Chemistry - May 2007

A Leclanché dry cell is an example of a galvanic cell whose voltage will drop with time. This decrease is related to a decrease in the value of Q in the Nerst equation for the dry cell. Would it be possible to design a battery that actually increased in voltage over time? Chemically, what would be required?

A. yes, by using metals that began with a larger difference in reduction potentials

B. yes, by using reactions whose equilibrium will shift toward formation of reactants with time, the value of Q will decrease and the voltage will increase when Q falls below 1.

C. yes, by using reactions whose equilibrium will shift toward formation of products with time, the value of Q will increase and the voltage will increase as Q rises aove 1.

D. no. It is not even theoretically possible that a battery could increase in voltage over time

2007-05-02 11:11:34 · 1 answers · asked by rnjes21 2

How long must a 2.00 ampere current flow to liberate 3.00 liters of oxygen measured at 27degrees celcius and 2.00 atmospheres of pressure from a solution of dilute sulfuric acid.

Answer is Seconds

2007-05-02 11:05:58 · 2 answers · asked by Anonymous

a. A gamma ray (γ) radiation reaction is the most energetic of electromagnetic radiation reactions

b. Gamma particles have no mass or charge.

c. Electrons can also be captured by a parent atom to form a new element.

2007-05-02 10:59:00 · 5 answers · asked by rnjes21 2

2007-05-02 10:51:59 · 1 answers · asked by Anonymous

acid or base is added to the buffer?

2007-05-02 10:25:50 · 1 answers · asked by darkraven_222000 1

A certain compound can be used to synthesize both 2-chlorobutane and 1,2-dichlorobutane in one step. What are the equations for the two reactions?

and:

Two different reactants can be used to produce 2-bromopentene. What are the equations that show how each of these reactants can can produce this product?

thank you very much.

2007-05-02 10:21:19 · 1 answers · asked by Anonymous

Is AsH3 a tetrahedron or a trigonal pyramid??
It is AX3E, which my book says is a trigonal pyramid, but then the notes my professor gave me says it's a tetrahedron.. I'm so confused..

2007-05-02 10:14:27 · 2 answers · asked by Anonymous

2007-05-02 09:34:32 · 2 answers · asked by Anonymous

Find the molecular weight of a gas of which 5.03 g occupies a volume of 4.4L when the pressure is 1.333 atm and the temperature 65.5 degrees Celcius.

2007-05-02 09:20:38 · 3 answers · asked by georgie0515 1

A Rolaids tablet contains calcium carbonate, which neutralizes stomach acid. If 30.10ml of 0.448M hydrochloric acid is required to neutralize one tablet, how many milligrams of calcium carbonate are in a Rolaids tablet?

2007-05-02 09:18:58 · 1 answers · asked by Lisa 1

A. KS
B. K2S
C. KS2 or
D. K2S2?

2007-05-02 09:18:56 · 3 answers · asked by 062419844142436830 1

need help for a science project and i dont understand it.

2007-05-02 09:03:45 · 3 answers · asked by Anonymous

can anyone help me write out the balanced chemical equation using these four species: Co(H2O)6^2+ , CoCl4^2-, Cl- , and H2O. Explain how you determined the equation. also. How do i know if the reaction is written endothermic or exothermic? im getting really confused. thanks.

2007-05-02 08:56:45 · 2 answers · asked by Anonymous

2007-05-02 08:41:08 · 7 answers · asked by babymae29x 1

the question goes:

"The depletion of ozone, O3, in the atmosphere takes place through a series of elementary steps.

1) NO(g) + O3(g) --> NO2 (g) + O2(g) (fast)
2) NO2(g) --> NO(g) + O(g) (slow)
3) O(g) + O3(g) --> 2O2(g) (fast)

a) What is the catalyst in this reaction?
b) Is the catalyst heterogeneous or homogeneous?"


Can anyone tell me how to find the catalyst in this reaction and how to tell whether its **** or heterogeneous? please be specific or detailistic if possible . thank you

2007-05-02 08:31:23 · 2 answers · asked by Anonymous

A 50.00 mL mixture of H3PO4 and NaH2PO4 is titrated with 0.1050M NaOH. The first end point occurs at 5.07mL and the second end point occurs at 35.25mL.
a) what's the molarity of H3PO4
b) what's the molarity of NaH2PO4
c) what is the w/v% H3PO4

I need to know how this is done for a test please. thanks!

2007-05-02 08:30:50 · 1 answers · asked by slicksingh2k 2

is propane gas a compound or an element?

2007-05-02 08:28:47 · 12 answers · asked by princess 2

2007-05-02 08:26:18 · 1 answers · asked by Anonymous

This is the problem that I got on my homework:

Acetylcholine esterase, 3.0 mg, was dissolved in 10.0 mL solution. From this solution, 0.60 mL was added to the sample tube, bringing the volume to a total of 3.0 mL. How many mg of acetylcholine esterase did you have in the sample tube?

2007-05-02 08:20:01 · 3 answers · asked by Anonymous

I went on vacation for about 6 weeks and when I came back, my Irish Spring "waterfall" bar of soap lost its smell totally. It just smelled like nothing. No fresh clean scent anymore! I'm wondering if anyone knows about this.

2007-05-02 07:33:45 · 8 answers · asked by bingo8900 2

What is meant by doubly ionized lithium as relates to it's atomic number?

2007-05-02 07:22:39 · 2 answers · asked by Anonymous

E for cell reaction is -0.89?

2007-05-02 06:08:28 · 4 answers · asked by dasdaner 1

2007-05-02 06:01:18 · 5 answers · asked by Anonymous

dry ice does not have a normal boiling point under normal atmospheric conditions, even though carbon dioxide is a liquid in fire extinguishers.

2007-05-02 05:28:26 · 3 answers · asked by Anonymous

I was arguing with someone over global warming and they said something about how "biological CO2" is absorbed by the plants and oceans. I was not aware that there was a distinction between "biological" and "artificial" CO2. I always thought CO2 was CO2, because it is always the same elemental composition. I'm aware that plants take in CO2 to make oxygen (this includes phytoplankton). Perhaps other gases are released into the air from burning fossil fuels, but as far as I'm concerned, CO2 is the main "culprit of global warming." I don't necessarily believe that CO2 levels in the atmosphere are the sole case, or even a significant accelerator, of global warming. However, I need to be able to provide a well researched counter argument against any of his claims and, well, any help counts.

2007-05-02 05:01:13 · 5 answers · asked by Anonymous

2007-05-02 05:00:32 · 2 answers · asked by Raigaanah A 1

2007-05-02 04:59:18 · 1 answers · asked by Raigaanah A 1

2007-05-02 04:58:42 · 8 answers · asked by kkaroub 1

2007-05-02 04:29:19 · 5 answers · asked by kkaroub 1

1. Why Sulfuric acid, H2SO4 is more oxidizer than Sulphurous acid H2SO3

2. Explain oxidation and reduction traits of the element N (nitrogen) in these cases:
N (oxidation number -3)
N (oxidation number 0)
N (oxidation number +5)

please help.....

2007-05-02 04:10:04 · 2 answers · asked by eri 1