Chemistry - April 2007

what is the balanced equation of:
__N2H4 + __H2O2 ---> __N2 + H2O

2007-04-21 15:49:41 · 2 answers · asked by r5091 2

Ok I have no idea how to approach this:

If 10.0g of washing soda crystals, of formula Na2CO3.10H20, are heated to remove all the water, what would the mass loss be?

I thought of maybe working out percentage by mass of H20, but how would you do that and if you did, what what you do then to get the answer??

Please, can you answer with explanations and details if you can.

Thanks a lot.

2007-04-21 15:41:15 · 3 answers · asked by Anonymous

1) Arsenic acid H3 As O4 is a tribasic acid. 25.0ml of a solution of the acid requires 35.7ml of a solution of sodium hydroxide of concentration 0.100 mol/L for neutralization. What is the concentration of the acid? and give the the equation for it.


2) A piece of iron wire weighs 0.2756g. It is dissolved in acid, reduced to the Fe2+ oxidation state, and titrated with 0.0200 mol/L potassium dichromate solution. What is the percentage purity of the iron wire? Use half-equations


3) 225g of iron wire was treated with sulphuric acid to convert it to Fe2+. All of the Fe2+ was placed in a 250ml flask and the solution made up to the mark with water. 25ml of this solution was titrated with a 0.00185 mol/L solution of potassium dichromate(VI). The volume required was 31.0ml. Calculate the percentage of iron in the wire. Use half equations.

2007-04-21 15:23:15 · 1 answers · asked by studentofscience 1

which of the following are strong acids and how do you know? which are the weak acids?

H2SO4, HI, HF, H3PO3, HNO3

2007-04-21 15:20:43 · 6 answers · asked by Anonymous

in the acid-base reaction CN^- + h2O > products, h2O acts as an ________ and one of the products is ________.

1: an acid or a base
2: OH^- or H3O^+

2007-04-21 15:19:12 · 1 answers · asked by Anonymous

the ionization constant K(subscript)w of water at 60 deg C is 1.0 x 10^-13. what is the pH of pure water at this temp?

2007-04-21 15:16:18 · 3 answers · asked by Anonymous

If you have any suggestions of websites that would have the physical properties of ionic and covalent compounds that would be great! Thanks! :)

2007-04-21 14:17:53 · 3 answers · asked by Anonymous

which banana would rot faster in a hot tem... and cold... tem give me both answer

2007-04-21 13:52:46 · 1 answers · asked by Anonymous

2007-04-21 13:10:41 · 4 answers · asked by Melissa H 1

Use in liquid gold and liquidgold in use for poliseon glass.

2007-04-21 12:57:17 · 1 answers · asked by br fzd 1

2007-04-21 12:44:52 · 1 answers · asked by COOL KID 2

2007-04-21 12:41:44 · 12 answers · asked by Didi 1

How many grams of the substance will dissolve in 250g of water

3.2 g
16 g
20 g
31 g

2007-04-21 12:40:28 · 6 answers · asked by Chelsea 1

1. Relative amounts in which moles of substance combine (2 words)... _ _ _er_t_o
2. Synonym for actual as in actual yield... _ e_ l
3. Amount of product obtainable under ideal conditions(2 words)... t_ _ _ _ _t_ _ _l _e_ l_

2007-04-21 12:02:25 · 5 answers · asked by Qu'est ce que tu penses? 6

2007-04-21 11:57:41 · 4 answers · asked by bayansh_sha 2

A teacher at my college had this on a test. I answered no and got it wrong. I researched it and found that sodium nitrate is used in bombs, explosives, and rocket propelents, but i found nothing about sodium nitrite being used in anything even similar.

2007-04-21 11:37:00 · 8 answers · asked by Addicted Chef 1

2007-04-21 11:17:59 · 5 answers · asked by Aurea R 1

using a bismuth molybdate catalyst

2007-04-21 10:51:15 · 1 answers · asked by kingsley m 1

2007-04-21 10:48:43 · 9 answers · asked by Meno 1

Ive been trying to figure out this problem for awhile now. Can anyone help? Thanks in advance.

How many electrons are transferred in the reaction of hydrogen peroxide with iron (II) ion in
acidic solution to form iron (III) ion and water?

2007-04-21 10:36:12 · 1 answers · asked by Johnny 1

Commercial electrolytic cells for producing aluminum operate at 5 volts and 100,000 Amperes. How long does it take to produce 1000 kilograms of aluminum? If electricity costs 9 cents per kilowatt hour, what is the cost of producing exactly 1 pound of aluminum?

2007-04-21 10:27:29 · 1 answers · asked by the Jam 2

2007-04-21 10:24:17 · 1 answers · asked by sindhu p 1

The K(a) of HF at 25.0 deg. C is 6.8 x 10^-4. What is the pH of a 0.35 M aqueous solution of HF?

show work please

2007-04-21 10:09:07 · 2 answers · asked by Zywiec 2

Commercial electrolytic cells for producing aluminum operate at 5 volts and 100,000 Amperes. How long does it take to produce 1000 kilograms of aluminum? If electricity costs 9 cents per kilowatt hour, what is the cost of producing exactly 1 pound of aluminum?

2007-04-21 09:23:35 · 1 answers · asked by Anonymous

2007-04-21 09:14:13 · 1 answers · asked by Daniel L 2

I'm trying to figure out some questions to study for a test .. can anyone help me out? ....Here they are :
1.) When do gases behave like real gases and when do they not?
2.) Why can we assume that the molecules of a gas occupy no volume and that there are no attractions or repulsions between molecules?
3.) The quantity of oxygen gas in a 34.0L balloon is increased from 2.7 grams to 5.3 grams at constant pressure. What is the new volume of the balloon?

2007-04-21 08:20:13 · 1 answers · asked by lilmace24 1

between the diffusion rate and the molecular weight? Is it R=1/(m^0.5) or is that just for gases? I have the diffusion rates and molecular weights of each dye. Or should I just use R1/R2=(m1^0.5)/(m2^0.5)? can I use that for liquid diffusion ? thank you

2007-04-21 07:54:27 · 1 answers · asked by Leo L 2

2007-04-21 07:20:45 · 4 answers · asked by Anonymous

Suppose you are studying coordination compounds of Co(II) with the ligand pyridine (py, C5H5N, MW = 79.10). You isolate a crystalline compound and since the only available ions are chloride and nitrate, you hypothesize the empirical formula of the coordinaton compound must be Co(II)w(py)x(Cl)y(NO3)z. You analyze for pyridine (Kb is approximately 10-9) by dissolving 0.1000 g of complex in 10 mL of water and titrating with a 0.01 M HCl solution. Which of the following indicators sould be used to detect the endpoint? (Assume that the initial concentration of pyridine is approximately 0.01 M.)
1/methyl red (pH range of color change: 4.8 - 6.0)
2/thymolblue (pH range of color change: 8.0 - 9.6)
3/bromophenol blue (pH range of color change: 3.0 -4.6)
4/alizarin yellow (pH range of color change: 10.1-12.0)
5/bromothymol blue (pH range of color change: 6.0 - 7.6)

2007-04-21 07:15:52 · 1 answers · asked by alissa f 1

Suppose you are studying coordination compounds of Co(II) with the ligand pyridine (py, C5H5N, MW = 79.10). You isolate a crystalline compound and since the only available ions are chloride and nitrate, you hypothesize the empirical formula of the coordinaton compound must be Co(II)w(py)x(Cl)y(NO3)z. Addition of AgNO3 to aqueous solutions of the complex results in a cloudy white precipitate, presumably AgCl. You dissolve 0.1000 g of the complex in water and perform a precipitation titration with 0.0500 M AgNO3 at the titrant. Using an electrode that is sensive to [Ag+], you reach the endpoint after 9.00 mL of titrant are added. How many grams of chloride ion were present in the 0.1000-g sample?

2007-04-21 07:12:36 · 3 answers · asked by alissa f 1