Science & Mathematics - 9 December 2007

Calculate the E°cell for the reaction below,
Tl+(aq) + 2 Cl-(aq) → 2 Tl(s) + Cl2(g)

given the following standard reduction potentials.

Cl2(g) + 2 e- → 2 Cl-(aq) E° = +1.36 V
Tl+(aq) + e- → Tl(s) E° = -0.34 V

a.-2.04 V
b.+1.70 V
c.+2.04 V
d.1.02 V
e.-1.70 V

2007-12-09 06:46:29 · 1 answers · asked by Anonymous in Chemistry

-5^2

I'm not sure if it's -25 or 25, but my calculator says -25 but when i did the process of (-5)(-5) and it turns out to be 25, so idk if it's the positive or negative one =/

2007-12-09 06:43:40 · 2 answers · asked by hpdc90 1 in Mathematics

At time t=0 a grinding wheel has an angular velocity of 26.0 rad/s. It has a constant angular acceleration of 34.0 rad/s^2 until a circuit breaker trips at time t = 2.30 s. From then on, the wheel turns through an angle of 432 rad as it coasts to a stop at constant angular deceleration

a)Through what total angle did the wheel turn between t=0 and the time it stopped?
Express your answer in radians.

b)At what time does the wheel stop?
Express your answer in seconds.


c)What was the wheel's angular acceleration as it slowed down?
Express your answer in radians per second per second.

2007-12-09 06:41:33 · 1 answers · asked by cglrtk 1 in Physics

The difference between the third and fourth ionization energies of scandium is much larger than the difference between the third and fourth ionization for titanuim. Why???

2007-12-09 06:37:31 · 2 answers · asked by John 3 in Chemistry

In the following reaction,

2 Fe3+(aq) + Zn(s) → 2 Fe2+(aq) + Zn2+(aq)

a.Zn(s) is the reducing agent and Fe2+(aq) is the oxidizing agent.

b.Zn(s) is the reducing agent and Zn2+(aq) is the oxidizing agent.

c.Fe3+(aq) is the reducing agent and Zn(s) is the oxidizing agent.

d.Zn(s) is the reducing agent and Fe3+(aq) is the oxidizing agent.

e.Fe3+(aq) is the reducing agent and Fe2+(aq) is the oxidizing agent.

2007-12-09 06:36:44 · 4 answers · asked by Anonymous in Chemistry

2007-12-09 06:35:49 · 3 answers · asked by Anonymous in Geography

I remember when the Viking missions landed on Mars in the mid 70's, there were reports in the media that one of its experiments had found life on Mars.

Does anyone know what this was all about? Was the experiment wrong, or were the results misinterpreted?

2007-12-09 06:35:13 · 6 answers · asked by footynutguy 4 in Astronomy & Space

2007-12-09 06:34:28 · 18 answers · asked by Anonymous in Physics

A right circular cylinder is to be designed to hold 20 cubic inches of soft drink. The cost of the material for the top and bottom of the can is twice the cost of the material of the sides. Let r represent the radius and h the height of the cylinder. a.) Write the equation for the surface area SA in terms or r and h. b.) Write the cost function C. c.) Write the cost function as a function of one variable, r. d.) Find the radius that minimizes cost. Thank you, I'm really confused on these minimization/ max problems. Please explain each step.

2007-12-09 06:33:59 · 1 answers · asked by cason90 1 in Mathematics

In which of the following substances is hydrogen bonding likely to play an important role in determining physical properties and why: Methane (Ch4), Hydrazine(H2NNH2), Methyl Fluoride (Ch3F) or Hydrogen Sulfide(H2S) ?? And why??

Thanks in advance

2007-12-09 06:30:43 · 2 answers · asked by John 3 in Chemistry

In which of the following statements is the functional group correctly identifed for the given compound ?


a) CH3CH2CH2COH ether


b) H3CCOCH3 ketone


c) CH3COOCH2CH3 ketone


d) C6H5CN nitrile

there can be more than one correct answer

2007-12-09 06:30:35 · 1 answers · asked by Anonymous in Chemistry

for my algebra and trig class

2007-12-09 06:30:15 · 4 answers · asked by clawznpawz89 1 in Mathematics

Please, Show steps. (I am trying to firgure out what I am doing wrong). Thanks

2007-12-09 06:29:19 · 6 answers · asked by Sam Dali 2 in Mathematics

It has gone into the floor boards. How can I remove it or what can I use on the wood to neutralise it? I think it leaked as a vapour rather than a spillage.

2007-12-09 06:28:38 · 3 answers · asked by Anonymous in Chemistry

I must be way behind in math and need to bone up.

2007-12-09 06:26:44 · 7 answers · asked by Neomaxizoomedweebie 3 in Mathematics

2007-12-09 06:25:35 · 4 answers · asked by Anonymous in Botany

25.0 mL of 0.10 M iron (III) nitrate with excess sodium hydroxide?

2007-12-09 06:22:46 · 3 answers · asked by Blah 1 in Chemistry

2007-12-09 06:21:04 · 4 answers · asked by suzii jane 1 in Mathematics

ln (x/e^x)

2007-12-09 06:21:01 · 5 answers · asked by Anonymous in Mathematics

The bird perched on the swing shown below has a mass of 40.9 g, and the base of the swing, y = 7.87 cm below the hook, has a mass of 155 g. The swing and bird are originally at rest, and then the bird takes off horizontally at 2.02 m/s. How high will the base of the swing rise above its original level? Disregard friction.

2007-12-09 06:19:38 · 3 answers · asked by andyjumpman23 3 in Physics

With zero gravity, and space as we know it being a vacuum, what would have caused the big bang? Can any scientist on earth take (nothing) and cause it to explode? If and when that scientist does, would he not, then call his amazing feat, an act of intellegent design? I do believe in possibility of big bang. However, common sense tells us all, that, Such a huge explosion would caused chaos, not perfect harmony in our universe. Humans, no matter how smart he or she will tell you that they are, cannot make life from nothing. How logical is it
to believe it happened by accident?

2007-12-09 06:19:03 · 16 answers · asked by steelbill77 1 in Astronomy & Space

22) The Second Law of Thermodynamics states that in spontaneous reactions, the universe tends toward a state of greater disorder. When the entropy increase in the system is greater than the entropy decrese in the surroundings, the entropy of the universe will increase.
A) a release of heat by the system
B) an absorption of heat by the system
C) an increase in disorder in the system
D) a decrease in randomness in the system
E) none of the above

16) A 73 g sample of water with a temperature of 5.3°C is added to 271 g water at 59°C in an insulated container. What is the final temperature after thermal equilibrium is reached?
A) 0.021°C
B) 17°C
C) 32°C
D) 48°C
E) 224°C

2007-12-09 06:18:48 · 1 answers · asked by lyudmila y 1 in Chemistry

(1+sec x)/(tan x+sin x)=csc x

2007-12-09 06:17:58 · 1 answers · asked by eman k 1 in Mathematics

2007-12-09 06:12:17 · 7 answers · asked by Anonymous in Biology

1.) can work be negative? (i.e. if you go up 1 flight of stairs (10m) and then go back done net work is 0?)
2.) If the work done on an object doubles its kinetic energy, does it double its velocity? If not, by what ratio does it change the velocity?- is the answer 1/4?

2007-12-09 06:11:39 · 2 answers · asked by Work Hard, Make Money, Enjoy Life... 3 in Physics

Hi can someone please help me with some similarities and some differences between San Le's periodic table and the normal periodic table?

2007-12-09 06:09:51 · 1 answers · asked by kyle v 1 in Chemistry

Why is it desirable to store sand(use to make concrete) in a moist conditions?

2007-12-09 06:08:27 · 3 answers · asked by duo_poon 2 in Engineering

Bicyclist has a tangential speed of 13.5m/s. Radius is 48.9 m. magnitude of force maintaing motion is 380 N. What is combined mass? Help please

2007-12-09 06:07:42 · 2 answers · asked by allda_jedi8472 1 in Physics

What increase in the Celsius temperature will produce a 7.0% increase in the volume of a sample of gas originally at 25.0°C if the gas pressure is held constant?

2007-12-09 06:06:48 · 2 answers · asked by Donna L 3 in Chemistry

Two lasers each produce 6.00 mW beams. The beam of laser B is wider, having twice the cross-sectional area as the beam of laser A.

Which of the following statements about these two laser beams is correct? (THERE MAY BE MORE THAN ONE CORRECT CHOICE.)
A. Both of the beams have the same average power.
B. Beam A has twice the intensity of beam B.
C. Beam B has twice the intensity of beam A.
D. Both beams have the same intensity.

2007-12-09 06:03:46 · 2 answers · asked by ~Brigit~ 2 in Physics