Chemistry - November 2007

2007-11-11 15:36:07 · 1 answers · asked by Elninotorres 1

2007-11-11 15:28:07 · 7 answers · asked by jesicaxnn 1

How did J.J. Thomson come to the conclusion through his cathode ray experiment that electrons, or "corpuscles," have about 1000 times less mass than a hydrogen atom? I know this assumption was incorrect, but how did he arrive at this calculation in the first place?

2007-11-11 14:54:44 · 1 answers · asked by Jewel1016 2

a) The activation energy of a certain reaction is 37.2 kJ/mol. At 20 degrees C, the rate constant is 0.0130 s^-1. At what temperature would this reaction go twice as fast? (I got part a - answer: T_2 =33.9 degrees C. Just need help on part b)

b) What would the rate constant be at a temperature of 100 degrees C?

2007-11-11 14:15:03 · 1 answers · asked by Mike S 1

2007-11-11 13:56:59 · 1 answers · asked by ? 4

Well i jsut did an experiment where i heated copper sulfate then i weighted the contents.

Here are my observations:

mass of crucible + lid= 20.144g
mass of crucible + lid+ copper sulfate = 23.827g
mass of copper sulfate 3.689
mass of crucible + lid+ contents= 22.577g

I need to find the mass of the hydrate used.

Calculate the mass of water of hydration lost.

and calclate the mass of dehydrated salt remaining (CuSO4)


Can anyone help me on these 3 problems. Can anyone help me out?

2007-11-11 13:44:02 · 1 answers · asked by Anonymous

2007-11-11 13:43:12 · 1 answers · asked by jwhitesj 2

Starting with 14.6 ml of 4.20 x 10-2 M AgNO3, how many grams of KBr can be added to the solution before AgBr begins to precipitate ?

2007-11-11 13:41:13 · 1 answers · asked by SomeOne 1

a) measured at constant temperature and pressure
b) that equal 1 L
c) that equal 22.4 L
d) measured at STP

2007-11-11 13:28:16 · 1 answers · asked by Anonymous

What happens to volume of a gas sample if the number of moles of a gas is doubled under constant temperature and pressure?

2007-11-11 13:27:20 · 3 answers · asked by decemberkitty02 3

thank you for helping ; )

2007-11-11 12:55:55 · 2 answers · asked by Anonymous

do moth balls conduct? do they have high boiling points? are the solbule in water?

2007-11-11 12:39:32 · 2 answers · asked by Anonymous

what is the percentage yeild of the reaction if 2 grams of H2 produces 18 grams of H2O?

2007-11-11 12:34:43 · 2 answers · asked by Anonymous

2007-11-11 12:32:20 · 1 answers · asked by Anonymous

A) mixture of 82.49 g Aluminum (26.98 g/mol) and 117.65 g Oxygen (32 g/mol) is allowed to react. What MASS of aluminum oxide (101.96 g/mol) can theoretically be formed.

4AL + 3O2 ---> 2AL2 O3

B) How many grams of NO (30.01 g/mol) are expected if 500g O2 (32 g/mol) reacts completely with excess ammonia (NH3) (17.03 g/mol)?

4NH3 + 5O2 -----> 4NO + 6H2O

PS: I give best answer to those who explain the logic in each step behind the answer.

2007-11-11 12:29:45 · 2 answers · asked by Someguy25 4

Okay, im doing chemistry homework. I cant work out how to get the pH if only the OH- is given. Can anyone give me a formula for doing it?

Daniel

2007-11-11 12:25:54 · 3 answers · asked by Peter 1

I know this is extremely stupid but picture this: A guy is fighting a "rust monster" that could turn his metal weapon into rust. Thing is, he doesn't want that to happen, so what metals don't rust that could be used to make a sword?(Not gold obviously)

2007-11-11 12:14:14 · 15 answers · asked by Anonymous

I can't remember (or seem to be able to find) the exact equation for percent ionization.. it's the same thing as percent dissociation, right? This is pertaining to acids and bases if it makes a difference..

2007-11-11 11:54:24 · 1 answers · asked by xxsoccerchickxx_84 1

You are given a container of 1 mole of helium gas (He), and an identical container of 1 mole of oxygen gas (O2). Both gases are at STP. Which statements are true or false:

a) both gas samples have the same number of particles (molecules)
b) both gas samples have the same number of atoms
c) Both samples have the same mass
d) Both samples have the same density
e) both samples have the same average kinetic energy
f) the particles of both samples have the same average speed
g) if there was an identical pinhole in both containers, both samples would efuse at the same time
h) The actual volume occupied by the gas particles is the same for both samples
i) both are ideal gases.

2007-11-11 11:47:36 · 2 answers · asked by jessulkerz 1

22.6 g degrees celcius to 154.5 degrees celcius?

2007-11-11 11:42:33 · 1 answers · asked by darkraven_222000 1

I am supposed to calculate the pH of a solution that is .49 M NH4ClO4. Can anybody help me?

2007-11-11 10:20:31 · 1 answers · asked by Anonymous

a) If 4.0g of hydrogen are made to react with excess carbon monoxide, how many grams of methanol can theoretically be produced according to the equation?

b) If 28.0g of methanol are actually produced, what is the percent yield?

2007-11-11 10:12:11 · 2 answers · asked by fretdancer 1

1. Mg2+, O2-
2. Mg2+, Se2-
3. Mg2+, S2-

2007-11-11 10:02:58 · 2 answers · asked by Jessica F 1

Consider the reaction:

H2O(g) + CO(g) = H2(g) + CO2(g)

Which of the following statements are true and which are false.

When Q > K the system will spontaneously shift to the left.


1 mol of H2O(g) and 1 mol of CO(g) are placed in a vessel and 1 mol of H2(g) and 1 mol of CO2(g) are placed in another of equal volume. At equilibrium, at 350°C, the amounts of CO(g) in the two vessels are equilvalent.


At equilibrium, individual molecules may be subject to rapid chemical transformations.


At equilibrium, the overall composition of the reaction mixture is not changing.


Amounts of all reactants and products corresponding to an exact equilibrium composition for this reaction are sealed in a vessel. The CO placed in the vessel is labelled with 14C. After an indefinite period of time 14C may be found in both CO and CO2 molecules.


The equilibrium constant is independent of the initial concentrations.

2007-11-11 09:42:36 · 2 answers · asked by vik s 1

At a certain temperature K = 1.10×103 for the reaction:

Fe3+(aq) + SCN-(aq)= FeSCN2+(aq)

1.90×10-1 mol of Fe(NO3)3 is added to 1.27 L of 1.57×10-2 M KSCN.

Neglecting any volume change and assuming that all species remain in solution--:

Calculate the equilibrium concentration of Fe3+ (in mol/L).



Calculate the equilibrium concentration of SCN- (in mol/L).


Calculate the equilibrium concentration of FeSCN2+ (in mol/L).

2007-11-11 09:42:17 · 2 answers · asked by vik s 1

what is the net ionic equation and total ionic equation

2007-11-11 09:37:26 · 1 answers · asked by vidhu m 1

At a particular temperature, Kp = 0.390 for the reaction

N2O4(g) = 2NO2(g)

A flask containing only NO2(g) at an initial pressure of 9.60 atm is allowed to reach equilibrium. Calculate the total pressure in this flask at equilibrium.



With no change in the amount of material in the flask, the volume of the container in question is increased to 2.000 times the original. Assuming constant temperature, calculate the (new) total pressure, at equilibrium.

2007-11-11 09:35:43 · 1 answers · asked by vik s 1

Consider the reaction:

H2O(g) + CO(g) = H2(g) + CO2(g)

Which of the following statements are true and which are false.

When Q > K the system will spontaneously shift to the left.


1 mol of H2O(g) and 1 mol of CO(g) are placed in a vessel and 1 mol of H2(g) and 1 mol of CO2(g) are placed in another of equal volume. At equilibrium, at 350°C, the amounts of CO(g) in the two vessels are equilvalent.


At equilibrium, individual molecules may be subject to rapid chemical transformations.


At equilibrium, the overall composition of the reaction mixture is not changing.


Amounts of all reactants and products corresponding to an exact equilibrium composition for this reaction are sealed in a vessel. The CO placed in the vessel is labelled with 14C. After an indefinite period of time 14C may be found in both CO and CO2 molecules.


The equilibrium constant is independent of the initial concentrations.

2007-11-11 09:21:24 · 1 answers · asked by vik s 1

1 0.4
2. 1.3
3 0.6
4 7.0
5 2005
6 4.5

2007-11-11 08:48:23 · 1 answers · asked by Anonymous

WHAT EQUATION IS USED AND HOW?
THESE ARE THE CHOICES I AM GIVEN 1 0.859
2. 1.16
3. 1.2
4 1.9
5 0.460
6 .523
7. 2.2

2007-11-11 08:42:02 · 1 answers · asked by Anonymous