Chemistry - August 2007

I'm not sure how to work out this problem.. or how to even set it up..


A sample of helium has a volume of 325 mL and a pressure of 655mm Hg. What will be the pressure if the helium is compressed to 125 mL (T constant)

2007-08-01 13:28:32 · 1 answers · asked by sweetgirl78228 2

2007-08-01 13:23:18 · 2 answers · asked by Anonymous

Question specifies at high temperatures also ... i believe its something like this :

Sb2O3(s) + C(s) --> _______ + _______
thanks for the help

2007-08-01 12:30:22 · 1 answers · asked by Anonymous

I believe it looks something like this:

BiBr3(s) + H2O(l) --> ____ + _____
thanks for your help ... need to balance it also :/

2007-08-01 12:11:50 · 1 answers · asked by Anonymous

Combustion of 10.68 mg of the compound yields 16.01 mg CO2 and 4.37 mg H2O. The molar mass of the compound is 176.1 g/mole. What are the empirical and molecular formulas of the compound

2007-08-01 11:58:07 · 5 answers · asked by Anonymous

a. Write a balanced chemical equation for this reaction.
b. What mass of KNO3 would be need to produce 18.4 liters of oxygen gas measured at 775 mmHg and 15 degrees Celsius.
c. What mass of KNO2 would also be produced?

2007-08-01 11:54:20 · 2 answers · asked by Anonymous

If reactants and products are brought to 298k and h20(l) is formed? And what is the maximum amount of useful work that can be accomplished under standard conditions by this system?

I have no idea how to solve this question. I'm assuming it will probably use some enthalpies of formation, so the enthalpies of formation are:
c2h4(g) 52.30
h20(l) -285.83
c02(g) -393.5
02 0
Thanks alot for the help

2007-08-01 11:33:55 · 3 answers · asked by Will 3

Is Calcium Iodate more soluble in pure water or in a solution containing KIO3?

2007-08-01 11:27:49 · 1 answers · asked by cbrice9 1

Given:
[HCl] = 0.100 M
Vol. of HCl need to reach Equivalence = 7.5 mL
Vol. of HCl needed to reach 1/2 Equivalence = 3.75 mL

Questions:

1. Determine the pKb and the Kb of the ammonium ion?

2. Calculate the concentration (M), of the aqueous ammonia solution?

2007-08-01 11:21:57 · 1 answers · asked by cbrice9 1

Given: [NaOH] = 0.100 M
pKa = 4.60
Ka = 2.50 x 10^ -5
Vol. of NaOH to reach Equivalence = 9.7 mL
Vol. of NaOH to reach 1/2 Equivalence = 4.85 mL

Question:

1. Calculate the concentration (M), of the diluted acetic acid solution?

2. Calculate the concentration of the original acetic acid solution?

Help!

2007-08-01 11:19:27 · 1 answers · asked by cbrice9 1

2007-08-01 10:50:28 · 1 answers · asked by louisito a. 1

i wish that i would be a millionare

2007-08-01 10:21:36 · 7 answers · asked by Anonymous

2007-08-01 08:34:12 · 2 answers · asked by k,b 1

Draw structural formulas for all the alcohols that have the molecular formula C5H11OH. Name each one and classify them as primary, secondary, or tertiary alcohols. Describe how they are formed and give two uses for this type of alcohol.



1-pentanol
2-pentanol (1-methyl-1-butanol)
3-pentanol
2-methyl-1-butanol
2-methyl-2-butanol
3-methyl-1-butanol
3-methyl-2-butanol
2,2-dimethyl-1-propanol

how do i classify if they are primary, secondary, or tertiary alcohols?

2007-08-01 08:33:46 · 4 answers · asked by Anonymous

I just need help with three problems.

1. A 0.75M solution has a pH of 2.0. Find Ka.

2. A 0.55M solution of a new acid, HX, has an equilibrium [H+]=4.1*10^-2. What is the value of Ka?

3. A base has a Kb=5.5*10^-12, if the concentration of a base is 0.36M, what is the equilibrium value of the hydroxide ion concentration?

I just really need to know what to do in these types of problems.

2007-08-01 08:18:04 · 1 answers · asked by Anonymous

2007-08-01 08:07:35 · 1 answers · asked by Anonymous

ok so i have the formula for a reaction of sodium carbonate and calcium chloride dihydrate to produce a precipitate of calcium carbonate.

Na2CO3(aq) + CaCl2. 2H2O(aq) -> CaCO3(s) + 2NaCl (aq) + 2H2O

So i have 1.0g of CaCl2. 2H2O. I put it in a beaker. How many grams of Na2CO3 for a full reaction to produce a precipitate of calcium carbonate?

Would it be 1.0g as well?

2007-08-01 06:20:33 · 3 answers · asked by Vienna 3

2007-08-01 05:58:27 · 7 answers · asked by wasif 1

name two metals you would not use and why?

2007-08-01 05:45:14 · 1 answers · asked by Anonymous

I'm using the vinegar to try to remove a mole and want stronger acid to make it work faster.

I tried evaporating the water by leaving the cap off the vinegar bottle, but after 3 days the vinegar is at the same level as when I started! So now I want to try boiling it. Will this work? Will it harm my plastic electric kettle that seems to have a teflon coated heating element? Thanks.

2007-08-01 05:11:16 · 5 answers · asked by Marvin 1

2007-08-01 05:03:13 · 2 answers · asked by Anonymous

I have a Chemistry project and one of the easier question I thought would be this, but I can't find it on the internet anywhere in an understandable form.

Thanks

2007-08-01 04:27:58 · 9 answers · asked by HarryREDUX 2

H2 +Cl2 gives 2HCl
here in the product, we have HCl as a compound, with valency 1 from hydrogen and chlorine and hence is balanced as 2HCl.
but why do we write H two and Cl two, i can see its got nothing to do with valency, so what is it? do different elements have a fixed number of those things? if so where can i find such a list for different elements?
Pleeze help!!

2007-08-01 04:18:54 · 3 answers · asked by merrick 2

what is the molarity of a solution prepared by dissolving 5.68 grams of NaOH in enough water to make 400. milliliters of solution?

How many grams of HCI is required to prepare 250 milliliters of a 0.158 M solution?

If 39 grams of benzene are dissolved in 100 grams of water, what is its boiling point? kb for water is 0.52 C/m

2007-08-01 03:06:52 · 2 answers · asked by Ashley T 1

I have a Chemistry project and one of the easier question I thought would be this, but I can't find it on the internet anywhere in an understandable form.

Thanks

2007-08-01 02:15:30 · 10 answers · asked by HarryREDUX 2

2007-08-01 01:14:07 · 3 answers · asked by Marie C 2

2007-08-01 00:33:16 · 4 answers · asked by trippkim 1

Help in Chemistry?
Plastics are generally produced from petroleum, but they can come from other sources as well! All that is really required is the ability to join molecules containing carbon and hydrogen together. Pls give me other sources for my chemistry project? that is available

2007-08-01 00:03:33 · 1 answers · asked by daikatana s 1