CHEMISTRY COMMUNITY

Rachael_1H

Why would the pOH decreasing cause the OH- concentration to increase? Wouldnt it decrease according to the equation pOH=-log[OH-]?

Rachael_1H

Are the prefixes "neo" and "tert" interchangeable? If not, how do you know when to use which?

Rachael_1H

How do you know what to capitalize when naming compounds? For example, 4-tert-Butyl-1,2-dimethylcyclohexane has a capitol "B" in "Butyl" but not a capitola "M" for "methyl". Why? When do you and do you not capitalize?

Rachael_1H

When Calculating K with the equation log K=(n)(standard E)/(0.0592), using the values log K=(2)(-.45 V)/(0.0592), K=6.27*10^-16 but the book rounds this value to K=6*10^-16. Why is only one significant figure the correct amount of sig figs? Shouldn't it be 2 sig figs because the mantissa of the loga...

Rachael_1H

If the standard potential of cathode > standard potential of anode, why does the reaction favor products? And what does this have to do with K>1? From looking at a list of reactions, how would you know which have a value of K>1?

Rachael_1H

When calculating the standard potential for a half reaction, such as U4+ + 4e- ---> U, why do you have to convert the standard potentials of the half reactions U4+ + e- ---> U3+ and U3+ + 3e- ---> U to their standard delta G values, and then add their standard delta G values to find the standard pot...

Rachael_1H

When Writing a Cell Diagram, how do we know which order to put the different molecules of the anodes and cathodes in? For instance with the anode: Ag --->Ag+ + e- and the cathode: O3 + H2O + 2e- ---> O2 + 2OH- , the cell diagram is: Ag(s)|Ag+(aq)||OH-(aq)|O3(g),O2(g)|Pt(s) My question is: why is Ag ...

Rachael_1H

When Writing a Cell Diagram, how do we know which order to put the different molecules of the anodes and cathodes in? For instance with the anode: Ag --->Ag+ + e- and the cathode: O3 + H2O + 2e- ---> O2 + 2OH- , the cell diagram is: Ag(s)|Ag+(aq)||OH-(aq)|O3(g),O2(g)|Pt(s) My question is: why is Ag ...

Rachael_1H

Calculate standard gibbs free energy of a reaction for the reaction showing the decomposition of mercury (II) oxide at 298 K. 2HgO(s)---> 2Hg(l) + O2(g) Standard reaction enthalpy of formation for HgO = -90.83 standard molar entropy HgO=70.29, Hg=76.02, and O2=205.14 When finding the standard gibbs ...

Rachael_1H

Thank you. How do you know whether The reactants' bonds are breaking or forming? I understand that you look at the chemical equation, but for the equation
Ch4 + 2O2 ----> CO2 + 2H2O
For instance, are the reactants' bonds breaking? Does this make it exothermic?

Rachael_1H

A sample of one mole of gas initially at one ATM and 298 K is heated at constant pressure to 350 K then the gas is compressed isothermally to its initial volume and finally it is cooled to 298 K at constant volume. Which of the following values is zero? Delta S surroundings and Delta G Delta S syste...

Rachael_1H

When calculating the standard rxn entropy and enthalpy, using standard molar entropies and enthalpies, how do you know whether to subtract sum of products from sum of reactants, or vice verse? Our course reader says: Standard RXN Entropy/Enthalpy=(sum of products' standard molar entropies/enthalpies...

Rachael_1H

Why does "1 mol of the atoms of an ideal monatomic gas" have a greater change in entropy than "1 mol of atoms bound together as diatomic molecules" when temperature in increased? The book's answer key says it is because the 1 mol of atoms of an ideal monatomic gas has "a gre...

Rachael_1H

Hi, I'm looking for help with homework question 8.49, which states, "Oxygen difluoride is a colorless, very poisonous gas that reacts rapidly with water vapor to produce O2, HF, and heat. It gives the formula OF2 (g) +H20 (g) --> O2 (g) + 2HF (g) with delta H being -318 kJ. What is the change i...

Rachael_1H

20 grams of Copper at 100 degrees celsius is put in a vessel containing 50.7 grams water at 22 degrees celsius. Assume no energy is lost to surroundings. When finding the final water temperature, why do you set the +(heat released)= -(heat absorbed)? Why do you make the "heat absorbed" neg...

Rachael_1H

Using bond enthalpy to determine the enthalpy change of the rxn: H2(g) + (.5)O2(g) -----> H2O(l) The equation used is sum of bonds broken minus sum of bonds formed. Using the book's given bond enthalpies of diatomic molecules and mean bond enthapies, the answer key has the equation used as (H2 bond ...

Rachael_1H

How do you know the volume of acid added? Only the molarity of HCl, the acid, is given.

Rachael_1H

My question is from the text: 12.67) Rank the following solutions in order of increasing pH: A) .00005 M HCl B) .2 M CH3NH3Cl C) .2 M CH3COOH D) .2 M C6H5NH2 justify your ranking. How would you determine the ranking? Would you need to calculate the pH of each solution, and if so how would you do tha...

Rachael_1H

Can someone please explain this problem from the textbook to me, step by step? 12.65) Determine whether an aqueous solution of each of the following salts is basic, acidic, or neutral. Write a chemical equation to justify your answer. A. KBr B. AlCl3 C. Cu(NO3)2 I mainly am confused by why the answe...

Rachael_1H

What is electron withdrawing and how do we know how electron withdrawing a bond is?

For instance, the answer key to our text states that the bond between the CCl3 group and COOH group in C2HCl3O2 is more electron withdrawing than the CH3 group in C2H4O2, which makes C2HCl3O2 a stronger acid.

Rachael_1H

Hello,

"state whether the following oxides are acidic, basic, or amphoteric:
As2O3 and Bi2O3."

The answer key states that they are both amphoteric. How would we know this?
Please explain. Thanks.

Rachael_1H

In the Chemistry 14a Course Reader on page 139, Lavelle has written: " -log(1.7 * 10^(-12)) = -(-11.8) = 12 " I am confused how he got to the value -11.8 from the equation -log(1.7 * 10^(-12)). Could someone please explain to me how to solve this logarithm (along with logarithms in general...

Rachael_1H

Problem 11.13 from our book states "Write the reaction quotient Q for: 2BCl 3 + 2Hg => B 2 Cl 4 + Hg 2 Cl 2 " and in our answer key the answer is \frac{1}{P_{BCl_{3}}} I am confused at how to get to this answer. I thought that we find Q the same way that we find K: [products]/[reactants] H...

Rachael_1H

Yes the bond angles would be slightly less than 90 degrees because of the two lone paires

Rachael_1H

Hello,

How do we determine the bond angles for angular, trigonal pyramidal, t-shaped, see-saw, and square pyramidal molecules? They are not written in the book on page 109.

Rachael_1H

"How many grams of ammonium chloride are needed to have 3.4 * 10^(-4) moles?" From this question, which is from the second Quiz #1 Self Preparation Quiz, how are we supposed to figure out the formula for ammonium chloride without outside resources? Are there certain formulas that we are su...

Rachael_1H

"Calculate the volume of .642 M KOH that should be used to make 1.00 L of .101 M KOH." Why is the answer to this in mL when the unit of L is used within the problem? The correct answer to the problem is 157 mL according to the answer key, but would answering the question with .157 L be con...

Rachael_1H

In our text it states that "an effective nuclear charge for an electron in a p-orbital is lower than an electron in an s-orbital in the same shell" for multi electron atoms. I am confused because our course reader states "s-electrons have a lower energy than p-electrons in the same sh...

Rachael_1H

Is a lobe the same thing as a radial node?

Rachael_1H

Is a lobe the same thing as a radial node?

Rachael_1H

Hello. What is a sulfide and how do we find a sulfide's molar mass? I came across a problem in the fundamentals section of the textbook that required knowledge of sulfides: "The molar mass of the metal hydroxide M(OH)2 is 74.10 g/mol. What is the molar mass of the sulfide of this metal?"

CHEMISTRY COMMUNITY

Search found 31 matches

Re: pH and cell potential

Tert vs neo

naming compounds

Significant Figures

Standard potential and K

Find stndrd potential of 0.5 rcn using stndrd delta G values

Writing cell diagram: figuring out order

Writing cell diagram: figuring out order

calculating standard gibbs free energy of reation

Re: Standard RXN Entropy/Enthalpy

Knowing when a value is equal to zero

Standard RXN Entropy/Enthalpy

Ideal Monatomic Gas Entropy

Finding change in internal energy using PV=nRT equation

Heat Capacities

Mean Bond Enthalpy

Re: HW 13.23

Determine ranking of pH of solutions [ENDORSED]

Salt pH in Aqueous Solution

Electron withdrawing

Amphoteric

Writing Molarity of IONS as Logarithms: Solving Logarithms

Reaction Quotient Q

Re: Bond Angles for Angular, T-shaped, etc.

Bond Angles for Angular, T-shaped, etc.

Quiz 1 Preparation: Naming Simple Compounds

Units on Quiz #1 Preparation [ENDORSED]

Multi electron atom effective nuclear charge

Orbitals: lobes vs. radial nodes

Orbitals: lobes vs. radial nodes

Sulfides