CHEMISTRY COMMUNITY

Michelle_Nguyen_3F

Hello! I understand that when determining whether a molecule is cis or trans, we give the higher priority to the atom with the larger atomic molecule. In this case, I know Br has the higher priority, but how do we know that it is trans since on the other side, they are both CH3 and thus have the sam...

Michelle_Nguyen_3F

Given $2Fe(s) + 2H_{2}O(l) + O_{2} \rightarrow 2Fe(OH)_{2} (s)$ , how would we write the half reactions? Thank you!

Michelle_Nguyen_3F

Could someone describe/break down their thought process in writing the IUPAC and the common name for $CH_{3}CH_{2}CH_{2}OCH_{2}CH_{2}CH_{2}CH_{3}$ ? Thank you!

Michelle_Nguyen_3F

Hello! I know that alkanes have the general molecular formula: C_{n}H_{2n+2} and that any compound with this carbon and hydrogen ration must be an alkane. In the course reader, it asks if we are able to determine the structure from the molecular formula. It then says we do not know the structure fro...

Michelle_Nguyen_3F

Why is NH3+ considered a nucleophile?

Additionally, what is the best way to determine if a molecule/atom is a nucleophile/electrophile? Is it best to just draw out the Lewis structures?

Thank you!

Michelle_Nguyen_3F

Hello! In the reaction mechanism example in the course reader, we said that the pi bond between the carbons in CH3CHCH3 was broken and that H--Br bond was broken. How did we know that the the carbon was partially positive and would be the atom to which the hydrogen would bond when a collision occurr...

Michelle_Nguyen_3F

Hello!

So I know that if we plot [A] vs time and we get a straight line, then the zero order reaction has a slope of -k. However, is it possible for k to be positive as well? Thank you!

Michelle_Nguyen_3F

Hello! I just wanted to make sure my reasoning is correct: If both of the half reactions are written as a reduction reactions, then the one with the higher reduction potential is more likely to be reduced, and is therefore the oxidizing agent and the cathode. The one with the lower reduction potenti...

Michelle_Nguyen_3F

A standard electrochemical cell is made by placing a silver electrode into a 1.0 M Ag + solution and a cadmium electrode into a 1.0 M Cd2+ solution. What is the redox reaction and what is the maximum potential produced by this cell? Be sure to show half reactions? How do we tell which is being oxidi...

Michelle_Nguyen_3F

In 2003 researchers developed a microbial fuel cell. In this fuel cell, bacteria generates electricity as it aerobically converts glucose into carbon dioxide and water: The balanced chemical reaction of glucose oxidation. C_{6}H_{12}O_{6} (aq) + 6O_{2}(g) \rightarrow 6H_{2}O (l&#...

Michelle_Nguyen_3F

Hello! The question is: Using the standard cell potentials: F_{2} (g)+ 2H^{+} (aq) + 2 e^{-}\rightarrow 2 HF (aq) Enot = +3.03V F_{2} (g) + 2 e^{-} \rightarrow 2 F^{-}(aq) Enot = +2.87V How do we determine which one is the cathode and which on is the anode bec...

Michelle_Nguyen_3F

Hello! I know that there are basically two forms of the Nernst Equation that we can use: 1) E_{cell}=E^{\circ}_{cell}-\frac{RT}{nF}lnQ and 2) E_{cell}=E^{\circ}_{cell}-\frac{0.0592}{n}logQ . In which situations would we use 1) vs. 2)? Can we use them interchangeably, or we will we get different answ...

Michelle_Nguyen_3F

Write the half-reactions and the balanced equation for the cell reaction for each of the follow galvanic cells: Pt(s)\left | O_{2}(g) \right |H^{+}(aq)\left \| OH^{-}(aq)\left | O_{2} (g)\right |Pt(s) How would you approach this problem, given that the...

Michelle_Nguyen_3F

In which situations/under which conditions would we use $w = - P\Delta V$ or $w = -nRTln\frac{V_{2}}{V_{1}}$ ?

Michelle_Nguyen_3F

Arrange the following substances in order of increasing standard molar entropy" CHF_{3}(g), CF_{4}(g), CH_{3}F(g), CH_{2}F_{2} (g) . The answer is given as: CH_{3}F(g) < CH_{2}F_{2} (g) < CHF_{3}(g) < CF_{4}(g) . I know that standa...

Michelle_Nguyen_3F

Comparing the molecular structures, you can see that benzene is unique for having double bonds between the carbons (sp 2 hybridized), so for each carbon there are 3 of sp2 hybrized orbitals interacting with the surrounding 2 carbons and 1 hydrogen. Since sp 2 hybridized orbitals are bonding, that l...

Michelle_Nguyen_3F

Yes, you would need to use \Delta G = \Delta H -T\Delta S. Since you know that \Delta H_{rxn}= \Sigma \Delta H_{f}(products)-\Sigma \Delta H_{f}(reactants) and \Delta S_{rxn}= \Sigma \Delta S(products)-\Sigma \Delta S(reactants) , then we can use \Delta G = \Delta H -...

Michelle_Nguyen_3F

In the Course Reader, on p. 36, it says that "More complex molecules have higher S^{\circ} due to a greater number of vibrational and rotational motions (atoms have a greater number of possible positions" which I understand. However,one of the homework questions, 9.71 asked "Which sub...

Michelle_Nguyen_3F

"In a combustion cylinder, the total internal energy changes produced from the burning of a fuel is -2573 kJ. The cooling system that surrounds the cylinder absorb 947 kJ as heat. How much work can be done by the fuel in the cylinder?" I know to use \Delta U = q + w. So \Delta U = -2573 kJ...

Michelle_Nguyen_3F

When we use bond enthalpies to calculate the total enthalpy change, how can we tell which bonds are broken and which bonds are formed? Is this skill more intuitive or is there a specific way to tell which bonds are broken/formed i.e looking at Lewis structures or the chemical reaction? Thank you!

Michelle_Nguyen_3F

I know that when reactants and products are in their standard state at 1 atm, the reaction enthalpy is the standard reaction enthalpy. However, how do we know that a reactant/product is in its standard state for any element? For example, I know that N_{2} is the standard state for N, but why is that...

Michelle_Nguyen_3F

Which of the following reactions can be classified as reactions between Bronsted acids and bases? For those that can be so classified, identify the acid and base. (Hint: It may help to write the net ionic equations.) d) NH_{4}I (am) + KNH_{2}(am) \rightarrow KI(am) + 2 NH_{3}...

Michelle_Nguyen_3F

Hi! I know somebody already asked this question, but I was still confused about the explanation. The question reads: "The two air pollutants SO3 and NO can react in the atmosphere as follows: SO_{3} (g) + NO(g)\rightarrow SO_{2}(g) + NO_{2}(g) . b) Give that a t ...

Michelle_Nguyen_3F

In the Course Reader, on page 160, it says that a salt containing a base will raise solution pH. When it says solution, is it just referring to a solution of the salt and water? How exactly does the salt increase the concentration of OH-? Also, it says that salts that contain the conjugate base (ani...

Michelle_Nguyen_3F

When trying to calculate the equilibrium compositions, how can we check to make sure that we can approximate x (by removing it from the denominator of the equilibrium constant calculation) and that is valid? I think Dr. Lavelle said something about it being valid if x was less than 5% of the initial...

Michelle_Nguyen_3F

Thank you!!

Michelle_Nguyen_3F

On page 138 in the Course Reader, we are given the example $N^{_{2}}(g) + 3H_{2}(g) \leftrightharpoons 2NH_{3}(g)$ . Could you please explain what happens if H2 is decreased and why? Thank you!

Michelle_Nguyen_3F

For each of the following weak acids, write the proton transfer equilibrium equation and the expression for the equilibrium constant K_{a} . Identify the conjugate base, writ ether appropriate proton transfer equation, and write the expression for basicity constant K_{b} .(a) HClO_{2} (b) HCN (c) C_...

Michelle_Nguyen_3F

Hello!
How would we determine if an acid is strong or weak? I understand that strong acids produce more proton in a solution than a weak acid, but how would we know that? Thank you!

Michelle_Nguyen_3F

For the complex ions listed below, determine the oxidation state and the coordination number of the central metal ion? [Fe(Cl)_{4}(en)]^{-2^} I know that the oxidation state is +2, but I am confused on how to get the coordination number. I know that the number of bonds is equal to th...

Michelle_Nguyen_3F

Hello! The question says: Benzyne, C6H4, is a highly reactive molecule that is detected only at low temperatures. It is related to benzene in that it has a six-membered ring of carbon atoms; but, instead of three double bounds, the structure is normally drawn with two double bonds and a triple bond....

Michelle_Nguyen_3F

Hello! My understanding of how to find the type of hybrid orbitals is to just count the regions of the electron densities and ensure that I have the corresponding hybrid orbital. For example, if there were to be three regions of electron density around the central atom, that means that the central a...

Michelle_Nguyen_3F

Hello! In the course reader on page 102, it says that that methane (CH4) structure has 4 equivalent covalent bonds that point towards the four corners of tetrahedron. It then says that carbon has only two unpaired electrons. Can someone explain that if C has only 2 unpaired electrons, how does it fo...

Michelle_Nguyen_3F

Hello! The question reads "Draw resonance structures for the trimethylenemethane anion C(CH₂)₃^2- in which a central carbon atom is attached to three CH₂ groups (CH₂ groups are referred to as methylene).

Thank you!

Michelle_Nguyen_3F

For each of the following ground-state atoms, predict the type of orbital from which an electron will be removed to form the +1 ion. (a) Ge; (b) Mn; (c) Ba, and (d) Au. Can someone please explain how they are going about this question? I'm getting the correct answers, but would like to know if I'm d...

Michelle_Nguyen_3F

"How many orbitals are in subshells with l equal to (a) 0; (b) 2; (c) 1; (d) 3?"

I know that this is a fairly basic question, but could some please explain how they got to their answer in detail and the reasoning behind the answer? Thank you!

Michelle_Nguyen_3F

Is it possible that video modules and assessments on atomic orbitals/wave function electron configurations could be created and/or posted? I personally found the video modules and assessments to be extremely helpful when reviewing and checking my understanding of the material lectured on in the clas...

Michelle_Nguyen_3F

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. I am a bit rusty on this, so my question is, how would we go about writing the net ionic equation for this particular reaction, or any reac...

Michelle_Nguyen_3F

The difference between the kinetic energy and the energy of the incident light is that the kinetic energy refers to the [b]energy of the ejected electron[/b ]. This can be found using the equation E_{k}=0.5\cdot m\cdot v^{2} , where m = mass of the electron and v = velocity of the ejected electron. ...

Michelle_Nguyen_3F

#6 in the Post-Module Assessment asks "In an atomic absorption spectrum what does one line (one wavelength) represent?" I understand the concept that atoms can only absorb and emit certain energies and that a line corresponds to the transition between two of the "allowed" energy ...

Search found 40 matches