Chemistry - March 2007

help me, how to write a chemical equation.Give me some example.

2007-03-25 01:12:12 · 8 answers · asked by nazati 2

what and why is radioactivity dangerous?

2007-03-25 00:37:58 · 4 answers · asked by DaneMaricich 3

There is a chemical rection take place, but i don't know what the reaction is...The reaction reverses when the hand warmer is heaten up, but i don't know why the chemical compound can go back to the coin again.

2007-03-25 00:07:32 · 7 answers · asked by David M 1

2007-03-25 00:02:00 · 8 answers · asked by Anonymous

detailed information and links would be much apreciated

2007-03-24 23:55:46 · 3 answers · asked by danny s 1

2007-03-24 23:36:25 · 6 answers · asked by Welshdragon 5

What is a hydrocarbon in Chemistry terms?
Can i have some examples of a hydrocarbon?

2007-03-24 23:13:05 · 11 answers · asked by The Stressed.. 2

Starting with 11.8 ml of 3.40 × 10−2 M AgNO3, how many grams of KBr can be added to the solution before AgBr begins to precipitate ?

2007-03-24 23:05:55 · 1 answers · asked by Anonymous

please try to answer me. why does the vapors of tea smell tea and the vapors of coffee smell coffee? what is responsible for the aroma in any food item?

2007-03-24 22:50:54 · 4 answers · asked by Rechu 2

just tell me why and does any of functional group have some affect on it

2007-03-24 22:45:10 · 1 answers · asked by chemist 1

2007-03-24 22:36:02 · 10 answers · asked by buddhu ram 1

Or how their characteristics may change?

2007-03-24 22:33:26 · 1 answers · asked by saran 1

2007-03-24 22:31:29 · 16 answers · asked by srinath_chessplayer 1

These questions are from my homeschooling. I'm very confused about these questions, so it would be very helpful if you could explain each one a little.


A) The maximum number of electrons that can be held in the valence shell of beryllium is 8. Would beryllium be more likely to lose or gain electrons in a chemical reaction?

B) If beryllium formed an ion, what would be it's chemical formula?

C) With which of the following elements would beryllium most likely form an ionic bond?

Na
Ca
Fe
Br

I think question C would be Ca.

I would just ask my teacher to explain this stuff to me, but I don't have one.

2007-03-24 20:55:20 · 7 answers · asked by dex4774 1

Starting with 14.0 ml of 3.50 × 10^−2 M AgNO3, how many grams of KBr can be added to the solution before AgBr begins to precipitate ?

2007-03-24 20:52:20 · 2 answers · asked by meister 2

1. The Solvay process for the manufacture of sodium carbonate involves the following reactions:
NH3(g) + H2O(l) + CO2(g) -(arrow sign) NH4HCO3(aq)
NH4HCO3(aq) + NaCl(aq) -(arrow sign) NH4Cl(aq) + NaHCO3(s)
2NaHCO3(s) -(arrow sign) Na2CO3(s) + H2O(g) + CO2(g)

Calculate the masses of ammonia and sodium chloride required to produce 150.0kg of pure anhydrous sodium carbonate.

Note:I have been stuck on this one question for 2 hrs, 15 minutes and I just can't work it out correctly. I have a large chemistry text books and another booklet. I don't know the processes involved in finding the answers. Could you please show me the correct working and answers and then at the bottom explaining it all to me. I'm NOT trying to get you to do my homework. I just need serious help! Please help chem whizzes! Thankyou so much. Best answer gets 10 points!

2007-03-24 20:39:27 · 6 answers · asked by Anonymous

2007-03-24 20:16:07 · 5 answers · asked by arslantariq 2

My book says that BO=number of shared pairs linking X and Y/ (number of X-number of Y links in the molecule or ion)... I'm a bit confused... other books mention antibonding and bonding.. can someone please help me understand....

2007-03-24 20:14:19 · 2 answers · asked by bluebrigadeband 1

Is it two?

2007-03-24 20:12:59 · 8 answers · asked by dex4774 1

what's with phosphate? oxygen inside the bubbles?

2007-03-24 19:57:21 · 4 answers · asked by eartha_yu18 1

How many mL of 2.0 molar HCl are required to dissolve 0.350 g of FeS?

(FeS + 2HCl ---> FeCl2 +H2S)

2007-03-24 19:54:05 · 6 answers · asked by hiscageofstars 1

To test for chalk, a soil sample (4.5g) was dissolved in 9.0mL of HCl (1.00mol/L). The unused acid was titrated against 1.0 molar NaOH(aq); titre value 3.50mL. Calculate the chalk (CaCO3) content as % by mass in the soil sample.

2007-03-24 19:51:01 · 2 answers · asked by hiscageofstars 1

A 4.372 g sample of hydrated strontium nitrate forms 3.26 g of anhydrous strontium nitrate Sr(NO3)2, when its water of hydration is removed. Find its degree of hydration.

2007-03-24 18:24:16 · 2 answers · asked by Anonymous

2007-03-24 18:06:45 · 1 answers · asked by lennie 1

calculate the C=O bond energy given the following equations.

C (g ) + O2 (s) --> CO2 (g ) (-393 KJ/mol)

C (s ) --> C (g ) --> (+715 KJ/mol)

1/2O2 (g ) --> O (g ) ( +248 KJ/mol)


Please please please explain in the duh-est way possible. Imagine you're talking to an idiot

Thanks :P

2007-03-24 17:58:52 · 2 answers · asked by Chocolate Strawberries. 4

The spectres- how do you make them fire IRBS more rapidly?

2007-03-24 17:57:49 · 1 answers · asked by Mike Jones 2

2007-03-24 17:26:32 · 2 answers · asked by Tina the llama 2

2007-03-24 17:18:20 · 4 answers · asked by Anonymous

the half life of Strontium-90, (^90)Sr is 25 years. that is, half of any given quantity of ^90Sr will disintegrate after 25 years. if the initial mass of a quantity of ^90Sr is 2 gm, write down a formula for the mass m(t) that remains after t years. hence find the mass that remains after 200 years and also find the number of years it takes for this quantity of ^90Sr to have a mas of 1/64 gm.

2007-03-24 17:09:42 · 4 answers · asked by jimmy 1

1. The Solvay process for the manufacture of sodium carbonate involves the following reactions:
NH3(g) + H2O(l) + CO2(g) -(arrow sign) NH4HCO3(aq)
NH4HCO3(aq) + NaCl(aq) -(arrow sign) NH4Cl(aq) + NaHCO3(s)
2NaHCO3(s) -(arrow sign) Na2CO3(s) + H2O(g) + CO2(g)

Calculate the masses of ammonia and sodium chloride required to produce 150.0kg of pure anhydrous sodium carbonate.

2. A 2.750g sample of zinc carbonate was treated with a solution containing 0.0500 moles of hydrochloric acid.
ZnCO3(s) + 2HCl(aq) -(arrow sign) ZnCl2(aq) + H2O(l) + CO2(g)

Find the
a) limiting reactant
b) mass of carbon dioxide
c) mass of zinc chloride that could be recovered
d) mass of remaining reactant

NOTE: How do I show the working on my page for each of the questions for my teacher? I have the answers (I am not 100% sure of them though) but my setting out doesn't look right. Could you please show the correct working out if possible before the answer. Thankyou.

2007-03-24 16:52:15 · 1 answers · asked by Anonymous