Chemistry - January 2007

2007-01-31 07:03:13 · 6 answers · asked by scoobydoolovely 1

How would you compute the heat change for the reaction of 1.24 grams of NO according to the following equation?

2NO + O2 → 2NO2 +114.14 kJ

2007-01-31 06:48:16 · 1 answers · asked by San Fran Kid 2

The dissolution of NH4ClO4 in H2O is endothermic.
DeltaH for the solution is 33.5 KJ/mol.
If you prepare a 1.00m solution of NH4ClO4, with the water beginning at 25C, what is the final temperature of the solution?
Note: Assume that the specific heats of pure water and the solution are the same, 4.18 j (k*g).

2007-01-31 06:34:24 · 2 answers · asked by Anonymous

2007-01-31 06:23:33 · 6 answers · asked by jo_trek1 1

Chlorine is prepared industrially by passing an electric current through brine, a concentrated solution of sodium chloride.
2NaCl + 2H2O → 2NaOH + Cl2 +H2
All three products are commercially valuable. If 1500 g of a brine solution that is 24% NaCl by mass is used, how many grams of each product can be produced?

2007-01-31 06:20:24 · 2 answers · asked by San Fran Kid 2

2007-01-31 06:14:10 · 1 answers · asked by Wennie 1

2007-01-31 06:13:11 · 2 answers · asked by Wennie 1

How much energy (in kilojoules) is released when 15.3 g of steam at 115C is condensed to give liquid water at 75C? The heat of vaporization of liquid water is 40.67 kJ/mol, and the molar heat capacity is 75.3 J/ (k*mol) for the liquid and 33.6 J / (k*mol) for the vapor.

I don't get this at all!!

2007-01-31 06:10:45 · 2 answers · asked by samaireh d 1

Calcium chloride is used to melt ice or to keep it from forming on roads. This important compound can be produced by reacting calcium carbonate with hydrochloric acid. Two by-products are water and carbon dioxide. What would the balanced equation for the formation of calcium chloride by this reaction be?

2007-01-31 05:43:01 · 2 answers · asked by San Fran Kid 2

A 0.250 L solution of 1.150 M hydrochloric acid is used to neutralize a 45.0 g sample of barium hydroxide in a coffe-cup calorimeter. Barium chloride, a chemical that is sometimes used to produce a bright green color in fireworks, is produced by the reaction. The temp. in the calorimeter was observed to rise from 20.0 C to 32.9 C during the course of the neutralization. Assume that the density of the hydrochloric acid solution is 1.00 g/mL and that the specific heat capacity of the system is the same as that for water, 4.18 J/(g*K). Assume that only water is available to absorb or release heat and that the reaction is at a constant pressure.
2HCl(aq)+Ba(OH)2(aq)-->BaCl2(aq)+2H2O(l)

1.What was the limiting reagent in the neutralization reaction? Provide support for your answer.

2. How many moles of excess reagent were left over?

3. If 27.3g of barium chloride were obtained after the neutralization was complete, what was the percent yield?

2007-01-31 05:42:15 · 1 answers · asked by Tracey Lee ♥ 2

(Consider the directing effects of the ester and the first nitro group on the addition of the second nitro group).

2007-01-31 05:27:04 · 4 answers · asked by webogirl 2

how does ionization energy change as one proceeds accross the periodic table and how does it change as you move donw the periodic table?

2007-01-31 05:26:56 · 3 answers · asked by cutie pie! 3

1- A flask contains 25.0 mL of diethyl ether weighing 17.84g.What's the density of ether?

2- What's the mass of 22.7mL sample of gasoline, whose density is 0.70g/cm^3?

3- The acidic constituent in vinegar is acetic acid. A 10.0mL sample of a certain vinegar contains 501mg of acetic acid.Whats the Mass of acetic acid expressed in micrograms?

4- A water molecule has 2 hydrogen atoms,each connected to an oxygen atom.The distance between any one hydrogen atom & the oxygen atom is 0.96 Angstroms.Whats the distance in millimeters?
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Is the formula for Mass: M= V x D?Because that's what my answers are based on.
1- Idk if I'm doing this right but I got:7.13 g/mL

2- I actually got 15.89 but using the correct amount of Significant Figures, I think I should end up with 15.

3- ? I'm trying to work it out now.
4- ? I'm trying to work this one out as well.

IDK if I'm doing these right.Can you please check what I'm doing & possibly explain the other ones to me.Thank You! = )

2007-01-31 05:21:54 · 3 answers · asked by Miss*Curious 5

2007-01-31 05:20:15 · 2 answers · asked by webogirl 2

2007-01-31 04:54:57 · 1 answers · asked by zizi m 1

2007-01-31 04:17:40 · 2 answers · asked by Anonymous

2007-01-31 04:01:59 · 8 answers · asked by torirowe 2

If you can help me with any of these, that would be great. Thanks.

During the fermentation process, why is it IMPOSSIBLE to get a soln with an Ethanol concentration of greater than 10-15% without using distillation?

Why is it possible to seperate and concentrate ethanol in the mixture during distillation?

WHY does alcohol turn into vinegar if it sits too long?

And why is ethanol dangerous or toxic to humans?

2007-01-31 04:00:33 · 2 answers · asked by Angel Eve 6

2007-01-31 03:45:58 · 6 answers · asked by Kimmy D 1

COOHCL2 OR COOHCL4?

2007-01-31 03:36:45 · 14 answers · asked by Kimmy D 1

2007-01-31 03:34:28 · 4 answers · asked by paperboi 2

2007-01-31 03:29:37 · 2 answers · asked by Paola 1

2007-01-31 03:25:35 · 1 answers · asked by Paola 1

You have two coloress molecular liquids, one boiling at -84C and other at 34 C both at atmospheric pressure.

Which of the following statement is correct? Correct those that are not.

1). The higher-boiling liquid has greater intermolecular forces than the other.

2) the lower boiling liquid must consist of nonpolar molecules.

3) the lower boiling liquid has lower molecular weight than the higher boiling liquid

4) the two liquids have identical vapor pressure at their normal boiling points

2007-01-31 03:16:50 · 3 answers · asked by Anonymous

A sample of oxygen gas occupies 320.0 mL at 27ºC and atmospheric pressure. What volume does it occupy at 120ºC and the same pressure?

2007-01-31 03:14:44 · 3 answers · asked by MEB 2

2007-01-31 03:09:19 · 9 answers · asked by Anonymous

Ethylene glycol (HOCH2CH2OH), the major substance in anitfreeze, has normal boiling point of 198 C. By comparison, ethyl alcohol (CH3CH2OH) boils @ 78 degree C at atmospheric pressure. ethelyne glycol dimethyl ether (CH3OCH2CH2OCH3) has a normal boiling point of 83C & ethyl methyl ether (CH3CH2OCH3) has a normal b.p of 11C.

Question: 1) explain why replacement of a hydrogen on the oxygen by CH3 generally results in a lower b.p.


2) What are the major factors responsible for the difference in b.p . of the two ethers?

Please help lost.

2007-01-31 02:54:30 · 5 answers · asked by Anonymous

2007-01-31 02:48:45 · 1 answers · asked by torirowe 2

2007-01-31 02:38:46 · 1 answers · asked by Anonymous

A 125.0 mL sample of nitrogen at 790 torr was compressed to a volume of 75.0 mL in a syringe. What was the pressure of trapped nitrogen in torr?

can someone give me the formula so I can figure this out???

2007-01-31 02:26:36 · 5 answers · asked by MEB 2