Chemistry - March 2007

The reaction A(g)+B(g)-->C(g) + D(g) + 30 kcal has a foward activation energy of 20 kcal. What is the activation energy for the reverse reaction?

30, 20, 10, or 50 kcal

thank you!

2007-03-15 13:45:27 · 1 answers · asked by Devin 1

all i know is that a guy invented a formula that i don't know how to use i know his name starts with an A. i'm really worried that i don't understand it please help.

2007-03-15 13:36:32 · 13 answers · asked by Anonymous

Entropy of the reactants minus the entropy of the products, Entropy of the products minutes the entropy of the reactants, Heat content of the products minus the heat content of the reactants, or heat content of the reactants minus the heat content of the products?

2007-03-15 13:30:18 · 1 answers · asked by Anonymous

a. H2O
b. O2
c. H2SO4
d. C6H12O6(glucose)
e. CH3COOH(acetic acid)

2007-03-15 13:29:02 · 2 answers · asked by payal p 1

H2(g) + \i2(g) ---> H2o(I) + energy

is this reaction exothermic or endormic?

2007-03-15 13:26:30 · 2 answers · asked by Anonymous

i have a graph to do and im confused which one should be the x and y axis. There is the reaction time in seconds, and the concentration which is in Molar. which ones are my x and y???

2007-03-15 13:26:10 · 3 answers · asked by anikabot 2

If so, what type of reaction is this, and what are the structures of the carboxylic acid and amino alcohol used?

If someone could at least point me to a good site with pictures of the structures that would be great.

2007-03-15 13:25:43 · 5 answers · asked by kd0284 2

I need to separate the water out of a mixture of organics and water. To do this, I will be using a sodium hydroxide caustic. One of the components in this mixture is methanol, and I am wondering if, when the caustic is added, methanol would separate in the water phase or the organic phase. I know that, generally, neutral compounds (which methanol is), extract into the organic phase, but since both sodium hydroxide and methanol have a OH- ion, would a reaction occur? Does that mean that methanol would go into the water portion? Or does methanol actually extract into the organic phase?

2007-03-15 13:12:16 · 2 answers · asked by Anonymous

remember that (m/m)= grams solute(100)/grams solution

here's the problem:

Red wine vinegar is a 5% (m/m) aqueous acetic acid (CHsubscript3COOH) solution. The red wine vinegar solution has a density of 1.04 g/mL.
How many grams of water would be in a 500 mL bottle of red wine vinegar?

2007-03-15 13:12:13 · 2 answers · asked by Anonymous

What pressure is a person exerting on the floor if the person weighs 145 lbs and has shoes that contact the floor over a total area of 300. cm2?

2007-03-15 13:01:20 · 4 answers · asked by James 1

A student calculated the theoretical yield of barium sulfate in a precipitation experiment to be 1.311 g. When she filtered, dried, and weighed her precipitate, however, her yield was only 1.275 g. Calculate the student's percent yield.

2007-03-15 13:01:13 · 5 answers · asked by cookee456 1

My son is taking chemistry online and I have no idea how to do this. He has to separate 5 materials, iron, salt, saw dust, gelatin, and sand. I think I can figure out all but the gelatin and salt. Please help!!!! I am so lost!!! He also has to state the purpose for this along with the steps, and equipment used.

Thank you for any and all help!!!

2007-03-15 12:33:52 · 2 answers · asked by S Denise J 2

Given the following reaction, calculate the mass of oxygen gas that would be necessary to burn 0.0255 mol of hydrogen gas.

2007-03-15 12:30:02 · 4 answers · asked by cookee456 1

2007-03-15 12:29:20 · 3 answers · asked by Alexandra D 1

Ions and Ionic Bonds

2007-03-15 12:24:42 · 3 answers · asked by Anonymous

2007-03-15 12:12:20 · 3 answers · asked by tq 3

What is the tempature at which a substance changes from liquid to solid??? I need it in degrees c and f....Thanks!!

2007-03-15 12:05:51 · 4 answers · asked by Nikki the Vampire 1

How many moles of Cr^+3 would be reduced by the same amount of electricity that produces 25 g of silver from a solution of silver nitrate?

how do i go about doing this?
im kind of confused.

2007-03-15 11:59:56 · 1 answers · asked by Anonymous

A salt contains only barium and one of the halide ions. A 0.158 g sample of the salt was dissolved in water, and an excess of sulfuric acid was added to form barium sulfate, which was filtered, dried, and weighed. Its mass was found to be 0.124 g. What is the formula of the barium halide?

(I don't need or want an answer, just an explanation of how to do it.)

2007-03-15 11:52:40 · 1 answers · asked by Anonymous

hey!! i found
http://library.dialog.com/bluesheets/html/bl0304.html
for merck index online..

and i'm trying to find the common name for potassium hydroxide (KOH)

is it available on that site? and how do you find it?

thanks!!

2007-03-15 11:52:01 · 3 answers · asked by Anonymous

A compound contains only carbon, hydrogen, nitrogen, and oxygen. Combustion of 0.157g of the compound produced 0.213 g of CO2 and 0.0310 g H2O. In another experiment, it is found that 0.103 g of the compound produces 0.0230 g NH3. What is the empirical formula of the compound? HINT: Combustion involves reacting with excess O2. Assume that all the carbon ends up in CO2 and all the hydrogen ends up in H2O. Also assume that all the nitrogen ends up in the NH3 in the second experiment.

(I don't need or want an answer, just an explanation of how to do it.)

2007-03-15 11:48:42 · 1 answers · asked by Anonymous

2007-03-15 11:48:09 · 3 answers · asked by Anonymous

a)the strongest intermolecular forces are dipole-dipole

b)in an individual molecule, the bonds between H and Br are ion-dipole

c) this is a covalent compound

d) the intermolecular forces are relatively weak

Note: hydrogen bonds are a specific type of dipole-diplole interactions. Thus in the above question, dipole-dipole forces include hydrogen bonds. Please help, thank you.

2007-03-15 11:46:31 · 1 answers · asked by peterdk86 1

Which of the following statements about boiling points of molecular substances are correct ?



a) HF has a higher boiling point than CH4

b) For the boiling points of hydrogen compounds of Group 16
H2Te > H2Se > H2S > H2O

c) For the boiling points of hydrogen compounds of Group 17
HF > HI > HBr > HCl

d) For the boiling points of hydrogen compounds of Group 14
SnH4 > GeH4 > SiH4 > CH4


we can get more than 1 answer

2007-03-15 11:41:31 · 2 answers · asked by tobeever 1

A student has a glass coffee table in their dorm room that they want to stack some of their books on. However they are a little worried about how much pressure the table can withstand at any one point.

If the pile of books has a mass of 11.60 kg, a length of 33.02 cm, a width of 33.02 cm, and
a height of 25.45 cm, how much pressure (N/m2) must the table be able to withstand at any place
where the books are placed ?

2007-03-15 11:40:24 · 2 answers · asked by tobeever 1

This reaction..
Heating copper (II) sulfide in the presence of diatomic oxygen produces pure coper and sulfur dioxide gas.

Can someone please break it down so i can understand how you got the answear? Thanks in advance

2007-03-15 11:38:57 · 1 answers · asked by ceomillionman 1

What is the layer called in which one or more electrons orbit within the electron cloud? Please help me!

2007-03-15 11:28:13 · 1 answers · asked by Nikki the Vampire 1

I am doing a science project and i need to know how sugar disolves in hot water. Ive searched every wheres and nothing gives me the right answer.

2007-03-15 11:10:57 · 4 answers · asked by Brooke M 1

Predict the sign of the entropy change, ΔS˚ , for each of the following reactions.

A) Pb2+(aq) + 2Cl-(aq) -> PbCl2(s)
B) CaCO3(s) -> CaO(s) + CO2(g)
C) 2NH3(g) -> N2(g) + 3H2(g)
D) P4(g) + 5O2(g) -> P4O10(s)
E) C4H8(g) + 6O2(g) -> 4CO2(g) + 4H20(g)
F) I2(s) -> I2(g)

Which are positive and which are negative?

2007-03-15 11:07:29 · 1 answers · asked by Anonymous

Predict the electrical conductivity of lithium fluoride, carbon tetrachloride, SiC, and Mg in dissolved state?

2007-03-15 10:55:05 · 1 answers · asked by solomon d 1