Chemistry - September 2007

2007-09-18 05:30:32 · 3 answers · asked by Anonymous

I've read it in a magazine but can't figure it out.

2007-09-18 05:13:14 · 5 answers · asked by dragon88 2

2007-09-18 04:20:20 · 4 answers · asked by John D 2

I have a quiz today, apparently...

If you can explain this so I can easily understand, thank you!! :D

2007-09-18 03:51:10 · 5 answers · asked by zenriek 1

the terms are:

1. isomers
2. isobars
3. isotopes
4. allotropes

2007-09-18 02:51:06 · 4 answers · asked by patel 2

In electrolytic cell, normally the metal in anode is oxidised to give out electrons and cathode takes electrons to from metal.
In zinc production, the anode is lead ( Pb) and the cathode is aluminium (Al) and the eletrolyte is zinc sulfate ( ZnSO4)
My question is why in the anode, the water is oxidised but not the lead metal???

2007-09-17 23:57:13 · 2 answers · asked by Anonymous

1.K
2. S
3.Kr
4. Ba

2007-09-17 23:19:28 · 4 answers · asked by avenger 2

Hi I am really stuck on these questions and any help would be appreciated:

1. calculate the number of atoms present in 1.50g of silver (Ag)

2. calculate the number of molecules present in 4.75 millimol of phosphine (PH3)

3. calculate the number of moles of the positive ions present in 9.71 grams of barium phosphide (Ba3P2)

2007-09-17 23:10:53 · 1 answers · asked by Sammie 2

A house with a 17.3 x 103 ft2 floor area and 8.00 ft high ceilings is to be heated with propane. How many kilograms of propane would be needed to raise the temperature of the air inside the house from 65.0 oF to
70.0 oF ?. In this calculation your are ignoring the temperature of the walls etc.

The moloar specific heat of the air inside the house is 30.2 J mol -1 oC -1
The average density of air over this temperature range can be estimated to be 1.22 g/L.
The molar mass of air is 29.1 g/mol.
There are 28.317 liters in a cubic foot.
The molar heat of combustion of propane is -2220.047 kJ/mol

2007-09-17 22:59:34 · 1 answers · asked by Bob L 2

Is it NaCl use in laboratory is the same with the table salt, so that we can infer that the table salt can be use to prepare NaCl solution also ??

2007-09-17 22:00:22 · 1 answers · asked by june y 1

Please give names of elements and theie allotropes.

Note: give other than that of carbon.

2007-09-17 21:58:56 · 4 answers · asked by Here's The Champ 2

I only have a vague understanding that the formation of pearls involves precipitation.

2007-09-17 21:39:37 · 3 answers · asked by j10f 2

2007-09-17 20:34:11 · 3 answers · asked by faye 1

2007-09-17 20:33:26 · 5 answers · asked by Mashy 1

2007-09-17 20:22:22 · 3 answers · asked by m4331n 1

2007-09-17 19:38:33 · 2 answers · asked by Mashy 1

A 50.0g piece of iron @ 152 C is dropped into 20.0g H2O(l) at 89 C in an open, thermally insulated container. How much water would you expect to vaporize, assuming no water splashes out? The specific heats of iron and water are 0.45 and 4.21 J/ g C , respectively, and Hvaporization = 40.7 KJ/mol H2O.

Help!!!


:(

2007-09-17 19:22:04 · 1 answers · asked by iQuestions 2

What is the mass of the beaker with the added mercury?

2007-09-17 18:46:03 · 1 answers · asked by Anonymous

Reiteration of question goes [here].

2007-09-17 18:43:32 · 14 answers · asked by C'thulhu 1

What purpose does the addition of finely divided charcoal serve during the recrystallization of impure solids?

2007-09-17 18:22:34 · 2 answers · asked by David N 1

a) will balloons filled with oxygen and other balloons filled with nitrogen rise or sink in air?

b) air is mainly a mixture of nitrogen and oxygen. Which gas is the main component? Explain how you have come to this conclusion.

2007-09-17 18:10:56 · 2 answers · asked by Anonymous

why 4-aminoacetophenone dissolves in 1M HCl, but is insoluble in 1M NaOH?

why benzoic acid dissolves in 1M NaOH, but is insoluble in 1M HCl?

4- aminoacetophenone is H2NC6H4COCH3
thank you!

2007-09-17 17:45:13 · 1 answers · asked by Chilipepper 1

Hey,

Our class was doing the unknown carbonate/bicarbonate lab. Here was the question:

It is possible to cause a carbonate to decompose if heated to a high enough temperature. Write an equation that describes what happens when sodium or potassium carbonate decomposes upon strong heating.

I thought it would be K2CO3 ===> K2O + CO2

2007-09-17 17:44:08 · 2 answers · asked by Eienstien's Ghost 1

2007-09-17 16:30:06 · 5 answers · asked by lia h 1

We're analyzing a sample of impure sodium carbonate, Na2CO3. I need to calculate the amount of it I need to react with about 25mL of approximately 0.1M HCl.
I know it's a simple question, but I've forgotten and can't figure it out.
I know i can obtain the Molar Mass of Na2CO3, but what would I do with that? And do I need the molarity1*volume1 = molarity 2 * volume 2 formula? or something like that. I don't know how to combine it all to figure it out.
Any help would be greatly appreciated!

2007-09-17 15:55:44 · 3 answers · asked by Sparkle 1

A. Solve the sequence formula Tn= 4n2 for n.
B. what term of the sequence is 196

-------------------------------------------------------------------------
tn=1000-3(n-1)

A. find n when tn= 850
B. which term of the sequence is 850?

2007-09-17 15:51:39 · 1 answers · asked by moviefan254 1

How many grams of CuSO4 * 5H20 are needed to prepare 100 mL of a .10 M solution?

2007-09-17 15:48:13 · 2 answers · asked by moviefan254 1

What gas if formed when lighting a match on top of the combination of alka-seltzer and water.

2007-09-17 15:40:44 · 1 answers · asked by iMarty 4

Can a regular person get some, and if so how much is it?

2007-09-17 15:38:15 · 2 answers · asked by Anonymous

Why are the outer-most electrons the only ones included in the orbital filling diagram and the electron dot diagram?

2007-09-17 15:31:04 · 3 answers · asked by IN0C3NT 2