Chemistry - March 2007

1 CHsub4 (g) + 2 Osub2 -----> 2 H(sub2)0 + 1 CO(sub 2) + 212.8 kcal
How many moles of methane are needed to make
5.98 X 10^5 kcal of heat?
If 445.2 kcal of heat are released in this reaction, how many moles of oxygen were used? grams of oxygen?
Thank you!


Thank you

2007-03-25 15:08:43 · 4 answers · asked by Hannah C 1

a. Explain why liquids in a test tube form a meniscus
b. compare vaporization and evaporation

2007-03-25 15:01:55 · 1 answers · asked by SiR SmoKe a LoT 1

1. a What restrictions are there on the use of Gay-Lussac's law of combining volumes?
b. At the same temperature and pressure, what is the relationship between the volume of a gas and the number of molecules present?

2007-03-25 14:52:29 · 3 answers · asked by Whisper G 1

2007-03-25 14:51:33 · 2 answers · asked by Anonymous

(For each, write the equation for the dominant equilibrium which determined the pH, and justify your pH prediction)

(a) 100 mL of 0.10 M C5H5N; Kb = 1.5x10^-9

(b) 100 mL of 0.10M Ca(NO3)2

(c) 100mL of 0.10 M NaH2PO4; Ka1 = 7.1 x 10^-3; Ka2 = 6.3 x 10^-8; Ka3 = 4.2 x 10^-13

(d) 100 mL of 0.10 M K2PO4; Ka = See above.

(e) 100mL of 0.100 M Na3PO4; Ka = see above.

2007-03-25 14:47:33 · 1 answers · asked by Anonymous

19. Convert each of the following Kelvin temperatures to Celsius temperatures:

a. 273 K
b. 350. K
c. 100. K
d. 20. K

2007-03-25 14:39:03 · 3 answers · asked by Whisper G 1

Convert each of the following Celsius temperatures to Kelvin temperatures:
a. 0. C
b. 27 C
c. -50 C
d. -273 C

2007-03-25 14:36:47 · 2 answers · asked by Whisper G 1

Starting with 13.2 ml of 3.80 × 10−2 M AgNO3, how many grams of KBr can be added to the solution before AgBr begins to precipitate ?

2007-03-25 14:34:12 · 2 answers · asked by woj87marta 1

trying to find process/equation to calculate atoms to molecules to atoms

2007-03-25 14:32:45 · 1 answers · asked by theoneandonly 1

Which of the following has nonpolar bonds?
-H2S
-HCl
-OF2
-Br2
-All are nonpolar

Please explain

2007-03-25 14:27:04 · 1 answers · asked by Anonymous

4. How do gases compare with liquids and solids in terms of the distance between their molecules?

2007-03-25 14:26:26 · 7 answers · asked by Whisper G 1

k=slope=0.46 (I don't know if we need the slope to do this by the way) please help, I have no idea how to do this.

2007-03-25 14:09:51 · 1 answers · asked by Curious Sarah 2

1. Why is it that when we put a straw in a cup full of water, and then put our finger over the top of the straw, the water gets caught in the straw?
2. Why is it that when we put one straw inside a cup of water and another outside of the cup, and we put both of the straw's ends in our mouth and suck, it is hard to drink the water?

(If you can please explain it in scientific terms, if not then that is okay)

2007-03-25 14:08:44 · 1 answers · asked by Anonymous

Cu(2)S + HNO(3) ---> Cu(NO(3))2 + CuSO(4) + NO(2) + H(2)0

and name it if you can in their real chemical names. I have been trying forever, and I cant figure it out! PLZ HELP! The numbers in the perenthesis are subscripts. So please try and balance it!...Thx

2007-03-25 14:04:24 · 2 answers · asked by justachick 2

2007-03-25 14:01:13 · 2 answers · asked by Connie L 1

The pH of 100 mL of a 0.10M aqueous solution of Compund Z is 11.30.

1. Is Z an acid, a base, neither, or cannot be determined?

2. Write the relevant Brownsted-Lowry equation showing how Z behaves in aqueous solution, and calculate the value for the equilibrium constant for the reaction shown by the equation.


??? I really don't get how I'm supposed to approach this...

Thanks

2007-03-25 13:53:10 · 2 answers · asked by Anonymous

If I am given a list of the following pairs of solutions how can I decide which ones will be a buffer solution? i have:
1)20 ml 0.10M NaI and 40ml 0.10 M HI
2) 20ml 0.10 M NH4Cl and 40ml 0.10 M NH3
3)20ml 0.10 M HCl and 40ml 0.10 M NH3
4) 20ml 0.10 M CH3COOH and 20ml 0.10M CH3COONa
I know the answer is 2,3 and 4 but how is this determined?

2007-03-25 13:43:27 · 2 answers · asked by Anonymous

1. A gas has a volume of 300.0 mL at a pressure of 740 mm Hg. Calculate its volume if its pressure quadruples at a constant temperature and mols.

2. A sample of Helium has a volume of 35.0 mL at 1.25 atm. If the helium is compressed to a volume of 10.0 mL at constant temperature, what is the new pressure of the helium gas?

2007-03-25 13:38:55 · 3 answers · asked by Anonymous

a) 0.96 g MgCl2 in 500 mL of solution
b) 9.33 g Na2S in 450 mL solution
c) 2.48 g CaF2 in 375 mL of solution

2007-03-25 13:24:14 · 2 answers · asked by Mich 1

If you have a .20M solution of potassium iodide, and use 20.0 ml, how do you find the mols of Iodide ions? Please show work, thank you.

2007-03-25 13:22:36 · 2 answers · asked by Anonymous

How are water and ethyl alcohol alike in their polarities??

2007-03-25 13:17:30 · 2 answers · asked by NoNameNoFace 2

Would you use only one ball to represent the nucleus and the proton, or two balls to represent them?

2007-03-25 13:17:05 · 4 answers · asked by Anonymous

2007-03-25 13:10:50 · 1 answers · asked by Anonymous

2007-03-25 13:10:33 · 2 answers · asked by Anonymous

Its involves by heating the samples, evaporating, weighing and comparing weights and calculating, but I want to know how exaclty to cary this experiment should be done.

2007-03-25 13:10:25 · 1 answers · asked by Anonymous

2007-03-25 12:55:51 · 4 answers · asked by Anonymous

1. A gas occupies 12.3 liters at a pressure of 40.0 mm Hg. What is the volume when the pressure is increased to 60.0mm Hg?

2. If a gas at 25.0 degrees Celsius occupies 3.60 liters at a pressure of 1.00 atm, what will be its volume at a pressure of 2.50 atm?

3. Calcute the change in temperature when 2.00 L at 20.0 degrees celsius is compressed to 1.00 L?

2007-03-25 12:55:06 · 1 answers · asked by Anonymous

KClO3 heated in the presence of the catalyst MnO2 yields KCl and O2

2007-03-25 12:52:17 · 1 answers · asked by Anonymous

I've read that it could be sponatneously flammable with oxygen when heated, but is it flammable?

2007-03-25 12:51:42 · 3 answers · asked by Anonymous

I know this is a strange question but for some reason I feel connected to Chemistry because of what complication it has. I am new to this (completely) but I have a strange attraction to learn it. I like how Chemistry works such as formulas and Chemicals rather than making colors or fumes. I know basic chemistry but i am only in the 9th grade. I go to a community college for a program and I want to hear your responses on this. Should I try it or something I should steer clear from? How did you find out Chemistry and why did you choose to stick with it? Please leave me comments because his is something that is new and i want to find out more about it. I will bring additional information if you need it. Thanks for reading!

2007-03-25 12:48:08 · 3 answers · asked by magickookami 1