Chemistry - April 2007

2007-04-01 17:45:11 · 2 answers · asked by Qian Z 1

2007-04-01 17:44:19 · 2 answers · asked by Qian Z 1

Ahh, I'm havig the hardest time on my homework. Please help me. I just dont want the answers please tell me how you did it!

1. AMmonia has the chemical formula NH^3. Suppoose you have 3.0 moles of ammonia.

a) how many molecules of NH^3 are in 3.0 moles of ammonia
b) how many atoms of H are in 3.0 moles of ammonia
c) what is the mass of 3.0 moles of ammonia in grams

2007-04-01 17:37:24 · 2 answers · asked by num1grl 2

I would appreciate a example with an ICE Table. I don't know the Ka. My question also is Ka gotten from a table or can you find it through the data given?

2007-04-01 17:36:58 · 1 answers · asked by kevin5782 2

conjecture a model for the number of carbon 14 atoms that haven't decayed from an initial number?

A half-life is the time it takes for half the parent radioactive element to decay to a daughter product. Radioactive carbon-14 is present in the atmosphere and all living things, which absorb it. Upon death a plant or animal no longer absorbs carbon 14 and its amount starts to decrease through radioactive decay so that after 5730 years there is only half the amount of carbon 14 that would be expected in a living plant or animal.

1. Use the info to conjecture a model for the number of carbon-14 atoms that have not decayed from an initial number.

2. In a sample of bone discovered in a Neolithic grave, the amount of radioactive carbon-14 was found to be only 1% of that in living things. How old was the bone?

could someone please help me with this, i really have no idea how to do it

2007-04-01 17:36:08 · 1 answers · asked by Anonymous

In a coffee-cup calorimeter, 66.3 mL of 0.100 M AgNO3 and 66.3 mL of 0.100 M HCl are mixed to yield the following reaction.

Ag+(aq) + Cl -(aq) ----> AgCl(s)

The two solutions were initially at 22.60°C, and the final temperature is 23.39°C. Calculate the heat that accompanies this reaction in kJ/mol of AgCl formed. Assume that the combined solution has a mass of 132.6 g and has a specific heat capacity of 4.18 J/°Cg.

2007-04-01 17:35:17 · 1 answers · asked by help 1

2007-04-01 17:33:41 · 2 answers · asked by yue c 1

A half-life is the time it takes for half the parent radioactive element to decay to a daughter product. Radioactive carbon-14 is present in the atmosphere and all living things, which absorb it. Upon death a plant or animal no longer absorbs carbon 14 and its amount starts to decrease through radioactive decay so that after 5730 years there is only half the amount of carbon 14 that would be expected in a living plant or animal.

1. Use the info to conjecture a model for the number of carbon-14 atoms that have not decayed from an initial number.

could someone please help me with this, i really have no idea how to do it

2007-04-01 17:30:05 · 3 answers · asked by Anonymous

2007-04-01 17:27:40 · 3 answers · asked by ÀÖÑô Õ 1

Li + H2O
Na +H2O
K + H2O

2007-04-01 17:23:05 · 3 answers · asked by Lana 1

1. C12H22O11 ----> 12CO2 + 11H2O
2. 2C12H22O11 + O2 ----> 24CO + 22H2
3. C12H22O11 + 6O2 ----> 6CO2 + 11H2O
4. C12H22O11 ----> 12C + 11H2 O


Thanks

2007-04-01 17:01:06 · 1 answers · asked by Anonymous

2007-04-01 16:58:04 · 2 answers · asked by jack g 1

2007-04-01 16:56:02 · 1 answers · asked by jack g 1

Calculate the melting point of benzoic acid (C6H5CO2H), given the following data, Hfusion = 17.3 kJ/mol and Sfusion = 43.8 J/(Kmol) in Celcius.

2007-04-01 16:51:27 · 1 answers · asked by chester_k_guidry 2

Thanks.

2007-04-01 16:51:14 · 1 answers · asked by Anonymous

2007-04-01 16:38:58 · 5 answers · asked by Samantha S. C. 1

Iron (III) nitrate and iron (III) acetate have a large solubility product constants. Yet the farmer does not find these compounds useful to add to iron deficient soils. Explain.

2007-04-01 16:30:14 · 1 answers · asked by kiwi 1

1. 2C12H22O11 + O2 ----> 24CO + 22H2
2. C12H22O11 ----> 12CO2 + 11H2O
3. C12H22O11 + 6O2 ----> 6CO2 + 11H2O
4. C12H22O11 ----> 12C + 11H2 O

2007-04-01 16:26:22 · 1 answers · asked by Anonymous

The weak base methylamine ( CH3NH2 ) has Kb = 5.0 x 10^-4 . Calculate the pH and pOH in a 0.25M solution of methylamine

2007-04-01 16:12:51 · 1 answers · asked by Timeless 2

2007-04-01 16:02:07 · 3 answers · asked by Anonymous

2007-04-01 15:59:45 · 1 answers · asked by besho 1

2007-04-01 15:34:36 · 1 answers · asked by mei s 1

Like i know it has something to do with their chemicals and what they reflect
can you give me a short description please?
tanks you

2007-04-01 14:59:18 · 8 answers · asked by Thrills 5

A helium filled balloon contains 124mL of gas at a pressure of 0.979 atm. What volume will the gas occupy at standard pressure? answer in units of mL

2007-04-01 14:45:45 · 1 answers · asked by nikki 1

2007-04-01 14:32:10 · 5 answers · asked by iwonder 4

You have a sample of C4H9Cl. You are not sure what the exact structure of the molecule is. You do two trials of a reaction with this molecule:

Trial 1: .10M C4H9Cl and .10M Br-
Trial 2: .10M C4H9Cl and .20M Br-

you notice that in the second trial, the reaction occurs twice as fast. What mechanism is probably followed (Sn1, Sn2, E1, E2)? Choose a possible starting molecule. Draw mechanism if at all possible.

2007-04-01 14:29:15 · 2 answers · asked by JaJarvis 1

a) 60.0 mL of methanol in a total volume of 500.0 mL

b) 25.0 mL of rubbing alcohol (C3H7OH) diluted to a volume of 200.0 mL with water.

2007-04-01 14:24:08 · 3 answers · asked by Anonymous

If the temperature of two substances (of equal mass) is raised by 20 degrees Celsius, which substance would absorb the most energy: the substance with the lower molar heat capacity or the substance with the higher molar heat capacity?

2007-04-01 14:11:52 · 2 answers · asked by Nowhere Man 6

How do I draw the Lewis Structure for these Molecules?
1) (NH4)2SO3

2) LiBH4

2007-04-01 14:09:08 · 2 answers · asked by ovipero@sbcglobal.net 2

write the equation for the reaction that takes place when a solution of silver nitrate is added to a solution of sodium chloride???

sodium bicarbonate and sodium chloride are both soluble in water. will a double replacement reaction take place if a solution of sodium bicarbonate is added to a solution of sodium chloride? explain.

2007-04-01 13:57:09 · 1 answers · asked by lilprincess_2good4u 1