Chemistry - March 2007

Using a table of standard reduction potentials calculate the standard cell potential (electromotive force) in volts

for the following cell.


Cu + Cl2 = Cu2+ + 2Cl−

Calculate the standard free energy change in kJ/mol for the above cell reaction.

2007-03-29 17:14:19 · 1 answers · asked by Anonymous

What volume of 6.00 M sodium hydroxide in milliliters must be diluted to 249.0 mL to make a 1.50 M solution of sodium hydroxide?

2007-03-29 17:02:42 · 2 answers · asked by Anonymous

1) A beaker contains a sample of 0.5 mole of potassium bromide ,KBr.
a)Find the number of formula units of KBr in the beaker.
b)Calculate the total number of ions present in the beaker.

2)How many chloride ions in 0.5 moles of magnesium chloride, MgCl2

2007-03-29 16:53:39 · 1 answers · asked by kluivert(17) 4

when does an atom become a postive ion? when does an atom become a negative ion?

2007-03-29 16:48:59 · 7 answers · asked by Anonymous

You're given the eqn 3O2 + 2N2O <--> 4NO2
You're also given .016 mol O2 and .082 mol N2O in a 1 Liter vessel. They react to form NO2. At equilibirum, the concetration for NO2 was .015 M.

Find the equlibirum constant?

I did the ICE thing..
3O2 + 2N2O <--> 4NO2
initial: .016 M .082 M 0 M
change: -3x -2x +4x
@equilibrum: ___ ___ .015 M
x = .00375 right?
So what the heck do you do after?...

Because the answer apparently is K = 85.

2007-03-29 16:42:30 · 1 answers · asked by romantic 3

a. Babituric acid, HC4H3N2O3, is used to prepare barbiturates, a class of drugs used as sedatives. A 325 mL aqueous solution of barbituric acid has a pH of 2.34 and contains 9 g of the acid. What is the Ka for barbituric acid?

b.Penicillin (MM = 356 g/mol), an antibiotic often used to treat bacterial infections, is a weak acid. Its Ka is 1.7 x 10^-3. Calculate [H+] in solutions prepared by adding enough water to following to make 725 mL.

Please show and explain work.

2007-03-29 16:37:06 · 1 answers · asked by nirmal 1

Calculate the value of the equilibrium constant, Keq , for the following reaction at 298 Kelvin.
(Use the reaction free energy given below.)


2NO + O2 = 2NO2 in the gaseous state


ΔGo = −55.6 kJ/mol

IT IS NOT 1.02.

2007-03-29 16:28:34 · 2 answers · asked by Kos 1

2007-03-29 16:20:01 · 7 answers · asked by buckniv 1

5.The normal respiratory rate for a human being is 15.0 breaths per minute. The average volume of air for each breath is 505 cm ex3 at 20.0*C and 9.95 x 10 ex4 Pa. What is the volume of air at STP that an individual breathes in one day? Give your answer in cubic meters.

2007-03-29 16:18:24 · 3 answers · asked by <ChemStudent> 1

a. Babituric acid, HC4H3N2O3, is used to prepare barbiturates, a class of drugs used as sedatives. A 325 mL aqueous solution of barbituric acid has a pH of 2.34 and contains 9 g of the acid. What is the Ka for barbituric acid?

b.Penicillin (MM = 356 g/mol), an antibiotic often used to treat bacterial infections, is a weak acid. Its Ka is 1.7 x 10^-3. Calculate [H+] in solutions prepared by adding enough water to following to make 1.30 L.

2007-03-29 16:13:02 · 2 answers · asked by Anonymous

what is the sum of the coefficients?

2007-03-29 16:07:26 · 3 answers · asked by trina o 1

this is for chemistry
i need help ASAP!!!! please im desperate im begging anyone to help me.... my whole school career is riding on this

2007-03-29 15:54:21 · 2 answers · asked by roxy 1

What volume of O2 (m3) is needed for the complete combustion of 155 g of C3H8 at 19.0oC and 100.0 kPa

2007-03-29 15:46:48 · 2 answers · asked by owen 1

what does it mean when the chemical is an aqueous chemical?

2007-03-29 15:43:34 · 2 answers · asked by infamous_amour 2

for the evaporation of liquid water predict wheter the entropy change would be positive, negative or zero. (must write the equation for the process)

2007-03-29 15:33:49 · 2 answers · asked by michiusa 1

If one shell in an element isn't full why are electrons in the next shell?

2007-03-29 15:03:45 · 2 answers · asked by Nick 1

2007-03-29 14:36:36 · 1 answers · asked by tony b 1

and why is this reaction important??
thanks in advance..
4Fe + 3O(2) = 2Fe(2)O

2007-03-29 14:00:01 · 3 answers · asked by katracho4 4

Neodymium is element # 60, and I am haqving trouble finding this out, also if you know the electon configuration, that would be great :)

2007-03-29 13:56:33 · 3 answers · asked by Anonymous

Could you please give me a simple definition/explanation of a solution equilibrium? Can it exist in a supersaturated solution?
Thank you.

2007-03-29 13:51:50 · 0 answers · asked by jade832 2

All purpose flour it has a knight on the bag I need the formula. In water the formula is H2O, 2 hydrogens and an oxygen. I've looked on wiki and searched in other places and couldn't find it please help!

2007-03-29 13:50:00 · 3 answers · asked by darkflower366 5

How would I round 1097.25 to only 3 sig figs?

2007-03-29 13:48:24 · 3 answers · asked by NightKast 1

The below reactions are followed by one or two statements. Choose the correct statements that follow each reaction.

HNO3 + H2O ↔ NO3− + H3O+
a) This is an example of an elimination reaction

Pb2+(aq) + 2I−(aq) → PbI2(s)
b) This is an example of a precipitation reaction
c) The product is an ionic compound

CH3CH2Br + OH- → CH3CH2OH + Br- d) This is an example of a elimination reaction
e) Double bonds are formed in the product

2007-03-29 13:46:27 · 1 answers · asked by Anonymous

Prove ( by forming appropriate ratios) that the following four oxides of sulfur obey the Law of Multiple Proportions. There are a total of six seperate and distinct ratios taht can be formed from this data. This does not include any inverses of these ratios.

S2O
SO2
S2O3
SO3

2007-03-29 13:42:16 · 1 answers · asked by Anonymous

I need a name for a stuffed mole for chemistry?
For this project, my class has to make stuffed moles and name them something that has "mole in the title"
For example:

"Mole"opoly Man, like monopoly

The "Mole"sen Twins, like Olsen

Ca"Mole", like camo, for camoflouge

Any ideas????

My teacher is not tricking me...this assingment is given every year....it's just kind of a fun little thing to do.
:)

The cheesier the name, the better!

2007-03-29 13:40:39 · 8 answers · asked by gabster 2

Which of the following are true statements ?
a) Volatiltiy of a liquid decreases with increasing temperature
b) The equilibrium vapor pressure of a liquid results from equal rates of evaporation and condensation
c) The equilibrium vapor pressure of a liquid remains constant as temperature changes
d) The vapor pressure of a liquid at its normal boiling point is strongly affected by the type
of molecules the liquid consists of

2007-03-29 13:10:49 · 1 answers · asked by Anonymous

What might be a possible explanation?

2007-03-29 12:57:40 · 4 answers · asked by airjames023 1

how much heat would be required to convert 10 grams of ice at 0 degree celcius to 10 gram of water at 75 degree celcius.The following values may be use to you:
Specific heat of water=1 cal/g -degree celcius
Heat of vaporization of water=540 cal/g
Heat of fusion of water = 80 cal/g

2007-03-29 12:53:43 · 1 answers · asked by Blesson 2

a sample of nitrogen gas has a volume of 1.75L at STP. how many moles of N2 are present?

please help!!

2007-03-29 12:53:03 · 2 answers · asked by katieklovesga 1

2007-03-29 12:50:47 · 5 answers · asked by Dom 2