Chemistry - September 2006

2006-09-19 05:38:04 · 11 answers · asked by simonwien_61_uk 1

Just checking. I could have listed this under physics as well.

2006-09-19 05:17:52 · 8 answers · asked by But why is the rum always gone? 6

How to extract magnesium from magnesium sulfate? (magnesium salt) Now if your not telling me how it can be extracted in this way or an easier way to extract it at home from something else...then plz dont bother answering thank you.

2006-09-19 05:16:12 · 3 answers · asked by Illya W 1

Diethylcathinone and Methcathinone?

2006-09-19 05:05:24 · 7 answers · asked by Vincent Valentine 5

need step by step instructions

2006-09-19 04:44:45 · 5 answers · asked by rudedogg 1

DH for a reversible process that takes place within a certain system is -55.00 kJ.
What is DS (J/K) of the surroundings ? The temperature is constant at 55.0oC for both the system and the surroundings.

2006-09-19 04:31:36 · 2 answers · asked by crazycuty4eva 1

Given the following data:


2Mg + O2 → 2MgO DH = −1204


MgO + H2O → Mg(OH)2 DH = −37


2H2O → 2H2 + O2 DH = +572 kJ




Calculate DH for the reaction


Mg + H2 + O2 → Mg(OH)2

2006-09-19 04:30:32 · 1 answers · asked by crazycuty4eva 1

2006-09-19 04:24:15 · 1 answers · asked by sochn9022jkl 1

2006-09-19 04:18:50 · 6 answers · asked by rainbowshade4 1

Refering to Cations being found in river water, Also who else uses it and why,how e.t.c. needed by Tuesday

2006-09-19 04:16:21 · 6 answers · asked by Anonymous

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2006-09-19 04:11:45 · 6 answers · asked by rainbowshade4 1

2006-09-19 03:32:56 · 17 answers · asked by Anonymous

2006-09-19 03:31:53 · 4 answers · asked by mahsa b 2

Water has 3 states. So at 4 degree Celsius, what happens?

2006-09-19 03:26:37 · 7 answers · asked by stormalive_32722 2

Calculate the percentage yield of aspirin from this experiment if you obtained 2.6 g of aspirin when starting with 2.5 g of salicylic acid. The percentage yield is the amount of product you obtained as a percentage of the amount of product that would be produced if the reaction produced 100%, based on stoichiometry.Percentage yield of aspirin (to at least 1 decimal place)

2006-09-19 03:26:08 · 1 answers · asked by Anonymous

1: Which element is the most abundant on earth?
Water, (H2O)

Hydrogen, (H2)

Oxygen, (O2)

None of the above


2: Oxygen is a diatomic element which means that 2 atoms of oxygen combine to form an oxygen molecule, (O2). The number 2 in (O2) means that this oxygen molecule has _______________.
two atoms of oxygen

two atoms of water

two atoms of hydrogen

none of the above


3: Water, (H2O), contains Oxygen and Hydrogen. The oxygen in water, (H2O) does not have a subscript, which means 1 is understood and there is only 1 oxygen atom in a molecule of water (H2O). Please answer the following: How many Hydrogen atoms are there in a molecule of water, (H2O)?
1

2

3

4


4: Since we are talking about (H2O), it will be important for you to know that hydrogen (H2), like Oxygen (O2), is also diatomic. Which of the following molecules are diatomic?
Fluoride, (F2)

Chlorine, (Cl2)

Nitrogen, (N2)

all of the above


5: A molecule of water, (H2O), is the smallest amount of water that can exist and still retain all the properties of water. H2O represents 1 molecule of water because a number 1 is assumed to be in front of the H. Which of the following represents 1 molecule?
Nitrogen, N2

Chlorine, 2Cl2

Fluoride, 3F2

none of the above


6: 3F2 consists of 3 molecules of F2 (Fluoride) because there is a 3 in front of the F2. Given: S2, how many molecules of Sulfur are there?
1

2

3

4


7: Given: KI, potassium iodide. How many molecules of potassium iodide are there?
1

2

3

4


8: In the preceding problem you were given the chemical formula for potassium iodide, KI. Please notice that in the compound KI, there is no space typed between the K and the I. Based on your understanding of this new language you are learning, please choose the compound from those listed below that represents 2 molecules of sodium chloride, which is table salt, symbolized as NaCl:
NaCl

2NaCl

3NaCl

none of the above


9: How many molecules are there in 3NaBr?
1

2

3

none of the above


10: The chemical formula for Ozone is O3. Please determine the number of molecules in the following amount of ozone, 5O3.
1

2

4

5


11: Matter can exist in three states: Solid, Liquid or a Gas. Is the oxygen, O2 that we come into contact every day, a solid, liquid or a gas?
O2 is a solid

O2 is a liquid

O2 is a gas

none of the above


12: Water, H2O, commonly exists as a solid, a liquid, or a gas. The air we breathe contains N2, O2, water vapor and a few trace elements. When there is a lot of water vapor in the air, we say that the weather is humid. How many water molecules are in 10 H2O?
5

10

15

20

2006-09-19 03:08:53 · 7 answers · asked by Anonymous

ok, i have 2 questions, which out of 10 i cannot answer.
1] decribe the bonding arrangement in the benzene ring.
2]what role do delocalised electrons play in the bonding arrangement?
i really need help on these two questions, if you can help, much appreciated. thanks

2006-09-19 02:44:05 · 4 answers · asked by Anonymous

2006-09-19 01:58:55 · 5 answers · asked by AHMED A 1

I have just done an experiment, and found out that lime juice is more acidic than oranges and oranges are more acidic than watermelons.. What is the cause of this? Please don't just say because lime juice is more sour. Scientific answer plz!

2006-09-19 01:52:16 · 6 answers · asked by Mcdz 1

amalgam is an alloy of mercury and pls be sure before answering!!!!!!!1

2006-09-19 01:03:16 · 7 answers · asked by ria 2

Procedures on how to extract tannin from tea leaves? Specific and cite references please! Really appreciate it! Please take this seriously!

2006-09-19 00:45:12 · 4 answers · asked by Cho 4

2006-09-19 00:22:32 · 11 answers · asked by gaurav S 1

2006-09-18 23:54:23 · 3 answers · asked by ayubp 2

2006-09-18 23:39:39 · 13 answers · asked by aira_love21@yahoo.com 1

2006-09-18 23:10:29 · 13 answers · asked by Anonymous

I am not chemistry teacher, but Maths and Physics in a small school. Can you help me with amusing experiments, their formulas and what are they teaching the kids? (10 to 15 years old)
i.e. Make smoke, make sparkles, small bangers, colour changes etc... to keep them interested.

2006-09-18 21:59:16 · 4 answers · asked by just "JR" 7

Where, when and for what reasons has it been developed

2006-09-18 20:19:48 · 7 answers · asked by Anonymous

INDIAN / INTERNATIONAL PRICES CAN QUOTE.

2006-09-18 18:50:40 · 1 answers · asked by kzpc 2

2006-09-18 18:21:09 · 7 answers · asked by jerioth w 1

2006-09-18 18:19:51 · 5 answers · asked by rajeevpjoshi 1