Chemistry - April 2007

Please help thanks

2007-04-07 06:47:03 · 2 answers · asked by Laelaface 2

2007-04-07 06:46:39 · 1 answers · asked by bannah 1

An indicator has the reaction HIn(aq) <--> H+(aq) + In-(aq). Explain to me how the indicator can change color when a stong acid is poured into a solution of this indicator??

2007-04-07 06:45:50 · 4 answers · asked by Tracey Lee ♥ 2

2007-04-07 06:43:32 · 2 answers · asked by Crystal 1

2007-04-07 06:32:20 · 2 answers · asked by aka sweety 1

2007-04-07 06:31:30 · 3 answers · asked by Crystal 1

At room temperature, hydrogen peroxide will decompose slowly to form water and oxygen, as shown below

2H2O2-----> O2 + 2H2O

How many moles of hydrogen peroxide are used in the experiment to obtain 4800cm3 of oxygen?[one mole of any gas occupies 24.0 dm3 at room temperature?

Can u help me out with the workings too...

2007-04-07 05:05:13 · 2 answers · asked by blah,blah,blah 3

c) At 25oC and 2 atm CO2 is in the liquid state


d) At 20oC and 1 atm, solid CO2 will melt to liquid state

2007-04-06 19:43:12 · 4 answers · asked by crazytaco 2

whats the complete equatin for
NH3 + H2O =>

and also, what is the net ionic equation?




and also, if we add NH4Cl, which direction will the reaction shift? what if we add HCl?

2007-04-06 18:56:14 · 2 answers · asked by strawberry 1

Materials:water, two screw-top jars, teaspoon, teat pipette, 100ml beaker, 250ml beaker, distilled water, liquid soup, epsom salt
Procedure-
1.In the 100ml Beaker mix a teaspoon of liquid soup with 100ml of the distilled water to make soup solution.
2.In the 250ml beaker dissolve 1 teaspoon of Epsom salts in 200ml of distilled water to make hard 'island' water.
3.Pour distilled water into one srew-top jar and the same amount of island water into the other.
4.Use the pipette to put one drop of soap solution into the jar of island water.
5. Screw the lid on tight and shake.
6. If the water doesn't foam, add another drop of solution, screw on the lid, and shake it again.
7. Repeat till water foams.
8. Count how many drops of soap solution you need.
9. repeat the experiment using the screwtop jar of distilled water.
10. Record the number of drops needed to make the water and soap foam. How many drop did u need to make each jar foam and could you please describe each jar thx ^^

2007-04-06 18:08:23 · 3 answers · asked by Anonymous

read a book in which an atomic substance, with a short name, was disguised as salt and used for dastardly deeds. What is the name, I think it starts with a C.

2007-04-06 17:04:36 · 1 answers · asked by retep1964 2

anything about electron conversion in nucleus

2007-04-06 17:04:27 · 1 answers · asked by Anonymous

I understand that there is an ongoing debate in NASA that the ozone layer will eventually recover by itself at some point in time, but have there been any attempts at mass-producing ozone and trying to "fill the hole"? And yes, I'm aware that ozone is a poisonous gas. However, is it even possible for us to fix the hole chemically?

Coherant answers would REALLY be appreciated, thanks!

2007-04-06 17:00:47 · 12 answers · asked by takemeaway890 1

a)100.0ml of 0.010 M HCN and 200.0ml of .010 M NaC2H3O2

b)100.0ml of 0.010 HCl and 100.0ml of 0.020 M NH3

c)100.0ml of 0.020 M HOCl and 100.0ml of 0.010 M KOH

d)100.0ml of 0.010 M NaOH and 100.0ml of 0.010 M HC2H3O2

2007-04-06 16:35:43 · 1 answers · asked by V P 1

How similar are
-Biochemistry and Molecular Biology
-Chemistry

well in other words how much of overlapping is there? a lot?because for both majors it includes physics,biology,chemistry and mathematics.

2007-04-06 16:03:19 · 4 answers · asked by avalentin911 2

A 14.3 g sample of an unknown metal is heated to 94.0 oC and is placed in a coffee cup calorimeter containing 122 g of water at a temperature of 20.45 oC. After the metal cools, the final temperature of the metal and water is 23.35 oC. Calculate the specific heat capacity (in J/goC) of the metal, assuming that no heat escapes to the surroundings. (The specific heat capacity of water = 4.184 J/goC)

2007-04-06 15:45:56 · 2 answers · asked by lola c 2

What is the empirical formula according to this data?

Element: Weight in 10 g of sample

C 5.214
H 1.313
O 3.473

I got C2H5O. Is this correct?

2007-04-06 15:11:09 · 4 answers · asked by Alan l 1

A piece of unknown metal w/ a mass of 23.8 g is heated to 100.0 degrees celcius and dropped into 50.0 ml of water at 24.0 degrees celcius. The final temperature of the system is 32.5 degrees celcius. What is the specific heat of the metal? (Hint : the energy lost by one system is equal to the energy gained by the other system). Please show all your work.

2007-04-06 15:08:31 · 4 answers · asked by ? 1

if attractive forcer among solid particles are less than the attractive forces between the solid and a liquid, the solid will:

A) probably form a new precipitate as its crystal lattice is broken and re-formed

B) be unaffected because attractive forces within the crystal lattice are too strong for the dissolution to occur

C) begin the process of melting the form a liquid

D) dissolve as particles are pulled away from the crystal lattice by the liquid molecules

2007-04-06 14:49:02 · 1 answers · asked by salvamag145 2

The hybridization of the central atom in NO3- is

A. p3.
B. sp2.
C. sp.
D. sp2d.
E. sp.

2007-04-06 14:47:59 · 7 answers · asked by Anonymous

The density of an aqueous solution of HCl that is 20.00 percent by weight is 1.0980. Calculate the molarity (M) of this solution.

i need help for my test....please help me out....

2007-04-06 14:45:33 · 2 answers · asked by Anonymous

Calculate the molality of an aqueous solution that contains 31.600 % (w/w) in KCN. ?

Calculate the mole fraction of KCN in the solution described above (31.600 % (w/w) in KCN). ?

Calculate the mole fraction of water in the solution described in the previous two parts (31.600 % (w/w) in KCN). ?

i need these answers for my test review...please help me out....

2007-04-06 14:43:25 · 2 answers · asked by Anonymous

Given the reaction at equilibrium :
N2(g) + 3 H2(g) ↔ 2 NH3(g) + 92.05 kJ


a. State the effect on the number of moles of N2(g) if the temp of the system is increased
b. State the effect on the number of moles of H2(g) if the pressure on the system is increased.
c. State the effect on the number of moles of NH3(g) if a catalyst is introduced into the reaction system. Explain why this occurs

2007-04-06 14:31:23 · 1 answers · asked by A M 1

If you add 163.11 g if ice at 0.0 °C to 0.087 L of water at 39.9 °C and allow the water to cool to 0.0 °C, how many grams of ice will remain?

2007-04-06 14:19:16 · 2 answers · asked by Clue 1

This is for Chemistry, Gr.12 University course. We're on the Polymer section.

2007-04-06 13:31:25 · 1 answers · asked by Jeff Flynn 1

2007-04-06 12:45:12 · 2 answers · asked by zalyso 1

is this the best major for pre-med. Is this the best major to have a combination of biology and biology? Do you think that med schools will like a major in (BMB) and in Spanish.(I planned on doing this).?? Any comments?

2007-04-06 11:14:50 · 3 answers · asked by avalentin911 2

Can someone also draw out the initially-formed carbonium ion for attack at each position placing the + charge on the C atom at 2 to look at conjugation in the distribution of the remaining C-C double bonds? This is given as a hint for me to answer the above question. Thanks!!

2007-04-06 10:12:05 · 2 answers · asked by hqt5009 2

I know the formula mass Na = 22.9, O = 16, H = 1and density of 50% NaOH = 1.53


formula mass for NaOH = 40 approximately

and I write

X mol NaOH = 50 g NaOH (1 mol NaOH/ 40 gNaOH)
= 1.25 moles of NaOH
then:

100g NaOH soln. (1ml NaOH soln./1.53 NaOH soln.)
= 65. 36 ml = 0.0654 L
and:

M = # of moles of solute/ # of liters of solution
= 1.25 moles NaOH/0.0654 NaOH soln
= 0.019 M NaOH

This is not correct, can someone tell me where I have gone wrong?

2007-04-06 09:00:19 · 6 answers · asked by Anonymous

A.) C5H12 B.) CH2 C.) C3H9 D.) C2H2 E.) C3H6

2007-04-06 08:17:47 · 5 answers · asked by jose t 1