CHEMISTRY COMMUNITY

lwon Dis2I

Can someone please explain how they did the problem below? I understand the general steps to getting the resulting heat enthalpy: 1) manipulate the given equations so that you get the amount of reactant or product for the equation you want 2) apply those numerical manipulations to the corresponding ...

lwon Dis2I

Thanks for your response! What if the two reactants seem to be neutral and balance each other out? How would you use the products to determine the type of reaction?

lwon Dis2I

How do you use the strength of bonds to determine whether a reaction will be endothermic or exothermic?

lwon Dis2I

When a bond is broken, it requires energy and is an endothermic reaction because you are basically making the bond less stable. Whereas when a bond is formed, it releases energy and is, therefore, an exothermic reaction because you are making the bond stable.

lwon Dis2I

When you are using a pressure cooker and release the steam, it would cause more severe burns than when coming into contact with water because it turned into vapor from boiling water through an increase in temperature.

lwon Dis2I

Hi can someone explain why the answer is charged? Below is the question. A monoprotic weak acid, HA , is ionized according to the reaction HA(aq)+H2O(l)↽−−⇀A−(aq)+H3O+(aq) pKa=3.84 where A− is the conjugate base to HA. For this weak monoprotic acid, the predominant species present at pH 5.64 is

lwon Dis2I

Can someone show me step by step how exactly they solve for x when using the quadratic formula for Wk 2 Sapling #3? I can never get the right answer and the number inside the square root is always negative somehow.

lwon Dis2I

What are the steps to find the percent ionization of a solution?

lwon Dis2I

What is a simple definition of percent ionization?

lwon Dis2I

What is the difference between (aq) and (l)? Why do we exclude H2O when calculating equilibrium?

lwon Dis2I

How do you know if a concentration change is small compared to the given initial condition?

lwon Dis2I

Why does inert gas not apply to the same rule of the effect of changing the pressure on the concentration?

lwon Dis2I

You use Kp when you are dealing with gases, but use Kc when you are dealing with molarity.

lwon Dis2I

How do you set up the ICE chart for this? Will H2 end up with 0.4M-X and I2 with 0.4M-X and 2HI with +2X as the equilibriums?

lwon Dis2I

I had the same problem as Darren. I just set up my equation as [HI^2}/{H2][I2] but the answer I got, in the end, was wrong. Why is this?

lwon Dis2I

The problem is:
At a certain temperature, 0.860 mol SO3 is placed in a 5.00 L container.
2SO3(g)↽−−⇀2SO2(g)+O2(g)
At equilibrium, 0.190 mol O2 is present. Calculate Kc.

How do you find the concentration of SO2 to then calculate Kc?

lwon Dis2I

How would you do this problem?

lwon Dis2I

How would you identify the pH level of a molecule just by looking at its chemical formula?

lwon Dis2I

How would you identify aqueous solutions as acidic or basic by their H+ or OH- concentrations?

lwon Dis2I

I notice that all the problems above are labeled to be at 25 degrees Celsius. How would the temperature affect the pH of substances?

lwon Dis2I

So basically to find the conjugate acid of a molecule, we add a hydrogen to it and give it a positive charge, and to find the conjugate base of a molecule, we take a hydrogen away from the molecule and make it a negative charge?

lwon Dis2I

Could someone elaborate more on Kyle's process of easily identifying the amphoteric substance out of a list of substances that you are given? I still do not quite understand. Are there any patterns we should look out for?

lwon Dis2I

What is the difference between pH=-log[H3O+] and pH=-log[H+]?

lwon Dis2I

Can someone explain more in detail of what bidentate means in a coordination compound and how it is different from a monodentate?

lwon Dis2I

Any tips for remembering how to name coordination compounds and remembering which suffixes to use?

lwon Dis2I

What is a chelating ligand?

lwon Dis2I

How would you identify a monodentate and a bidentate?

lwon Dis2I

What does it mean when the atoms lie in the same plane? The problem is below: Select the correct statement about the relative positions of the hydrogen atoms in the three structures. The hydrogen atoms of H2CCH2 and H2CCCH2 lie in the same plane. The hydrogen atoms of H2CCCH2 and H2CCCCH2 lie in the...

lwon Dis2I

What are delocalized pi bonds?

lwon Dis2I

Are there any other types of bonds other than sigma and pi bonds?

lwon Dis2I

What is a coordinate compound and examples of it?

lwon Dis2I

How can you determine if a bond is polar or nonpolar? And from looking at the polarity of the bonds, how would you judge whether the molecule as a whole is polar or nonpolar?

lwon Dis2I

How do you identify dipoles?

lwon Dis2I

How do you know if a molecule is polar?

lwon Dis2I

Can someone go through step by step how they would go about solving this?

lwon Dis2I

Can someone explain the different parts of the expression for the Coulomb potential energy?

lwon Dis2I

Can someone explain what lattice energy is and what causes it?

lwon Dis2I

Can someone explain what the difference is between electron affinity, ionization, and electronegativity? I keep getting so confused.

lwon Dis2I

I am slightly confused about drawing lewis structures, and specifically the octet rule. Do elements with 1 or 2 valence electrons have to fill an octet? For example, when drawing out a compound that contains the element Na (which has one valence electron), is it ever possible for it to fill the octet?

lwon Dis2I

What is the Van der Waals interaction between ions and molecules?

lwon Dis2I

How is the dissociation energy found for the strength of bonds?

lwon Dis2I

How is a polar covalent bond different from an ionic bond?

lwon Dis2I

How do you calculate Debye? Is it just the electronegativity difference between two atoms?

lwon Dis2I

Can someone explain what this equation (u=|q|d) means? Why is there an absolute value sign? What does the q stand for?

lwon Dis2I

Can someone explain why lone pairs on neighboring atoms repel each other?

lwon Dis2I

Can someone elaborate more on what radicals are? From what I understand, they are just atoms that are electron-deficient, but if I am missing another essential part of its definition, please let me know!

lwon Dis2I

Can someone break down the symbols and explain to me how this equation is derived?

lwon Dis2I

What is Midterm 2 going to cover?

lwon Dis2I

In the SO4 molecule, I know the final charge is -2, but how does it all add up if sulfur's formal charge is 0 and all four oxygens formal charge is -1? So (4(-1)+0)=-4 but not -2. Can someone explain how summing up the total charge of the molecule works using formal charge?

lwon Dis2I

Does formal charge have anything to do with oxidation numbers in the end?

lwon Dis2I

How do you know if an atom is isoelectronic in the first place?

lwon Dis2I

Just to make sure, the Rydberg equation can be used for all series like the Lyman, Balmer, Pacshel, and Brackett, right?

lwon Dis2I

The problem is: In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series or Lyman series, as shown in Fig. 1A.10). What is common to the lines within a series that makes grouping them together logical? The answer to it i...

lwon Dis2I

What does this symbol mean? I have not found anywhere in the book where it defines it.

lwon Dis2I

Can someone explain how to write the net ionic equation? And what is the original equation?

Copper(II) nitrate reacts with sodium hydroxide to produce a precipitate of light blue copper(II) hydroxide. (a) Write the net ionic equation for the reaction.

lwon Dis2I

The book seems to use B2O3 as the LR because it uses that reactant to solve for the mass of boron produced. Problem: Solid boron can be extracted from solid boron oxide by reaction with magnesium metal at a high temperature. A second product is solid magnesium oxide. (a) Write a balanced equation fo...

lwon Dis2I

Why does this problem give us three chemical reaction equations and not just one?

lwon Dis2I

How do you calculate the wavelength of a spectral line for the second part of the problem?

lwon Dis2I

What is the donut in the atom orbital dz^2 diagram?

lwon Dis2I

Can someone explain Schrodinger's equation with an example problem?

lwon Dis2I

Why did Professor Lavelle draw two detectors and not just one in his diagram today when explaining how the path of the electron would be interrupted by the light source?

lwon Dis2I

I found the lecture a bit confusing. Can someone explain how the units of the De Broglie equation cancel out to get to meters?

lwon Dis2I

Professor Lavelle went over the atomic spectra today, and he mentioned something about gases when describing the spectral lines. Can someone explain how "gases" are related to the spectra?

lwon Dis2I

Can someone walk me through how to do the problem below? When a metal was exposed to photons at a frequency of 1.15×1015 s−1, electrons were emitted with a maximum kinetic energy of 3.20×10−19 J. What is the maximum number of electrons that could be ejected from this metal by a burst of photons (at ...

lwon Dis2I

How would you solve this?

In the following ball-and-stick molecular structures, dark gray indicates carbon; white, hydrogen; blue, nitrogen; and green, chlorine. Write the empirical and molecular formulas of each structure. Hint: It may be easier to write the molecular formula first.

lwon Dis2I

Why should this answer be specifically three sig figs?

lwon Dis2I

Can someone walk me through how to solve this problem? An electron was ejected from the surface of an unknown metal. The ejected electron had 2.35 x 10^-18 J of kinetic energy. The photon used to eject the electron had 4.19 x 10^-18 J of energy. Calculate the work function (or threshold energy) of t...

lwon Dis2I

Thanks! Your responses help me understand a whole lot better. How would you find the amount of excess reagent?

lwon Dis2I

How do you convert the visible light of wavelength to Angstroms?

lwon Dis2I

I have not learned anything about Angstroms and cannot find a lot about it online. Can someone walk me through how to solve the problem below?

All of the organic compounds contain C and H as their essential elements, the bond length of C-H is 110 pm. Express the C-H bond length in Angstrom.

lwon Dis2I

How do you know which reactant is the limiting reactant?

lwon Dis2I

Also, what does the "d" below each of the reactants and products mean?

lwon Dis2I

How do you find the molar mass of 2‑butanone?

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