Chemistry - October 2007

its the combined gas laws... (P1*V1)/T1 = P2*V2)/T2
can someone explain how to rearrange it so i can get V1 values

2007-10-31 08:06:24 · 5 answers · asked by Anonymous

Science

2007-10-31 08:05:29 · 1 answers · asked by Kalluto~ 2

2007-10-31 07:23:32 · 4 answers · asked by John T 1

Urgent ..Please help me :)

2007-10-31 07:23:24 · 3 answers · asked by Anonymous

CCl4, an important commercial solvent, is prepared by the reaction of Cl2(g) with a carbon compound. Determine H° for the following reaction.
CS2(l) + 3 Cl2(g) CCl4(l) + S2Cl2(l)

Use appropriate data from the following listing.


CS2(l) + 3 O2(g) CO2(g) + 2 SO2(g) H° = -1077 kJ
2 S(s) + Cl2(g) S2Cl2(l) H° = -58.2 kJ
C(s) + 2 Cl2(g) CCl4(l) H° = -135.4 kJ
S(s) + O2(g) SO2(g) H° = -296.8 kJ
SO2(g) + Cl2(g) So2Cl2(l) H° = +97.3 kJ
C(s) + O2(g) CO2(g) H° = -393.5 kJ
CCl4(l) + O2(g) COCl2(g) + Cl2O(g) H° = -5.2 kJ

2007-10-31 07:14:18 · 3 answers · asked by Anonymous

Determine H° for the following reaction.
N2H4(l) + 2 H2O2(l) N2(g) + 4 H2O(l)

You are given these data.


N2H4(l) + O2(g) N2(g) + 2 H2O(l) H° = -622.2 kJ
H2(g) + 1/2 O2(g) H2O(l) H° = -285.8 kJ
H2(g) + O2(g) H2O2(l) H° = -187.8 kJ

2007-10-31 07:13:51 · 1 answers · asked by Anonymous

help H3COCH3

i cant figure out the lewis structure for this one. i come up with a total of 26 dots

2007-10-31 07:13:41 · 2 answers · asked by nikkylyn 5

You are given the following data.
H2(g) + 1/2 O2(g) H2O(l) H = -285.8 kJ
N2O5(g) + H2O(l) 2 HNO3(l) H = -76.6 kJ
1/2 N2(g) + 3/2 O2(g) + 1/2 H2(g) HNO3(l) H = -174.1 kJ

Calculate the H for the reaction given below.
2 N2(g) + 5 O2(g) 2 N2O5(g)

2007-10-31 07:13:31 · 1 answers · asked by Anonymous

Calculate w and E when one mole of a liquid is vaporized at its boiling point (71°C) and 1.00 atm pressure. Hvap for the liquid is 37.1 kJ mol-1 at 71°C.

2007-10-31 07:11:40 · 1 answers · asked by toocool 1

Combustion of table sugar produces CO2(g) and H2O(l). When 1.92 g of table sugar is combusted in a constant volume (bomb) calorimeter, 31.56 kJ of heat is liberated.
(a) Assuming that table sugar is pure sucrose, C12H22O11(s), write the balance equation for the combustion reaction.

Calculate E in kJ/mol C12H22O(s) for the combustion of sucrose.


Calculate H in kJ/mol C12H22O(s) for the combustion of sucrose at 25°C.

2007-10-31 07:11:00 · 2 answers · asked by toocool 1

A 134 g stainless steel ball bearing (sp ht = 0.50 J g-1 °C-1) at 525°C is dropped onto a large block of ice at 0°C, what mass of liquid water will form? (H°fusion = 6.01 kJ/mol H2O(s))

2007-10-31 07:10:09 · 1 answers · asked by toocool 1

A 3.34 g sample of aluminum pellets (specific heat capacity = 0.89 J °C-1 g-1) and a 10.00 g sample of iron pellets (specific heat capacity = 0.45 J °C-1 g-1) are heated to 100.0°C. The mixture of hot iron and aluminum is then dropped into 95.2 g of water at 21.7°C. Calculate the final temperature of the metal and water mixture, assuming no heat loss to the surroundings.

2007-10-31 07:09:35 · 1 answers · asked by toocool 1

2007-10-31 07:07:41 · 1 answers · asked by Anonymous

2007-10-31 07:01:18 · 1 answers · asked by Anonymous

Lets say I have a 20.0 gram sample of aluminum, how many atoms of aluminum do I have. Im having a hard time figuring this out. Please help.

2007-10-31 06:57:19 · 3 answers · asked by Anonymous

i know joules is the measure of work but i am not sure how to calculate it,my teacher just wont help me ,please tell me each step to calculate these plz dont give me just the answer, i wanna learn how to do it.


when 25.0 grams of water are cooled from 20.0 cellcius to 10.0 celsius the number of joules of heat energy released is
a 42 b 105 c 840 d1050

how many kilojoules of heat energy are absorbed when 100.g of water are heated from 20.0c to 30.0 c by the addition of 3762 j. what is the mass of water? a0.03g b 30.0g
c 0.30 g d 300.0

2007-10-31 06:32:37 · 5 answers · asked by Anonymous

2007-10-31 06:29:58 · 2 answers · asked by Anonymous

I'm studying Markovnikov's rule and I know that the addition of HX to an alkene, the X goes on the C that has the most alkyl group, but i just see that C1 only contains the ethyl group, where is the other alkyl group?? and how does C2 even have 1 alkyl group??

2007-10-31 06:04:01 · 2 answers · asked by Anonymous

Ions are electrically charged particles that are formed when certain compounds are dissolved in water. These solutions will conduct electricity. The Swedish scientist Svante Arrhenius coined the term ion (which means wanderer) to explain why solutions of electrolytes will conduct an electric current. When an electrolyte forms into a solution, it dissolves or dissociates into ions, a process called ionization. If a substance does not ionize, it will not conduct an electric current. Electrolytes include most acids, bases, and salts. Some conductors include hydrogen and sodium chloride, copper sulfate, and potassium nitrate. Substances that are not electrolytes include distilled water, sugar water, and most organic compounds. Which of the following is a nonelectrolyte?



A) H 2 SO 4 (sulfuric acid)
B) HCL (hydrochloric acid)
C) C 3 H 8 (propane gas)
D) NaCl (table salt)

2007-10-31 05:53:08 · 16 answers · asked by lil_nisha142000 1

2007-10-31 05:38:10 · 3 answers · asked by ptolemyixi 1

Calculate the energy difference (E) for the photon absorbed when a hydrogen atom undergoes a transition from n = 1 to n = 4 for 1 mol H atoms.

2007-10-31 05:23:28 · 1 answers · asked by jnester0289 1

a. 2-propanol
b. propane
c. 1-propene
d. butane

2007-10-31 05:09:04 · 7 answers · asked by lyndon y 1

a. they may have different boiling points?
b.they have different densities
c. they may have different reacitvity
d. all true

2007-10-31 05:00:42 · 4 answers · asked by lyndon y 1

A student weighs an empty flask, aluminum foil, and copper wire and finds the mass to be 54.8680g. She then adds about 5.0mL of an unknown liquid and heats the flask in a boiling water bath to 99.0°C. After all the liquid is vaporized, she removes the flask from the bath and weighs it after it has cooled. The weight of the flask, foil, wire, and unknown liquid was found to be 55.8020g. The volume of the flask is 242.5mL and barometric pressure was 747.0mm Hg (Torr).

What was the pressure of the vapor in the flask in atm?
I have 0.9829 atm

What was the temperature of the vapor in K? the volume of the flask in liters?
I have 372.15K and 0.2425L

What was the mass of the vapor that was present in the flask?
I have 0.9340g

What is the mass of one mole of vapor?
I have 119.2g/mol

Also if all of the unknown liquid has not fully vaporized, would the result for the molar mass be higher, lower, or the same as a properly done experiment?
I said it would be the same.

2007-10-31 04:58:55 · 3 answers · asked by Anonymous

1. Cobalt-60 is radioactive isotope use to treat cancers of the brain and other tissues. A gamma ray emitted by an atom of this isotope has an energy of 1.33 MeV ( million-electron volts 1eV= 1.602 X 10^-19. What is the frequency in (Hz) and wavelength in (m) of this gamma ray?

2.A microwave emits photons with a wavelenght of 1.55 X 10^-2m. What is the energy of each photon in J?

3.What is the energy of a photon of blue light of wavelength 475nm in J?

2007-10-31 04:21:30 · 1 answers · asked by Christina S 1

2007-10-31 04:14:13 · 3 answers · asked by Anonymous

2007-10-31 04:12:47 · 4 answers · asked by Anonymous

a) volume of particles are assumed to be large compared to distances between them

b) particles are in constant random motion

c) forces of attraction between particles effect the observed pressure

d) collisions between particles, and between particles and the container wall are both inelastic collisions

e) observed pressure is caused by collisions of particles with the conatiner walls

f) velocity of particles is independent of temperature

2007-10-31 03:19:12 · 3 answers · asked by unique_fantasy 1

a scuba diver's tank contains 0.29 kg of O2 compressed into a volume of 2.3L

I know the answers..but i dont' know how to get it!!

(a) calculate the gas pressure inside the tank at 9 degrees C.
answer: 91 atm

(b) what volume would this oxygen occupy at 26 degrees C and .95 atm?
answer: 2.3 x 10^2 L

2007-10-31 02:54:25 · 3 answers · asked by WynnLasVegas 1

Hello my major is mechanical engineering so my knowledge in chemistry is somehow limited, but i was wondering everyday people Why are we here on earth???? to what cause??. So i was thinking and i had my theorie that there is no cause for us but we are rather a consequence of the fact that atoms need to bend altogether and that is how molecules were created (because if all atoms were nobles there wouldn't be any molecules, universe...) and they in turn created acide amino than created humans blablabla. So what do you think is my theorie credible enough or should i shut up and stick to mecanichal engines...

2007-10-31 02:21:39 · 2 answers · asked by Ifleyfel 2