## Search found 26 matches

Mon Mar 09, 2015 12:05 am
Forum: General Science Questions
Topic: Positive and Negative Delta G
Replies: 1
Views: 1483

### Positive and Negative Delta G

Hi,
I just want to make sure on this, I need to refresh my memory.
When the reaction free energy is <0 is exergonic, and therefore products are favored? or are reactants favored?

Thank you!
Sun Feb 22, 2015 8:21 pm
Forum: General Rate Laws
Topic: Unique Average Reaction Rate and Chemical Equation
Replies: 1
Views: 603

### Unique Average Reaction Rate and Chemical Equation

Thinking point page 563.
By what factor does the unique average reaction rate change if the coefficients in the chemical equation are doubled?
Can someone explain this relationship between the unique average rate and the chemical equation. Thank you.
Sat Feb 21, 2015 1:00 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Homework 13.11(a) Why do we reverse the anode reaction?
Replies: 3
Views: 776

### Re: Homework 13.11(a) Why do we reverse the anode reaction?

Sorry my question was not clear. I was asking why we would have to reverse the half reaction Ni^2+(aq) + 2e^- →Ni(s)

Fri Feb 13, 2015 12:40 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Homework 13.11(a) Why do we reverse the anode reaction?
Replies: 3
Views: 776

### Homework 13.11(a) Why do we reverse the anode reaction?

Write the half-reactions of the balanced equation for the cell reaction for each of the following galvanic cells:
a.) Ni(s)|Ni2+(aq)||Ag+(aq)|Ag(s)

I understand how to obtain the half reactions, but why do we have to reverse the anode reaction?

Thank you!
Fri Feb 06, 2015 7:47 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Thinking Point Pg. 537. Value of K?
Replies: 1
Views: 356

### Thinking Point Pg. 537. Value of K?

Thinking Point: What is the value of K for a reaction that has Ecell = 0?

Can someone explain the concept behind this please?
Thank you!
Thu Feb 05, 2015 12:30 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Calculating The Energy Changes When Heating An Ideal Gas
Replies: 4
Views: 1899

### Re: Calculating The Energy Changes When Heating An Ideal Gas

Hi Vivien,
In this problem we are not given the final temperature and we need to know the final temperature in order to find the change in temperature and then solve for delta U.
That is why the first step is to find delta T so then we can plug it in to the delta U=q equation.

I hope this helps.
Thu Jan 29, 2015 11:46 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Self Test 8.3B: Why do we not Include n in our Calculation?
Replies: 1
Views: 592

### Self Test 8.3B: Why do we not Include n in our Calculation?

Self Test 8.3B: Calculate change in molar entropy of carbon dioxide that is allowed to expand isothermally to 10. times its initial volume (treat carbon dioxide as an ideal gas).
For this problem why don't we include the moles of carbon dioxide in our calculation?

Thank you!
Thu Jan 29, 2015 10:22 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sel Test 7.9A How do we calculate H(vapor)?
Replies: 4
Views: 1668

### Re: Sel Test 7.9A How do we calculate H(vapor)?

Hi Justin,
Sorry for the late reply. No I was asking how to solve Delta Hvap .
Fri Jan 23, 2015 10:20 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 7.9 change in internal energy
Replies: 3
Views: 729

### Re: 7.9 change in internal energy

For the pressure, how do we convert torr to atm?
In the solutions manual they divided 750torr by 760 torr x atm^-1 But how do we know it is 760, is that given to us or do we just have to know it? I cannot find it in the equation sheet.
Wed Jan 21, 2015 11:18 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sel Test 7.9A How do we calculate H(vapor)?
Replies: 4
Views: 1668

### Re: Sel Test 7.9A How do we calculate H(vapor)?

Okay that makes sense.
So for this type of question we do not have to do use Delta H=Hm(vapor)- Hm(Liquid)? How would we know when to use this equation?
Wed Jan 21, 2015 6:00 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sel Test 7.9A How do we calculate H(vapor)?
Replies: 4
Views: 1668

### Sel Test 7.9A How do we calculate H(vapor)?

A sample of benzene, C6H6, was heated to 80 degrees Celsius, its normal boiling point. The heating was continued until 15.4 kJ had been supplied; as a result, 39.1g of boiling benzene was vaporized. What is the enthalpy of vaporization of benzene at its boiling point? For this problem I understand t...
Sun Jan 18, 2015 10:38 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Self Test 7.6A How do we Find the Original Volume?
Replies: 4
Views: 894

### Self Test 7.6A How do we Find the Original Volume?

Suppose that 2.00mol CO2 at 2.00atm and 300.K is compressed isothermally and reversibly to half its original volume before being used to produce soda water. Calculate w, q, and delta U by treating the CO2 as an ideal gas. I am confused on how to find the original volume to solve for w. Or do we not ...
Fri Jan 09, 2015 6:31 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Thinking Point page 240
Replies: 2
Views: 612

### Thinking Point page 240

Thinking Point: How could you ensure that an electric battery produced and electric current reversibly?

Can someone help me understand this please. Thank you!
Fri Dec 12, 2014 4:18 pm
Forum: Lewis Acids & Bases
Topic: HW Question 11.17
Replies: 3
Views: 650

### Re: HW Question 11.17

Hi,
So no matter the resonance structure, SO2 will always be an acid?
Mon Dec 08, 2014 1:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Do we need to convert from atm to bar?
Replies: 1
Views: 408

### Do we need to convert from atm to bar?

Hi,
When we are calculating equilibrium partial pressures and the information we are given is in atm, do we have to convert to bar showing our work? or can we just leave it in atm units?

Thank you!
Mon Dec 01, 2014 4:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate Question
Replies: 5
Views: 770

### Re: Polydentate Question

Yes, because of this bent geometry that water has, ONLY one lone pair has the correct orientation to bond, so its Monodentate.

Hope this helps.
Sun Nov 30, 2014 3:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate Question
Replies: 5
Views: 770

### Re: Polydentate Question

Hi,
Yes, the best way would be to draw the Lewis structure first and see if there are any lone pairs, then determine whether it is a polydentate or not.

I hope this helps!
Tue Nov 11, 2014 8:08 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Textbook Pg. 120 Thinking Point Question
Replies: 1
Views: 368

### Textbook Pg. 120 Thinking Point Question

Can someone help me with this question, its on page 120 in the textbook.

Can you use the molecular orbital theory to explain why fluorine is such a highly reactive gas?

Thank you.
Mon Nov 03, 2014 11:31 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Character and Covalent Character
Replies: 4
Views: 1315

### Ionic Character and Covalent Character

Can someone explain what ionic and covalent character is? And what is the difference between them?

Thank you!
Mon Nov 03, 2014 12:09 am
Forum: Dipole Moments
Topic: Dipole Moment Arrows
Replies: 5
Views: 1666

### Re: Dipole Moment Arrows

Hi, I agree, I think that the direction of the arrow does change. In the textbook on page 77 it says that: The original, "old," is when the arrow points towards the negative charge. In the modern convention, the arrow points towards the positive charge. Lauren, I am not sure why this chang...
Sun Nov 02, 2014 11:43 pm
Forum: Ionic & Covalent Bonds
Topic: Problem 2.19
Replies: 1
Views: 1943

### Problem 2.19

Give the ground-state configuration and number of unpaired electrons expected for each of the following ions:

For this question, I am just confused on how do we know the expected unpaired electrons.
a.) Sb3+
b.) Sn4+
Wed Oct 22, 2014 11:55 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation
Replies: 3
Views: 491

### Re: Rydberg Equation

Hi,
For this equation n1 refers to the final energy level. Remember that for these kinds of problems it will always be: Final-Initial, so 1/n1- 1/n2.

Hope this helps!
Tue Oct 21, 2014 11:33 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Hw Problem 1.85 D
Replies: 1
Views: 335

### Hw Problem 1.85 D

85D: Give the notation for the valance- shell configuration (including the outermost d-electrons) of d.) "coinage" metals (Cu, Ag, Au).

Can someone explain this question. I do not understand why we have the "(n-1)" in the answer.

Thank you!
Thu Oct 16, 2014 11:39 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Absorption/emission spectroscopy
Replies: 1
Views: 428

### Re: Absorption/emission spectroscopy

Hi Casey, To my understanding, they are two different things because the atomic absorption spectrum refers to the radiation that is being absorbed and the emission spectrum refers to the radiation that is being ejected. However, the absorption lines and emitted lines do have the same frequency. I ho...
Tue Oct 07, 2014 9:56 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.5
Replies: 2
Views: 649

### Re: G.5

Okay that makes sense. Thank you so much Nima!
Tue Oct 07, 2014 9:07 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.5
Replies: 2
Views: 649

### G.5

G.5: You need to prepare 510.g of an aqueous solution containing 5.45% K2NO3 by mass. Describe how you would prepare the solution and what mass of each component you would use. For this problem I am just confused on why we have to multiply 510g with 5.45% to obtain the mass of K2NO3. Can someone exp...