located in specific planes, what does that mean?

Clarice Chui 2C

To add, there are 2l + 1 different values for m sub l.

Clarice Chui 2C

The example from lecture resulted in the velocity of the electron being greater than the speed of light. Obviously this is not possible, but what does that unrealistic answer tell us about the electron? Something about being localized at the nucleus?

Clarice Chui 2C

What exactly is diffraction?

Clarice Chui 2C

Can someone give a little for context for when to actually use this equation?

Clarice Chui 2C

In reference to electrons being excited and jumping to higher energy levels, is there a specific number of levels each element has? Or is the number of energy levels infinite?

Clarice Chui 2C

Can someone clearly differentiate between intensity and frequency?

Clarice Chui 2C

Why does threshold energy/work function differ?

Clarice Chui 2C

What are the conversions between Kelvin, Celsius, and Fahrenheit again?

Clarice Chui 2C

As long as you remain consistent with units throughout your work and the problem doesn't explicitly ask for a specific unit of measure, it shouldn't matter.

Clarice Chui 2C

So just to clarify, the higher the percent yield, the better? That means that the actual yield is close to the theoretical right?

Clarice Chui 2C

Some reasons for this are side reactions, impurities, some compound sticking to the side of the equipment it's in, human error in measurements.

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