Chemistry - March 2007

For example i have the mass of each food sample burned and the heat energy gained in J and in calories

2007-03-14 14:59:33 · 2 answers · asked by Anonymous

how to solve: Please show with details on how its done

Formula: Ma*Va=Mb*Vb

Calculation: Ma=unknown Va=100mL Mb=1.0M Vb=45mL

2007-03-14 14:53:31 · 3 answers · asked by Anonymous

1) Calcium reacts w/water to form calcium hydroxide & hydrogen gas
2) Tetraphosphorus deoxide reacts w/water to from phosphoric acid
3) Mercury & Oxygen are prepared by heating mercury (II) oxide
4) Aluminum hydroxide and hydrogen sulfide from when aluminum sulfide reacts w/ water.

2007-03-14 14:45:43 · 2 answers · asked by truckin_90 2

An unknown volume of water at 18.2°C is added to 24.3 mL water at 35.6°C. If the final temperature is 23.5°C, what was the unknown volume? (Assume that no heat is lost to the surroundings; d of water is 1.00 g/mL.)

2007-03-14 14:37:09 · 7 answers · asked by pinay804 2

A biochemist prepares a lactate buffer by mixing 246.5 mL of 0.79 M lactic acid (Ka = 1.38×10-4) with 435.8 mL of 0.62 M sodium lactate. What is the pH of the buffer?

I cant seem to get this question. I set up my ICE Table and got an answer for the H+ of H30. Help please..

2007-03-14 14:32:29 · 3 answers · asked by Anonymous

2007-03-14 14:28:07 · 6 answers · asked by Anonymous

Hummm.. It's registration time at school for classes next year. I can't decide if I should take AP Chemistry. The teacher is pretty good, and I have had an A in Chemistry Honors all year.. Anyone who has taken it?

2007-03-14 14:25:28 · 5 answers · asked by Anonymous

2007-03-14 14:20:05 · 1 answers · asked by mbla06 1

Gasses Xpands to fill a vacuum. Why does earth's atmosphere gases not escape into the near-vacuum of space?

2007-03-14 14:17:14 · 6 answers · asked by truckin_90 2

What household product would you find sodium hydroxide?

and.. a drain cleaner has hydrochloric acid in it, right?

2007-03-14 14:14:28 · 3 answers · asked by Anonymous

Pls help...TY

2007-03-14 14:10:29 · 5 answers · asked by Anonymous

2007-03-14 14:09:45 · 2 answers · asked by Devil Woman 1

ok, so i need help with this chemistry problem(s)|||||

A gas sample at 83 degrees C occupies a volume of 1400 m3. At what temp. will it occupy 1200 m3?
> I got 4719 Kelvin|||||

A tank of compressed CO2 has a temp. of 23.6 C and a vol. of 31.4 L. The CO2 is completely transferred into a smaller tank that has a volume of 25.0 L. Assuming none of the CO2 escapes during the transfer, what is the temp. of the CO2 in the smaller tank if the temp. is lowered to achieve the same pressure as in the larger tank?
>>> I got 2.6 Kelvin||||||

Last problem,
A gas occupies .105 dm3 at 100 K. At what Celcius temp. will its vol. be at .140 dm3? assume the pressure remains constant.
>> With this question i guarantee that i got it wrong, my answer is -8.50 x 10 -5 K.||||||||||||||||||||||||


please and thank you ^_^

2007-03-14 14:07:44 · 2 answers · asked by Rumba 4

78) Name each compound:
A) SnBr2
B) BaSO4
C) Mg(OH)2
D) IF5

2007-03-14 14:06:48 · 3 answers · asked by truckin_90 2

2007-03-14 14:03:48 · 3 answers · asked by Anonymous

2 Mg(s) + O2(g) 2 MgO(s) ∆H = -1204 kJ

(a) How many grams of MgO are produced during an enthalpy change of 96.0 kJ?

(b) How many kilojoules of heat are absorbed when 7.80 g of MgO(s) are decomposed into Mg(s) and O2(g) at constant pressure?

2007-03-14 14:01:56 · 1 answers · asked by Ham Wallet 1

2007-03-14 13:40:54 · 5 answers · asked by Jon 1

Why is it that the electron configuration for calcium is 2, 8, 8, 2 and not 2, 8, 10? Is calcium special? For which other elements does the 3rd energy level only hold 8 electrons and not 18? What are the rules that govern the 3rd energy level?

2007-03-14 13:39:52 · 3 answers · asked by Anonymous

Pls give me a detailed answer. School project. Thanks!!

2007-03-14 13:33:20 · 1 answers · asked by kenny_och88 1

2007-03-14 13:26:37 · 3 answers · asked by sexxytee 1

true or false

2007-03-14 13:24:02 · 3 answers · asked by rtrt f 1

and also does anyone know where i can find a list that has every element and if its a metal nonmetal or metalliod?

2007-03-14 13:18:37 · 8 answers · asked by 123456789 2

true or false

2007-03-14 13:18:22 · 1 answers · asked by rtrt f 1

true or false

2007-03-14 13:16:46 · 1 answers · asked by rtrt f 1

true or false

2007-03-14 13:16:18 · 1 answers · asked by rtrt f 1

2007-03-14 13:11:14 · 2 answers · asked by Deyanira C 1

I'm in chem. right now, and we're learning about formula mass and mole mass. Can somebody show me how to get the formula mass for Ba(OH)2 and NaClO?

2007-03-14 13:07:24 · 0 answers · asked by Michelle S 1

Pb= 207.2 the mass of the amount of lead i have is 49.20 grams. what is the molar mass of this?

2007-03-14 13:03:56 · 2 answers · asked by Jon 1

I have found articles about these packets on the web, but cannot find out where to purchase them. Please help.

2007-03-14 13:03:39 · 1 answers · asked by Anonymous

Why do all bases possess common properties?
Hint: What do the names of some bases have in common?

i know the hint is that they all have OH-.
but i still don't get why.. =\

2007-03-14 13:03:07 · 3 answers · asked by Anonymous